High Energy Physics - Phenomenology

The LUX-ZEPLIN experiment has reported one nuclear-recoil candidate at $248\kev$ in an extended-energy search. We construct an anomaly-free $U(1)_{B-3L_\tau}$ model in which an $840\gev$ complex scalar undergoes an endothermic transition with splitting $320\kev$. A $160\mev$ vector with dark charge $Q_\chi=1$ gives $0.958$ accepted events in a public LZ-response reconstruction while scalar annihilation yields $\Omega h^2=0.1200$. The physical nucleon ratio $f_n/f_p=-0.86985$ suppresses solar iron capture, leaving $C_\odot=1.09\times10^{19}\,{\rm s}^{-1}$. We then evolve captured particles in energy, angular momentum, and internal state, including finite collision rates, thermal nuclear velocities, and the excited-state decay. The distribution stalls at an equivalent radius $r_{\rm eff}=0.194$--$0.198\rsun$, for which $\Gamma_{\rm ann}=(1.33$--$1.38)\times10^{15}\,{\rm s}^{-1}$, below a model-specific IceCube public-data proxy by more than three orders of magnitude. The benchmark also lies below the dedicated NA64 $B-L$ limit. Thus solar-neutrino bounds on electroweak inelastic dark matter do not transfer model-independently to light-mediator scalar realizations.

The recent 248-keV nuclear recoil candidate reported by LUX-ZEPLIN has renewed interest in endothermic inelastic dark matter, motivating us to examine its capture in primordial dark stars. Relative to the conventional elastic-capture picture in dark star evolution, endothermic capture adds two qualitative features. First, it opens only after the growing star crosses a compactness threshold, expressed as a kinematic radius $R_{\rm kin}\propto\mu_{\chi}M_\star/\delta$ set by the stellar mass, the dark-matter--nucleus reduced mass and the mass splitting. The accreting growth carries the star through the threshold, and the capture rate turns on quadratically above it. Second, although newly captured particles generically begin on nonthermal bound orbits, endothermic kinematics can keep this normally transient population spatially extended, turning it into a persistent reservoir rather than an intermediate step toward a thermal core. Following complete chains of state-changing collisions, we find that the reservoir compacts sharply and then stalls, because a ground state particle below a compactness-dependent orbital energy has no allowed up-scatter anywhere in the star. A percent-level radius contraction reopens the relaxation. These kinematic results do not depend on whether the excited state decays promptly or is long-lived. As a result, inelastic capture does not replenish a thermal annihilation core. The captured population forms an evolving orbital distribution that sets up the co-evolutionary dynamics between the star and the dark matter in the core and the reservoir, which we develop in a companion paper.

Recent developments in the Swampland program motivate the existence of a mesoscopic Dark Dimension of size $0.1-10~\mu$m with bulk Majorana fermions in the $1-10$ keV range. Motivated by this, we derive terrestrial constraints on Majorana bulk neutrinos as a function of the compactification radius. After determining the mass spectrum and mixing structure, we confront the model with Daya Bay neutrino-oscillation data, the KATRIN beta-decay bound, and the KamLAND-Zen neutrinoless double beta decay limit. For the latter, we obtain a closed-form expression for the effective Majorana mass and show that the Kaluza-Klein tower efficiently screens neutrinoless double beta decay when the nuclear momentum exceeds the compactification and Majorana scales. In the Dark-Dimension window, beta decay provides the strongest constraint, pushing the allowed Yukawa couplings down to $\mathcal{O}(10^{-3})$. Oscillation and neutrinoless double beta decay searches remain complementary, probing smaller and larger Majorana masses, respectively. For completeness, outside the Dark-Dimension assumptions, we investigate how hierarchical Majorana masses can weaken the constraints.

Ultralight dark matter could be an axial vector field, a simple possibility which motivates new experiments. Couplings to fermions, through an axial vector current or a dark electric dipole moment operator, lead to enhanced spin torques compared to axion dark matter. An axial vector also has an analogue of the axion-photon coupling, though its consistent realization requires a photon mass. Under this "axial-photon" coupling, the effect of a background magnetic field is suppressed, and the strongest experimental probes involve polarimetry, electric fields in superconducting cavities, and the cosmic microwave background. Since a massive axial vector is dual to a massive two-form, our results also apply to "Kalb-Ramond" dark matter motivated by string theory.

In a broad class of inflationary models, the leading non-Gaussian bispectrum arises from one-loop rather than tree-level processes. However, realistic one-loop contributions remain largely unexplored for phenomenologically relevant masses beyond the simplest bubble diagrams. This is insufficient for observational purposes because, for generic masses and couplings, triangle contributions need not be suppressed relative to their bubble counterparts. We present a numerical method for evaluating scalar one-loop in-in diagrams contributing to the inflationary bispectrum at fully general external momenta and masses. First, the Witten-Feynman parameterization reduces de Sitter loop integrals to generalized Euler-Mellin integrals governed by Symanzik graph polynomials. Unfortunately, the exponents of the polynomials in the integrand become complex for sufficiently heavy masses, leading to sign problems when evaluating the integral using standard numerical techniques. To remedy this problem, we introduce the reduced Schwinger method, which evaluates a highly oscillatory subintegral analytically to obtain a Gauss hypergeometric kernel, leaving the remaining integrals to standard numerical quadrature. We validate the algorithm by reproducing known analytic results for the tree-level bispectrum in terms of ${}_3F_2$ functions, and then apply it to the one-loop bubble and triangle contributions at general kinematics. This yields the first direct numerical evaluation of the complete one-loop bispectrum, valid across the full kinematic range. Using these numerical results, we construct bispectrum templates and compare them with CMB data.

An eV-scale QCD axion comprising the observed dark matter (DM) abundance is expected to generate a photon line at infrared energies that would be observable or near-observable in data collected by the James Webb Space Telescope (JWST), as might more general axion-like particles (ALPs) over a broader range of masses and couplings. This has motivated a number of efforts to either forecast JWST sensitivities to a QCD axion or realize them through analyses of publicly available datasets. At present, no consensus exists; leading analyses disagree by as much as an order of magnitude in terms of axion-coupling sensitivity, implying an orders-of-magnitude discrepancy in raw flux density sensitivity, and consistency between the analyses and prior forecasts is unclear. We address these outstanding discrepancies with a bespoke data reduction and flexible nonparametric inference procedure that lead to well-controlled and robust limits on the decay of eV-scale axion DM, consistent with previously forecasted sensitivities. We further demonstrate that the strongest previously claimed sensitivities exceed those attainable by any analysis of the datasets from which they were derived. We exclude QCD axion DM for masses between $500\,\mathrm{meV}$ and $2.5\,\mathrm{eV}$ using NIRSpec data, while setting limits on ALP DM complementary to other astrophysical constraints at masses between $100\,\mathrm{meV}$ and $500\,\mathrm{meV}$. However, we find the sensitivities to be systematically limited, and therefore unlikely to be improved upon by ongoing data collection or re-analysis unless instrumental modeling and data reduction pipelines improve considerably.

We develop an Efficient Wake procedure for computing the distribution of hadrons originating from jet wakes in heavy ion collisions - the hydrodynamic response of a droplet of quark-gluon plasma to the energy and momentum deposited in it by high-energy partons propagating through it. The procedure employs the linearity of linearized hydrodynamics and takes account of the effects of both longitudinal expansion and transverse radial flow on the hydrodynamic evolution of the wakes and on the resulting particle production at the freezeout hypersurface. It makes repeated use of template solutions to linearized hydrodynamics in a Bjorken flow background with no transverse flow, templates that need only be computed once, and uses suitable rotations and boosts to map fluctuations from these templates to fluctuations at a point on the freezeout hypersurface in a way that incorporates the effects of the radial flow. We benchmark this procedure by comparing its results to results obtained from full $(3+1)$-dimensional nonlinear hydrodynamics calculations, find reasonable agreement, and find that our Efficient Wake procedure yields a much better description of the distribution of hadrons originating from jet wakes than does the older oversimplified procedure employed in the Hybrid Model. And, the Efficient Wake procedure is computationally efficient: it is at least tens of thousands of times faster than full nonlinear hydrodynamics calculations. Hence, we anticipate that when our new procedure is implemented in Monte Carlo analyses of jets in heavy ion collisions, for example in the Hybrid Model, it will greatly improve the description of the soft component of many jet and jet substructure observables as compared to experimental data.

We study the phenomenology of the topological portal between QCD and pseudo-Nambu--Goldstone dark matter proposed in~\cite{Davighi:2024zip}. We construct a weakly coupled ultraviolet completion in which a vector mediator gauges a baryonic current of QCD for the light quark flavours, linking it to dark pions parametrizing the coset $SU(2)_D/U(1)_D$. As a concrete anomaly-free realisation, we gauge the leptophobic combination $B_1+B_2-2B_3$. This completion allows us to calculate thermal coannihilation beyond the regime of validity of the pion effective theory, including resonant mediator effects, and to test the resulting thermal target with boosted-dijet and monojet searches at the LHC, with LEP and bottomonium data, and with flavour observables. These collider signatures follow directly from the symmetry structure required by matching onto the topological portal. At low momentum transfer, the topological operator instead controls the decay of the heavier dark pion, which is long-lived. A future high-statistics $Z$ factory, such as FCC-ee, can probe the low-mass region where hadron-collider sensitivity deteriorates, providing complementary tests of the topological portal.

The Sommerfeld enhancement (SE) from long-range interactions, and the related bound state formation rate, can be important non-perturbative inputs to dark matter (DM) annihilation signals. In the presence of singular interaction potentials, the conventional boundary conditions of the Schrödinger equation fail, obfuscating the computation of SE, its physical origin, and its relation to bound states in such potentials. In this work, we clarify the origin of SE in singular potentials in a two-fold manner: using the framework of velocity power counting in non-relativistic effective field theory (NREFT), and via position-space regularization of singular potentials at short distances to compute SE and bound states. We illustrate our findings through the case of pseudoscalar mediators interacting with massive Dirac DM. We find that when such a system arises from a UV-complete theory at weak coupling, no SE is generated. However, in the case of a derivatively coupled pseudoscalar, where the interaction is described by a higher-dimension operator in an effective theory, SE (and bound states) can occur for weak couplings if there is a large hierarchy between the cutoff scale of the effective theory and the dark matter mass. This SE is sensitive to the choice of the UV completion of the potential at short distances, but a non-negligible SE can persist even when the UV physics alone would not generate any SE; we elucidate the interplay of UV and IR physics in this case.

We consider a class of dijet event shapes which tend to angularity in the forward limit. The factorisation formula for this class of event shapes differs from angularity only in the soft function. The NNLO soft function of an event shape in this class is therefore the only missing ingredient required for NNLL' resummation. We describe a modular approach to the calculation of the soft function for any event shape in this class, at NLO and NNLO. Much of the structure of the soft function can be written in terms of a single rapidity integral. The remainder can be computed as a three-dimensional numerical integral for which we provide a code. To demonstrate the flexibility of our approach, we compute the NNLO soft function for three new families of event shapes in this class. Potential applications include the investigation of hadronisation effects at future $e^+ e^-$ colliders, or through the re-analysis of archived data.

We present a phenomenological framework for fully-heavy tetraquark spectroscopy based on the spectral theory of weighted graphs. The four valence partons are vertices of the complete graph $K_4$, with edge weights determined by colour-Casimir factors in the two colour-singlet diquark-antidiquark channels, $\bar{3}\otimes3$ and $6\otimes\bar{6}$. A physical state is described as a coherent mixture of these channels through one mixing angle. Unlike an earlier Laplacian-based version, we obtain the spectrum by directly diagonalising the colour-weighted adjacency matrix. We show analytically that the two constructions are inequivalent and that the Laplacian reverses the physically expected relation between colour attraction and mass ordering. Using $X(6900)$, $X(7100)$, and the tentative $X(7200)$ to determine the mixing angle, energy scale, and effective charm mass, we find $\alpha=0.740$, $\gamma=23.2$ MeV, and $m_c=1.77$ GeV. Since three parameters are fixed by three inputs, this calibration is not an independent statistical test. The predictive content comes from applying the same parameters elsewhere: the all-bottom ground state is predicted at 18.7-18.9 GeV, while the colour-only model under-binds $T_{cc}^+$ by about 93 MeV. This discrepancy provides a quantitative indication of long-range molecular dynamics beyond a compact four-parton colour graph. We discuss the tentative nature of $X(7200)$, the tension with the CMS radial-excitation interpretation, and the limitations of a static model without spin, orbital, or decay dynamics.

The high-energy nuclear recoil event with $E_R\simeq248$ keV recently reported by the LZ collaboration, with a background-only significance of $2.6\sigma$, offers an intriguing window into dark matter scattering beyond the conventional elastic picture. We study an inelastic scalar dark matter scenario within a generalized chiral $U(1)_{B-L}$ framework. After symmetry breaking, the dark sector scalar gives rise to two nearly degenerate states with a small mass splitting. The lighter state serves as the dark matter candidate and couples off-diagonally to the $Z'$ boson, leading to endothermic inelastic scattering. The resulting kinematics suppress the contribution from low-velocity dark matter while making the high-velocity tail increasingly relevant for nuclear recoils at higher energies. We identify the parameter space consistent with the observed relic abundance and current experimental constraints, and discuss the inelastic scattering kinematics relevant to the recent LZ observation, together with the complementary collider prospects for the associated $Z'$ boson.

We examine pure Yang-Mills theory glueball-glueball interactions in constituent-gluon approaches. Because of the large mass gap, Van der Waals interactions are relatively more significant than in light-quark QCD hadrons where the pion gives rise to strong Yukawa exchanges. We find that the colour Van der Waals potential, computed along the traditional lines of the quantum London-Eisenschitz-Wang force, is a relevant interaction at distances between about 0.66 fm (when the glueballs are in contact) to 1.9 fm (when the virtual string tension among the colour-polarized glueballs in the intermediate state breaks down). In employing a Cornell potential as the microscopic one among colour charges, we find that the Van der Waals interaction derived from the linear potential part closely cancels that of the Coulomb one for the ground state glueballs. This means that the interaction, while sizeable and capable of saturating the lattice data depending on parameters, is far weaker than the London force derived from the Coulombic part alone. (This suggests that one should move effective theories for glueballs beyond dilaton-type approaches and perhaps deploy some variant of Van der Waals Effective Field Theory.)

We study the effect of $s$-channel unitarity on the dynamical gluon mass scale, $m_g$, extracted from high-energy elastic $pp$ scattering. The elementary input is a Reggeized Landshoff--Nachtmann two-gluon exchange, in which the soft Pomeron is represented by a color-singlet pair of dynamically massive gluons. At Born level, the logarithmic and power-law mass solutions give $m_g=299$--$422~\MeV$, in the usual phenomenological range. When the same input is embedded in the eikonal and $U$-matrix schemes, the preferred values move to $m_g=749$--$1101~\MeV$. The enhancement, by a factor close to $2.5$, is stable against the ATLAS--TOTEM data choice, the running of the gluon mass, and the unitarization prescription. We trace this shift to the nonlinear mapping between the elementary two-gluon kernel and the physical impact-parameter profile. The scale inferred from elastic scattering is therefore a unitarity-dressed infrared scale, fixed jointly by the nonperturbative gluon propagator and by multiple-exchange dynamics.

The axion is a promising candidate for solving the strong CP problem. To solve this problem, the global U(1) symmetry must be preserved to a high degree of accuracy. However, it is well known that global symmetries are explicitly violated by quantum gravity effects, giving rise to what is referred to as the axion quality problem. In this paper, we investigate axionic wormholes as a source of explicit U(1) violation in Metric-Affine Gravity. This framework allows for spacetime torsion and non-metricity, which accommodate additional curvature-like and topological terms, such as the Holst and Nieh--Yan terms, that are absent from the metric and Palatini formalisms. We show that non-minimal couplings to these terms modify the wormhole dynamics and enhance the Euclidean wormhole action, thereby alleviating the axion quality problem. We also find that the viable parameter space is enlarged when two of these couplings are simultaneously present. We further identify representative parameter regions where the alleviation of the axion quality problem is compatible with inflationary constraints.

Quantum-information observables have emerged in recent years as new tools in nuclear and particle physics, from entanglement in top-quark pairs to spin correlations in $\Lambda\bar{\Lambda}$ production. Extending these studies to unequal-spin hadronic final states poses a fundamental challenge: the $6\times6$ density matrix of a qubit-qutrit system contains 35 independent spin parameters, but the decays of $\Lambda V$ pairs, with $V=\phi$ or $K^{*0}$, provide access to only 23 due to the hidden vector polarization from the strong decay. In this Letter, we formulate a qubit-qutrit quantum tomography (QQQT) technique for these spin-$\tfrac{1}{2}\otimes1$ systems and establish exact criteria for entanglement certification from the \textit{incomplete} density matrix. Compared with the $\Lambda\bar{\Lambda}$ system, QQQT of $\Lambda\phi$ and $\Lambda K^{*0}$ provides a new probe of nonperturbative QCD hadronization, enabling a direct comparison of the spin evolution of entangled quark pairs produced from the vacuum as they hadronize into a baryon or a vector meson.

We study the twist decomposition of the total cross sections for exclusive heavy vector meson electroproduction and photoproduction in the $\gamma^\ast p$ processes, within the leading logarithmic $1/x$ BFKL formalism. The Mellin transforms of the impact factors of the vector meson are calculated. We show that the higher twist contributions are strongly suppressed in the low-$x$ kinematical regime. Possible enhancement of the higher twists effects for nuclei targets is discussed.

Double parton scattering provides a unique probe of proton structure and is commonly characterized by the effective cross section $\sigma_\mathrm{eff}$. We examine, under the factorized ansatz for the double-parton-scattering cross section and without assuming any specific parametric form for the transverse profile, what the effective cross section can reveal about the transverse separation, $r$, between partons in the proton. We derive a sharp lower bound on the transverse partonic separation, $\langle r^2\rangle \ge 4\sigma_\mathrm{eff}/(9\pi)$, and demonstrate through explicit counterexamples that previously posited upper bounds do not hold. Our results establish, within the effective-cross-section parametrization of double parton scattering framework, that $\sigma_\mathrm{eff}$ can provide a sharp lower bound on partonic separation but cannot provide a general upper bound.

We realize a nearly pure higgsino dark matter candidate with mass of about 1 TeV in the Minimal Supersymmetric Standard Model coupled to the Starobinsky supergravity. The recent LUX-ZEPLIN 248 keV nuclear-recoil event has renewed interest in higgsino dark matter. In this framework, the particle spectrum, including the Higgs boson mass, the higgsino mass and its splitting, is connected to cosmic inflation observables via gravitational mediation of supersymmetry breaking and subsequent renormalization group evolution. We show that the Higgs boson mass predicted by the model agrees with the measured value within the quoted uncertainties for a broad range of bino-induced mass splittings. Wino-induced splitting leads to a Higgs mass several GeV higher and is therefore excluded.

In the strongly interacting massive particle (SIMP) scenario, dark matter is a pseudo-Nambu--Goldstone boson whose abundance is set by a three-to-two Wess--Zumino--Witten process. We study this scenario in an axion portal and find that the kinetic contact the canonical mechanism assumes is excluded by bounds on sub-GeV axion-like particles (ALPs). The dark sector then freezes out at its own temperature, so the relic abundance no longer fixes the self-interaction cross section but predicts the portal coupling instead. Moreover, the portal operator is Hermitian and even in the ALP field, so no trilinear ALP--pion coupling arises. The contact term then drives $\pi\pi\to aa$ with nothing to cancel against it, and we find the conversion four orders of magnitude faster than a trilinear estimate gives. This disfavours the minimal realisation in which the dark condensate alone generates the ALP mass. The realisation that survives instead makes the ALP slightly heavier than the dark pion. Matching the observed abundance then fixes the flavon vacuum expectation value at $V_\phi\simeq 1.1\times10^{10} \ {\rm GeV}$ and leaves the dark scale open over more than an order of magnitude. The decay $K^+\to\pi^+a$ requires the flavon to charge the leptons alone. The model then predicts a dark matter self-interaction of $0.20\,{\rm cm^2/g}$ at a dark pion mass of $140\ {\rm MeV}$, in a window running from $82$ to $169 \ {\rm MeV}$. The predictive power of the SIMP framework is therefore not lost but relocated, from the self-interaction to the flavon scale.

We investigate whether dimensional deconstruction can qualitatively modify long-range forces. We show that the deconstruction of a five-dimensional AdS spacetime effectively generates an inverse-square potential, which naturally gives rise to broad p-wave Sommerfeld resonances without fine-tuning. We then apply this mechanism to dark matter phenomenology.

We study an extension of the Standard Model with two complex scalar singlets, $S_2$ and $S_3$, charged under $\mathbb{Z}_2$ and $\mathbb{Z}_3$, respectively, and a muon-philic vector-like lepton $\psi$ carrying the same $\mathbb{Z}_3$ charge as $S_3$. The pseudoscalar associated with the $\mathbb{Z}_2$ sector remains stable due to the CP symmetry of the potential and serves as the dark matter (DM) candidate, with its mass generated through the corresponding soft breaking of the global $U(1)$ symmetry. The vector-like muon couples to the $\mathbb{Z}_3$ scalar and renders the second pseudoscalar unstable, thereby realizing an effectively single-component pNGB DM scenario. The pNGB nature strongly suppresses the tree-level spin-independent direct-detection cross section, while viable parameter regions reproduce the observed relic abundance and satisfy LHC monojet constraints. We further compute the one-loop contribution to DM-nucleon scattering and find that the resulting cross section remains below current experimental limits while being potentially accessible to future direct-detection experiments. At a multi-TeV muon collider, scalar mediated $t$-channel processes can significantly enhance vector-like-muon pair production. We perform a detailed multivariate analysis for a future muon collider at 3 TeV center-of-mass energy. We also identify viable benchmark points exhibiting strong first-order electroweak phase transitions (SFOEWPT) with successful bubble nucleation, which can generate potentially observable stochastic gravitational wave (GW) signals. These results highlight the complementarity of dark matter searches, muon-collider probes, and SFOEWPT, with the resulting GW signals providing an additional probe of the extended scalar sector.

Net-proton multiplicity distributions obtained by the STAR collaboration are analyzed in the grand canonical approach. A method of finding the baryon chemical potential $\mu_B$ immediately from such distributions is applied for the first time. The obtained values of $\mu_B$ are consistent both with those determined earlier using the statistical thermal model and with the results of the fit based on the Hadron Resonance Gas (HRG) model. We propose a criterion of thermalization of fireballs produced in heavy-nuclei collisions.

The LZ experiment has recently reported an observation of a single event with characteristics of a nuclear recoil at a high recoil energy of 248 keV, where no background events are expected. We show that such nuclear recoil event could be caused by high velocity dark matter particles originating from interactions with energetic cosmic rays. We analyze the expected recoil spectrum due to cosmic ray boosted dark matter within the non-relativistic effective theory formalism, and show that momentum-dependent operators, such as $\mathcal{O}_6$ and $\mathcal{O}_{10}$, can produce a spectrum that peaks at the observed energy.

We discuss a new family of publicly available collinear fragmentation functions (FFs) for pseudoscalar quarkonia, the NRFF1.0 set. It builds upon the Heavy-Flavor Non-Relativistic evolution (HF-NRevo) scheme, designed to describe heavy-hadron formation through leading-power fragmentation at moderate and large transverse momentum. Heavy-quarkonium production naturally involves both perturbative and non-perturbative QCD dynamics, from the production of the heavy $Q\bar{Q}$ pair to its formation into a physical bound state. Within NRFF1.0, Non-Relativistic Quantum Chromodynamics (NRQCD) provides the theoretical framework for calculating the FF inputs at the initial scale, which are subsequently evolved through the HF-NRevo scheme. This setup provides a precision baseline for investigating the underlying partonic hierarchy and jet structure across the moderate- to high-transverse-momentum regime. The explicit treatment of partonic channels and heavy-flavor thresholds makes this framework particularly suitable for exploring quarkonium-in-jet fragmentation, jet-quenching sensitivity, energy-loss mechanisms, and the emergence of medium-modified fragmentation patterns in the quark-gluon plasma.

Top-quark spin correlations provide a direct probe of the quantum numbers of a resonance decaying to $t\bar t$. We compare a CP-odd type-II two-Higgs-doublet-model pseudoscalar $A$ with a spin-1 leptophobic topcolor $Z'$ in the dilepton channel. The two hypotheses differ in the parton-level helicity correlation by $\Delta c_{\rm hel}\simeq0.43$, nearly independently of mass, and neutrino-weighted reconstruction preserves this separation with an effective dilution factor of about 0.66. At 400 and 800 GeV, the pseudoscalar normalization is anchored to CMS HIG-22-013 coupling limits, while the $Z'$ rate is matched to the pseudoscalar so that the comparison primarily tests spin structure. The leading-order $t\bar t$-only projection gives expected separations of 2.27 and 2.74 standard deviations at $3000\,{\rm fb}^{-1}$. Equalizing the selected signal yields gives pure spin-shape separations of 1.86 and 2.70 standard deviations. Profiling a Gaussian-constrained Standard Model $c_{\rm hel}$-shape nuisance gives 2.07 and 2.63 standard deviations for an optimistic sideband benchmark, or 1.67 and 2.26 for a weaker constraint. A local fixed-template extrapolation corresponds to five-standard-deviation discrimination at couplings about 22\% and 16\% above the reference values. A 1500 GeV $g=1$ point is shown separately. The reach is limited by the sub-percent signal fraction and control of the mass-dependent Standard Model spin shape, rather than by the intrinsic resonance-spin separation.

We present a Sherpa implementation of NLO corrections in dimension-six Standard Model Effective Field Theory (SMEFT) to the benchmark process $h\to b\bar b$. The calculation includes NLO QCD corrections matched to a parton shower using an MCatNLO-type framework for decays. Virtual weak effects are included as two-body matrix-element corrections in different electroweak input schemes, with the corresponding decay events also evolved with the QCD parton shower. We present numerical results for the inclusive decay rate and for differential distributions in the Higgs-boson rest frame, and illustrate how the decay implementation can be combined with an independently generated production sample by embedding it in associated $Zh$ production at the LHC. This proof-of-principle implementation demonstrates how NLO SMEFT corrections can be incorporated into the widely used Sherpa event generator, providing a basis for extensions to other processes and for SMEFT studies with realistic final states and fiducial cuts within that framework.

Semi-Visible Jets (SVJs) constitute a distinctive collider signature of strongly interacting dark sectors, embedding Dark Matter candidates, wherein jets contain both visible Standard Model objects and invisible dark hadrons, giving rise to correlated jet activity and missing transverse momentum. In this work, we investigate SVJs produced through a heavy Z' mediator and perform an study over a representative set of benchmark scenarios spanning different mediator masses and dark sector parameters in the context of so-called Hidden Valley Models. To characterise the signal, we combine global event kinematics with jet substructure observables, including the primary Lund Jet Plane (LJP), the two-point energy correlation, angularity, and charged hadron multiplicity. These representations are used to train five Deep Learning classifiers for SVJ vs standard jet discrimination: a Vision Transformer operating on LJP images, a JetLOV network based on a hierarchical clustering tree, a Multi-Layer Perceptron using high level observables, and two multimodal networks that combine the image-based or hierarchical representations of the radiation pattern with the high jet-level observables. This enables a direct combination of global kinematics, radiation patterns, and jet clustering structure. We find that global kinematic observables outperform the LJP and hierarchical jet representations, with the latter providing stronger discrimination than LJP images. Combining these complementary representations with global kinematics yields the best overall performance. More broadly, this study shows that unlocking the full discovery potential of SVJs would benefit from going beyond global kinematics to exploit the rich information encoded in their internal structure, providing a benchmark for future searches at the Large Hadron Collider.

We summarize the next-to-leading order (NLO) corrections to next-to-eikonal (NEik) quark background contributions to DIS structure functions. At NEik accuracy, in addition to corrections arising from the gluon background field of the target, DIS structure functions receive contributions from the $t$-channel quark exchanges, represented by insertions of the quark background field of the target. The latter provide the lowest order contributions in $\alpha_s$ at NEik accuracy. We show that the NLO corrections to the longitudinal NEik structure functions are finite, whereas those to the transverse NEik structure functions exhibit rapidity and ultraviolet (UV) divergences. We analyze these divergences and extract the finite contributions.

The bubble wall velocity is a key quantity in cosmological first-order phase transitions, with important implications for electroweak baryogenesis, gravitational wave signals, the dark matter relic density and primordial black holes formed during the phase transition, and so on. However, it is often treated as a free input in phenomenological studies, while a self-consistent determination remains challenging. In this work, taking the complex singlet extension of the Standard Model as an example, we investigate the bubble wall dynamics and velocity in a specific electroweak phase transition pattern where both the Higgs field and the coupled singlet scalar experience friction. The microscopic friction arising from particle interactions with the plasma is evaluated using Boltzmann transport equations, while the macroscopic plasma response is described through hydrodynamic analysis. By applying the steady state force balance condition, we numerically determine the bubble wall velocity for different model parameters. We show that the wall velocity is governed by the competition between the driving force from the effective potential and plasma friction, and that its variation can significantly affect the baryon asymmetry. Our study provides a quantitative investigation of bubble wall dynamics in this overlooked phase transition pattern and its implications for early Universe phenomenology.

Naive estimates based on Einstein gravity with Lagrangian $\frac{1}{2}M_{pl}^{2}(R-2\Lambda)$ suggest that, if the radiation era extended back to the Big Bang (i.e., as far back as the classical spacetime background makes sense), this would result in an over-production of dark matter and a relic cosmic background of thermal gravitons. Here we revisit these conclusions in quadratic gravity, the minimal renormalizable completion of Einstein gravity, whose Lagrangian also includes the terms $\frac{1}{6}f_0^{-2}R^2-\frac{1}{2}f_{2}^{-2}C^{2}$. Assuming the radiation era does extend back to the bang, we find a novel relation between the coefficient $f_{2}$ and the dark matter mass $m_{dm}$, needed to obtain the correct dark matter abundance. This yields a new gravitational production mechanism for dark matter (e.g., stable right-handed neutrinos). Moreover, the presence or absence of the relic graviton background (detectable by forthcoming CMB experiments via its small imprint on $N_{\rm eff}$) will place new constraints on $f_{0}, f_{2}$.

We develop a systematic correspondence between massless contact amplitudes in an unbroken theory and massive contact amplitudes after spontaneous symmetry breaking. Our construction employs the spin-transversality (ST) massive amplitude basis, with the systematic high energy expansion through minimal-helicity-chirality (MHC) amplitudes. The resulting $U(2)=SU(2)\times U(1)_t$ description of a massive particle makes the semi-standard Young-tableau construction of massless Lorentz structures directly applicable to massive amplitudes. When the leading-order MHC component has a massless contact limit, it is one-to-one matched directly to its UV amplitude. Otherwise, five exceptional classes of ST amplitudes are identified, their first non-zero descendant components are matched through conserved current couplings to the massless contact amplitude. We apply the framework to the one-flavor electroweak sector of the Standard Model Effective Field Theory (SMEFT) through dimension eight, obtaining explicit relations between unbroken-phase Wilson coefficients and broken-phase ST amplitude coefficients for amplitudes with three to eight external particles.

The LUX-ZEPLIN (LZ) Collaboration recently reported the detection of a single nuclear recoil candidate event with a very high recoil energy. The lack of any corresponding low-energy events motivates models in which dark matter scattering with nuclei has a nontrivial momentum dependence or proceeds inelastically, suppressing the rate of low-energy recoils. In this study, we consider the constraints on inelastic dark matter, including scenarios favored by the LZ event, from the absence of an excess of high-energy neutrinos from the Sun in IceCube observations. We confirm the results of Pospelov & Ramani and show, more generally, that the lack of an excess of high-energy neutrinos from the Sun strongly constrains the parameter space in this class of models.

We investigate the effects of a massive invisible fermion in $\Lambda_b^0 \to \Lambda_c^+ \ell^- \bar{X}_{\rm inv}$ decays using a model-independent weak effective theory. Through a comprehensive angular analysis, we show that a nonzero invisible-particle mass leaves characteristic imprints on angular observables that can distinguish massless and massive invisible states. We further demonstrate that these observables provide strong discrimination among vector/axial-vector, scalar/pseudoscalar, and tensor interactions, as well as between left- and right-handed quark and lepton current operators.

We show that the inference problem of constraining the parton distribution functions of the proton from deeply inelastic scattering data can be formulated as a linear tensor reconstruction inverse problem. This means that instead of fitting model parameters to the world data, a reconstructive approach to solve a system of coupled linear functional integral equations can be formulated. We leverage the mathematical structures of the integral equations defined by perturbative QCD and global analysis to pose the problem of global analysis as a coupled system of linear integral equations, and construct a proof-of-principle methodology to solve it. To formulate this approach concretely, we review all next-to-leading order accuracy results for inclusive virtual photon, neutral current, charged current, heavy flavor production, and neutrino deep-inelastic lepton--proton scattering. This mathematical methodology of inference opens a path towards a model-bias-free extraction of the proton PDFs from the world data of deeply inelastic scattering in the spirit of indirect measurement employed in mathematical inverse problems, including robust estimation of uncertainties with reduced bias from model parametrization, while closely adhering to the established paradigm of perturbative QCD and global analysis.

We explore a fermionic dark matter (DM) extension of the Standard Model Effective Field Theory (SMEFT) and establish a complete renormalisation-group framework for its phenomenological investigation. We derive the anomalous-dimension matrix of all relevant dimension-five and dimension-six operators involving Standard Model (SM) and DM fields, enabling the consistent evolution of the associated Wilson coefficients (WCs) across energy scales. By combining renormalisation-group running with matching at the relevant thresholds, we construct a robust bridge between high-scale new physics and experimental observables. We then perform a comprehensive phenomenological analysis, evaluating the contributions of these operators to observables spanning a wide range of energies and deriving constraints on the WCs from current data. We obtain stringent and complementary bounds on the DM effective field theory (DMEFT) WCs from electroweak precision observables, flavour processes, lepton-flavour-violating decays, top-quark flavour-changing neutral-current decays, and invisible meson decays. Interpreted in terms of the effective scale of new physics, the resulting limits demonstrate that current precision measurements probe energy scales ranging from the TeV regime to several tens or even hundreds of TeV, highlighting the remarkable sensitivity of indirect searches to dark-sector interactions.

We develop an effective kinetic description for the interaction of gluons and magnetic fields during the pre-equilibrium stage of relativistic heavy-ion collisions. For this purpose, we formulate the Boltzmann-Vlasov equation with the interaction term modeled by the effect of the magnetic field on the elements of an electrically charged and colored dipole originating from the quantum fluctuation of gluons into quark-antiquark pairs. We find the numerical solution of the collisionless Boltzmann-Vlasov equation with a time-dependent magnetic field profile to determine the time evolution of the directional pressures. The presence of the magnetic field tames the growth of the transverse to longitudinal pressure ratio compared with the case in the absence of the magnetic field; however, the system does not isotropize since collisions are not included. We study the cases of initial gluon distributions with longitudinal anisotropies, as well as the case of an initial isotropic gluon distribution. In both cases, we find that the magnetic field produces a non-monotonic early-time response for large values of the initial magnetic field strength.

We study linear gravitational perturbations and the corresponding quasinormal-mode spectra of electrically and magnetically charged black holes in the presence of higher-order corrections to the Einstein-Hilbert action. In particular, we consider a four-derivative interaction that couples the Riemann tensor to the electromagnetic field strength in the unique (Horndeski) combination that preserves second-order equations of motion. We provide a comprehensive analysis of the stability conditions. We numerically confirm the absence of exponentially growing modes throughout the physically admissible region of parameter space where the theory remains free of pathologies. We then investigate in detail the properties of the quasinormal-mode spectra and identify several distinctive features induced by the higher-order interaction.

The growth of primordial black holes through the absorption of the surrounding plasma has recently been shown to exhibit a critical behavior during radiation domination. We extend this analysis to the reheating era and derive analytical solutions for general reheating histories. We show that reheating modifies the critical condition for runaway absorption, making it dependent on both the reheating dynamics and the black-hole formation time. We identify two distinct regimes: runaway growth occurring during reheating, or being triggered after the onset of radiation domination by the mass accumulated during reheating. More generally, we derive a simple composition law describing how independent mass- growth mechanisms combine across successive cosmological eras. Applying it to radiation absorption and inflaton accretion, we obtain analytical results in excellent agreement with the full numerical evolution.

The Batalin-Vilkovisky (BV) framework is a powerful technique for quantizing a wide range of gauge systems. This formalism employs fields and antifields--introducing a symplectic structure through the antibracket--to implement BRST symmetry, which captures the essence of gauge invariance. Within this context, we study the symmetry structure of a pure Yang-Mills theory with universal extra dimensions. We construct a BRST-invariant extended action for the $(4+n)$-dimensional theory depending on fields and antifields, which constitutes a proper solution to the master equation. The higher-dimensional spacetime and gauge symmetries are then hidden within their four-dimensional counterparts via canonical transformations. Gauge invariances are fixed by combining gauge-fixing procedures for both the standard and Kaluza-Klein (KK) fields. This procedure is implemented covariantly in the adjoint representation of the gauge group. While the standard gauge fields are fixed using the Background Field Method (BFM), the KK gauge excitations are fixed covariantly, as they transform as matter fields. Finally, the manifest $SU(N)$ gauge symmetry of the quantized theory is emphasized.

Origin and composition of ultra-high energy cosmic rays are still uncertain, particularly the rare events exceeding the Greisen-Zatsepin-Kuzmin cutoff and whose apparent arrival directions point to the Local Void. This work is an in-depth investigation of the possibility that such cosmic rays contain low-mass magnetic monopoles predicted in several recent theoretical models. Using a custom extension to CRPropa, a state-of-the-art code for modeling cosmic ray propagation, monopoles are tracked in the galactic environment under realistic assumptions on mass, magnetic charge, and initial phase-space distributions. Our simulations demonstrate that relic MMs follow filamentary ``Galactic magnetic funnels'', producing anisotropic arrival directions at Earth. The expected arrival directions are concentrated in a small region of the sky, which has significant implications for the design and interpretation of future searches. A comparison of the simulated arrival directions with the Pierre Auger Observatory dataset shows that the null hypothesis - no monopole contribution - is statistically preferred for the majority of cases. Using a profile-likelihood analysis that incorporates both directional and energy information, we set 90% C.L. upper limits on the integral MM flux of $< 2.1\times10^{-23}$ $\mathrm{cm^{-2}s^{-1}sr^{-1}}$.

We present a lattice-QCD determination of properties of the lightest scalar, pseudoscalar, vector, and axial-vector heavy-strange mesons. This includes the decay constants of all mesons, and the binding energies and Weinberg compositeness parameters of the positive-parity states. The calculations are performed with domain-wall fermions for the light and strange quarks and anisotropic clover actions for the charm and bottom quarks. We use seven ensembles generated by RBC/UKQCD with pion masses ranging from 431 MeV to 139 MeV and lattice spacings ranging from 0.114 fm to 0.073 fm, which allows us to perform combined chiral and continuum extrapolations. For the negative-parity mesons, we obtain $f_{D_s}=251.4(2.1)(0.4)(2.5)\:{\rm MeV}$, $f_{D_s^*}=272.5(4.3)(1.0)(2.7)\:{\rm MeV}$, $f_{B_s}=228.4(5.8)(0.5)(2.3)\:{\rm MeV}$, $f_{B_s^*}=229.2(4.4)(0.8)(2.3)\:{\rm MeV}$, $f_{D_s^*}/f_{D_s}=1.086(14)(11)$, and $f_{B_s^*}/f_{B_s}=1.003(22)(10)$. In the positive-parity sector, the finite-volume energies and decay constants are extracted using the GEVP from correlation matrices with three different types of hadron interpolating operators, including operators with covariant derivatives and meson-meson-scattering operators at both source and sink. After extrapolation to the physical point, we obtain $f_{D^*_{s0}}=136.6 (8.0)(4.0)(1.4)$ MeV, $f_{D_{s1}}=200 (33)(24)(2)$ MeV, $f_{B^*_{s0}}=207 (12)(8)(2)$ MeV, and $f_{B_{s1}}= 196 (16)(11)(2)$ MeV. Our results for $f_{B^*_{s0}}$ and $f_{B_{s1}}$ are the first from lattice QCD. Lüscher's method is used to find the infinite-volume bound-state masses. At the physical point, we obtain $m_{D^*_{s0}}-m_D-m_K=-48 (14)(4)$ MeV, $m_{D_{s1}}-m_{D^*}-m_K=-61 (15)(2)$ MeV, $m_{B^*_{s0}}-m_B-m_K= -69 (13)(4)$ MeV, and $m_{B_{s1}}-m_{B^*}-m_K=-77 (10)(5)$ MeV. Our analysis shows consistency with the positive-parity states being predominantly molecular.

In this work, we present a formalism to model the relativistic behavior of axions. The relativistic behavior of axions is surprisingly difficult to model precisely, as it involves oscillations on timescales much shorter than the Hubble timescale. To overcome this challenge, one typically resorts to some form of effective treatment, focusing only on the time-averaged description of the exact oscillations. Salehian, Namjoo & Kaiser provide a systematic framework for such treatment, based on the effective field theory formalism. While the aforementioned study was formulated for axion perturbations in the Newtonian gauge with no anisotropic stress, we extend the formalism to the synchronous gauge that is more conventionally used for numerical implementation in a realistic cosmological setting. Unlike their work, however, we propose a fluid interpretation in which the axion field can be identified as a perfect fluid at all times, both in the exact and effective regimes. Moreover, we present the effective field theory for the Newtonian gauge with non-zero anisotropic stress, making the original formulation more general and useful for scenarios where the matter content of the universe is multi-component. These results lay the theoretical foundation for a companion paper where we discuss how the axion field should be incorporated alongside other species in common cosmological Boltzmann solvers.

The cosmological evolution of ultralight axions typically involves rapid oscillations on the timescale of the inverse mass, making it challenging to resolve the dynamics at both the background and perturbation levels. In this study, we numerically implement a novel approach to this problem based on an effective field theory (EFT) -- that is, for the first time, capable of reconstructing the relativistic oscillations intrinsic to the axion field. Compared to other available techniques, the reconstruction of the rapid oscillations is unique to the EFT approach, which describes the axion effective field through a wavefunction representation with relativistic corrections, rather than through effective fluid variables. From a computational standpoint, our approach archives a high level of accuracy -- up to a subpercent agreement with the exact solution -- while remaining relatively fast compared to alternative methods. As such, it opens up new possibilities for high-precision predictions for axion searches with future cosmological experiments.

We consider Yang-Mills theory with two infinite parallel plates, separated by a distance $L$, that are perfect magnetic conductors (PMC) or perfect electric conductors (PEC). Recently, it was shown that the Gribov copy problem persists in such a setting. We then study the Gribov-Zwanziger (GZ) action in the presence of those boundaries using functional integral methods. Lagrange multiplier fields allow one to lift the boundary conditions into the action, after which the boundary modifications to the gluon propagator can straightforwardly be determined. In the PEC case, we provide evidence that, even when translation invariance is (partially) broken, the usual horizon term in the GZ action still restricts the functional integral to the Gribov region. We compute the Casimir energy for GZ with PMC or PEC plates, both directly from the functional integral and from the energy-momentum tensor, obtaining consistent results. We compare our analytical results with recent lattice data, in both 4D and 3D. A priori, one might expect that the boundary-modified gluon propagator introduces new $L$-dependencies into the GZ gap equation. This would make the Gribov mass $\gamma$ dynamically dependent on $L$, implying an interesting interplay with the Casimir energy. However, we show that no such dynamical $L$-dependence occurs within the current approximation.

The recent observation of a 220 PeV neutrino event (KM3-230213A) by the KM3NeT observatory presents a formidable challenge to standard astrophysical source models. We investigate the hypothesis that this ultra-high-energy signature originates from the terminal evaporation burst of a Primordial Black Hole (PBH). Since PBH evolution spans cosmic history, static vacuum approximations fail to capture early-universe dynamics. Embedding the PBH in a cosmological background via the McVittie spacetime, we demonstrate that early-universe cosmological accretion and expansion-suppressed Hawking emission shift the required initial mass window for a terminal burst occurring today. We show that although the early universe environment dictates the black hole's overall lifespan, its final explosion today ($z \approx 0$) is governed by standard Schwarzschild thermodynamics. This mechanism naturally produces the intense 220 PeV local flux while suppressing early emissions, thereby satisfying diffuse isotropic background limits. Consequently, this dynamical framework alters the mapping between current ultra-high-energy neutrino observables and the primordial curvature perturbations that seeded them.

Quantum field theory on curved and non-inertial backgrounds contains background- and foliation-dependent quantities in the canonical Lagrangian, the hypersurface inner product and bilinear form, as well as in the equal-time anti-commutation relations. In this work, we determine a local fermion-field redefinition that brings these canonical structures into their standard-Minkowski forms, i. e., the forms they assume in Cartesian inertial coordinates on Minkowski spacetime, where the zeroth world coordinate is identified as the coordinate of time. Starting from the generally covariant Dirac action minimally coupled to a spin-1 gauge field, we derive the corresponding Lagrangian, fermionic inner product, and quantization rule in an Arnowitt-Deser-Misner decomposition, formulated in arbitrary world coordinates. We identify the generalized temporal gamma matrix as the common geometric factor governing the canonical temporal structure of all three quantities. Using a field redefinition, we transform this generalized temporal gamma matrix to its standard-Minkowski form, thereby mapping the fermionic inner product and the equal-time anti-commutation relation to their standard-Minkowski expressions, while transferring the explicit background and foliation dependence to the transformed Lagrangian and fermion-field operators. We show that such a field redefinition necessarily consists of a local rescaling and a fixing of the local Lorentz frame. This procedure restores the conventional canonical normalization from standard-Minkowski spacetime used for fermionic mode quantization and occupation-number operators. The transformed Lagrangian consequently assumes a generalized first-order Schrödinger form, leading to the familiar rest-energy term and spacetime-magnetic couplings, as well as to the leading non-relativistic limit, in which temporal derivatives are separated from spatial ones.

In bottom-up holographic QCD (HQCD), two primary approaches are commonly employed: the potential reconstruction method, where the background geometry is fixed a priori and the dilaton potential is derived, and the direct method, where the potential is specified explicitly. While the reconstruction method is highly effective for capturing the phenomenological properties of QCD under extreme conditions, a subtlety arises in that the reconstructed potential depends on the chosen holographic boundary conditions. To address this issue, we propose constructing a dilaton potential designed to reproduce the typical features of HQCD phase transitions obtained by the reconstruction method, rather than one derived solely from HQCD vacuum solution. Using a light-quark model as an example, we construct a potential that captures the principal features of the phase structure of this model. Its parameters are determined at zero chemical potential by minimizing the deviation between the temperature dependence on the horizon position in the direct and reconstructed models and by fitting to the same position of a critical endpoint (CEP). The resulting minimal-potential model satisfactorily recovers the physics of the light-quark model even at relatively small chemical potential. Specifically, it yields a first-order phase transition (FOPT) line close to those obtained from the reconstruction method. Additionally, the minimal-potential model reproduces a rising Cornell-like quark-antiquark potential up to the hadronic distance $\ell=1.5$ fm, which we use as a phenomenological finite-distance criterion for confinement. The location of the confinement/deconfinement crossover in this minimal-potential model is also close to its counterpart in the original light-quark model.

Primordial Black Holes (PBHs) with masses below $\mathcal{O}(10^9)$g occupy an interesting region of parameter space that is largely inaccessible to conventional observations. Despite evaporating before Big Bang Nucleosynthesis (BBN), these PBHs can naturally generate a period of early matter domination in the early Universe. A primordial gravitational-wave background (GWB) provides a window onto this otherwise inaccessible regime, since the modified expansion history leaves a characteristic spectral feature associated with the onset and end of PBH domination. The locations of these characteristic frequencies can be used to reconstruct the underlying PBH parameters, in particular the PBH mass. For a freely propagating GWB, the location of these frequencies additionally allow the initial PBH abundance to be determined. We derive simple numerical relations that map these characteristic frequencies directly onto the PBH mass and initial abundance. Future GW experiments span a vast frequency range, providing sensitivity to PBH masses from the BBN bound of $\mathcal{O}(10^9)\,\mathrm{g}$ down to the lower bound of $\mathcal{O}(10)\,\mathrm{g}$. We find that the nanohertz signal reported by NANOGrav, if primordial in origin, is already probing PBH masses in the range $4$--$90\,\mathrm{Mg}$. GW observations therefore offer access to a vast region of PBH parameter space that is otherwise beyond the reach of current experiments.

We investigate non-invertible selection rules originating from the discrete $H$-gauging of theories with an underlying discrete global symmetry group $G$. To systematically describe these theories, we formulate a general framework for $H$-gauged models that incorporates generalized field transformations. Our approach naturally accommodates non-Abelian groups, for which multidimensional irreducible representations play an essential role. In such models with non-Abelian groups, the transformations induced by $H$ non-trivially mix the internal components of $G$-multiplets, potentially projecting out specific degrees of freedom. Consequently, conventional selection rules based on standard tensor product decompositions or conjugacy classes become insufficient. By analyzing the full semidirect product $G \rtimes H$, we introduce projected characters to derive necessary and sufficient conditions for non-vanishing $n$-point bare couplings. Furthermore, we demonstrate that the remaining field components obey an associative fusion-like algebra governed by their Clebsch-Gordan coefficients. Phenomenologically, these selection rules restrict allowed interactions and impose specific relations among coupling constants. We illustrate our results through concrete examples, including $\Delta(54) \cong \Delta(27)\rtimes \mathbb{Z}_2$ and $S_4 \cong A_4 \rtimes \mathbb{Z}_2$.

What if dark energy is recurrent throughout cosmic history? In this picture, episodes of scalar-field dark energy become less surprising and more natural features of cosmic evolution. We construct a homogeneous multi-axion cosmology with a transient contribution during Big Bang nucleosynthesis, two early dark energy components before recombination, and a thawing field that supplies the present dark-energy density. As Hubble friction weakens, the fields begin to roll at successive epochs set by their potential-curvature scales. Their initial displacements affect the rolling delays and peak energy fractions. The transient fields have third-power cosine potentials, whose sextic minima allow faster-than-radiation dilution during rapid, small-amplitude oscillations. All four fields are evolved in a common Friedmann background, with their first roll and subsequent dynamics resolved numerically. With reference matter and radiation densities taken from Planck 2018, the benchmark has a nucleosynthesis-era peak fraction of approximately $0.99\%$ near $z=10^9$. The two early dark energy fields peak near $z=7.9\times10^3$ and $2.4\times10^3$, with individual fractions of $8.6\%$ and $7.8\%$; their combined fraction reaches $9.7\%$. The late-time field is normalized to supply a present fraction of approximately $0.685$, while the three transients leave a combined fraction of approximately $6.0\times10^{-7}$. An aligned two-axion example illustrates the enhanced field range available for an inflationary extension. We also outline how searches for transient contributions to the expansion rate at other epochs could constrain additional axion scales.

We formulate the theoretical aspects of direct waves (DWs) in the case of extreme-mass merger. A DW is a source-driven waveform characterized by a complex frequency $\omega_{\rm G}$, which reflects the orbital motion of the particle in the vicinity of the black hole, including a part of the orbit inside the ergoregion: its real part is governed by frame dragging and its imaginary part by the redshift of the source. Using the Green's function technique, we derive the source-driven frequency $\omega_{\rm G}$, describe its screening by the potential barrier, and discuss its relation to dynamically excited quasinormal modes (QNMs). We also discuss the late-time decay of DW and predict that it decays with the third-order horizon mode. We then introduce a pole-splitting method, which divides the whole waveform into a QNM-pole sector and a non-QNM sector. Unlike QNM filtering, which multiplies the waveform spectrum by a filter function and thereby deforms it through a frequency-dependent time shift (i.e., group delay), our pole-splitting method merely divides the transfer function into pole and non-pole parts, separating the full waveform. Simulating a quasi-circular plunge into a Kerr black hole with medium and rapid spins, we find that the frequency and decay rate of the non-pole sector in the dominant mode, $\ell = m = 2$, evolve consistently with $\omega_{\rm G}$-or with its screened counterpart $\omega_{\rm screen}$-establishing the DW as a probe of the ergoregion and of the redshift effect around a black hole.

In this work, we propose a dark matter (DM) interpretation of the intensive gamma ray burst GRB 221009A. This indirect detection approach devotes to the decay of DM particles into high energy (HE) photons. In this context, a singlet scalar DM generated at the redshift of GRB 221009A is up-scattered by the high energy cosmic rays (HECRs) during its propagation to Earth. This highly boosted DM then possesses a high flux and undergoes a dominant di-photon decay before reaching the detector. The Large High Altitude Air Shower Observatory (LHAASO) probes such energetic gamma rays whereby has recorded a $\sim$13 TeV event for the aforementioned GRB.

We propose a novel scale-invariant model with the 3-3-1-1 gauge symmetry featuring a universal see-saw mechanism for all fermion masses, which, through the inclusion of additional vector-like quarks, provides a partial explanation for the observed fermion mass hierarchies. A discrete remnant of the gauge group, the matter parity ($P_M$), stabilises a fermionic dark matter candidate, and the scalar sector includes two triplets (minimal for 3-3-1 breaking) and two scalar singlets. We identify the lightest $P_M$-odd fermion, $f_d$, as a viable dark matter candidate. Our analysis shows that $f_d$ satisfies the observed relic density constraint within the mass range 220 GeV $< m_{f_d}$ 555 GeV , primarily due to resonant annihilation via the new scalar $H_2$. While this mass range depends on the symmetry-breaking scale $v_\chi$, which has a lower bound of $v_\chi \gtrsim 3.6$ TeV from LEP constraints on the $\rho_0$ parameter, we adopt a more conservative lower bound of $v_\chi > 10$ TeV. This choice is made to ensure that the $Z'$ boson mass remains above approximately $4$ TeV, and is motivated by recent LHC results and future projections for Z' boson searches, which provide more stringent constraints than previous bounds or those from the $\rho_0$ parameter. Spin-independent (SI) interactions dominate the direct detection phenomenology of $f_d$. We calculate the SI elastic scattering cross-section and find that parameter points satisfying the relic density constraint are consistent with current experimental limits from LZ and PandaX-4T for certain parameter choices, particularly depending on the $\alpha_{12}$ angle. Some regions of the viable parameter space lie below the neutrino floor. Prospects for detection by future experiments like XLZD and PandaX-xT are also presented and discussed.

We investigate particle production by a pseudo-Nambu-Goldstone boson (pNGB) in the spontaneous baryogenesis scenario for large misalignment angles. Since the fermionic backreaction is intrinsically nonlocal in time, the large-angle problem is in general difficult to treat directly. We argue that the adiabaticity conditions are parametrically satisfied in the model, allowing the backreaction to be described by a local Markovian approximation while retaining the nonlinear dependence of the pNGB potential on the angular field. Through a numerical study of arbitrary initial phases, we reproduce the cubic dependence of the baryon asymmetry for small oscillations and demonstrate that this behavior breaks down for large oscillations, especially for initial phases close to $\pi$. Our calculations indicate that particle production saturates as the initial phase approaches $\pi$ in Minkowski spacetime. The analysis is then extended to conformal Friedmann--Lemaître--Robertson--Walker (FLRW) spacetime, where the generated asymmetry shows a pronounced dependence on the damping rate of the pNGB motion. We further discuss the baryon-isocurvature bound on the ratio $H_\star/f$ and present sample parameter sets that satisfy this constraint at large misalignment. We also discuss the probability distribution of the baryon asymmetry.

Cosmological reheating bridges the inflationary epoch and the hot big bang phase, yet its underlying dynamics remain poorly understood. In this work, we investigate a minimal scenario in which the inflaton evolves under a simple power-law potential during reheating and interacts with other particles via renormalizable couplings. We show that inflaton quanta can be regenerated from the thermal bath even after the decay of the coherent inflaton field, unveiling a previously overlooked channel for inflaton particle production, which offers a novel window into probing reheating via consistency with observations and laboratory experiments. Remarkably, this mechanism may also account for the observed dark matter abundance, providing a natural link between early Universe dynamics and present-day cosmological observations.

We compute the twist-2 matching of transverse momentum dependent (TMD) helicity parton distribution and fragmentation functions at next-to-next-to-next-to-leading order (N$^3$LO) in QCD. This calculation entails the complete set of next-to-next-to-leading order (NNLO) Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) splitting functions govering the evolution of helicity-dependent parton distribution functions (PDFs) and fragmentation functions (FFs). Within TMD factorization framework, we quantify the impact of radiative corrections by completing the next-to-next-to-next-to-leading logarithmic (N$^3$LL) prediction for lepton-hadron transverse momentum imbalance in semi-inclusive deep inelastic scattering (SIDIS). Our results provide the most precise theoretical input for probing the helicity structure and confined motion of quarks and gluons at future electron-ion collider (EIC).

Relativistic 3D weak-neutral axial-vector four-current and spin distributions inside a nucleon (or a general spin-$\frac{1}{2}$ hadron) including three weak-neutral axial-vector form factors are investigated for the first time. We clarify that the relativistic 3D axial charge distribution in the Breit frame is completely described by the induced pseudotensor form factor $G_T^Z(Q^2)$ rather than by the axial form factor $G_A^Z(Q^2)$. We demonstrate that the quantity $R_A \equiv \sqrt{ \frac{-6}{G_A^Z(0) }\frac{\text{d} G_A^Z(Q^2) }{\text{d} Q^2} \Big|_{Q^2=0} }$ can not be interpreted as the physically meaningful 3D root-mean-square axial radius of a spin-$\frac{1}{2}$ hadron. The genuine 3D root-mean-square axial radius in fact does not exist for any spin-$\frac{1}{2}$ hadron. We also show that the relativistic 3D weak-neutral spin radius $r_\text{spin} = \sqrt{\langle r_\text{spin}^2 \rangle}$, defined as $\langle r_\text{spin}^2 \rangle \equiv R_A^2 + \frac{ 1 }{ 4M^2 }\left[ 1 + \frac{ 2 G_P^Z(0) }{ G_A^Z(0) } \right]$ based on the relativistic and intrinsic 3D weak-neutral spin distribution in the Breit frame, is a physically meaningful radius that can be unambiguously defined for the nucleon. This provides an additional key motivation for the further determination of the induced pseudoscalar form factor $G_P^Z(Q^2)$, e.g. via lattice QCD or model calculations. Numerically, we find that $R_A \approx 0.6510~\text{fm}$ and $r_\text{spin} \approx 2.1054~\text{fm}$. For future experimental measurements of $G_A^Z(Q^2)$ and $G_T^Z(Q^2)$, we also derive the full tree-level unpolarized differential cross sections for neutrino-proton and antineutrino-proton elastic scattering in the lab frame, in hoping to provide a complementary and new perspective to unveil the nucleon spin structure by using (anti)neutrino-based facilities.

$B$ mesogenesis offers an interesting mechanism to generate the baryon asymmetry of the universe by converting the CP violation of the Standard Model into a net baryon number asymmetry. In this work we refine and extend the $B$ mesogenesis framework by incorporating all relevant $B$ meson channels active after low-temperature reheating. We first update the known neutral-meson contribution using time-integrated decay rates. While the $B_s^0$ contribution remains essentially unchanged, we find a suppression of the $B_d^0$ term by a factor $\sim 0.4$ with respect to previous analyses, alleviating the tension associated with its expected negative sign. We then perform a systematic study of $B_c^+$ decays, which are basically unexplored. We provide branching-ratio predictions using both leading-order factorization and a data-driven approach inspired by $D\to M_1M_2$ decays. These estimates allow us to quantify two $B_c^+$ sources of mesogenesis: the previously discussed $B_c^+ \to B^+ M^0$ channel and a new mechanism introduced in this work, $B_c^+ \to B_q^0 M$, in which the asymmetry is generated by combining direct CP violation with neutral-meson oscillations. Interestingly, in these channels the charm quark decays. Therefore, these decays give access to {\it charm CP violation} in modes with percent level branching ratios. With moderate assumptions, we find that $B_c^+$ mesogenesis can match or exceed the neutral contribution. Finally, we combine all three mechanisms and explore their viability in terms of the direct CP asymmetry, neutral-meson mixing parameters and early-universe fragmentation fractions. We find that successful baryogenesis can be achieved in a broad parameter space, showing the viability of $B$ mesogenesis. Future measurements of $B_c^+$ modes are thus highly anticipated to further probe the viability of unified $B$ mesogenesis.

We present a model-independent study of rare flavour-changing neutral current (FCNC) interactions of the top quark within the Standard Model Effective Field Theory (SMEFT). Matching a general top-FCNC parametrisation onto the SMEFT basis, we perform a global fit including low-energy flavour observables, electroweak precision data, Higgs measurements, collider limits on top-FCNC decays, and electric dipole moment constraints. Allowing for complex dipole operators, we derive stringent bounds on the real and imaginary parts of the top-FCNC couplings and, independently, obtain robust constraints on the corresponding SMEFT Wilson coefficients. We further provide predictions for rare top-FCNC branching ratios and CP asymmetries, and identify benchmark scenarios illustrating the complementary role of CP-violating observables in probing top-quark flavour dynamics.

Recent measurements of the CP asymmetry in the decay $D^0 \rightarrow K_S^0 K_S^0$ by the CMS collaboration, $A_{CP}(K_S^0 K_S^0) = (6.2 \pm 3.0 \pm 0.2 \pm 0.8)\%$, and by LHCb, $A_{CP}(D^0 \to K_S^0 K_S^0) = (1.86 \pm 1.04 \pm 0.41)\%$, suggest possible deviations from Standard Model (SM) expectations, which predict asymmetries below the percent level. This singly Cabibbo-suppressed decay is particularly sensitive to new physics, as the leading amplitudes vanish in the exact U-spin symmetry limit and the process is dominated by W-exchange topologies. We investigate scalar diquark contributions to this decay, comparing color-sextet and color-triplet representations. We find that the color-sextet diquark, characterized by a symmetric color structure $(C_1^{\mathrm{NP}} = C_2^{\mathrm{NP}})$, avoids color suppression and can generate CP asymmetries in the range $0.5\%$--$1.5\%$ for a diquark mass of order 1~TeV. In contrast, the color-triplet contribution is strongly suppressed due to destructive interference from its antisymmetric color structure. We further show that a flavor hierarchy in the sextet couplings, with $\lambda_{ud} > \lambda_{us}$, can simultaneously account for the observed deviation from the U-spin sum rule in $D^0 \to K^+ K^-$ and $D^0 \to \pi^+ \pi^-$ and the measured CP asymmetry in $D^0 \to K_S^0 K_S^0$. These results identify color-sextet scalar diquarks as viable candidates for explaining enhanced CP violation in charm decays.

We reassess a horizon-inspired description of quarkonium formation in jets, distinguishing momentum redistribution from loss of spin alignment. A normalized energy-sharing prescription, with benchmark inputs for the QCD string tension and quarkonium radii, softens specified $J/\psi$ and $\Upsilon(1S)$ fragmentation baselines without fitting their measured distributions. For the LO implementation displayed by LHCb, the mean momentum fraction changes from 0.629 to 0.476, compared with 0.452 in the prompt data. Applied to CMS-displayed PYTHIA bottomonium spectra, the same prescription produces shifts of the observed order, but neither comparison establishes agreement with the complete shape. An independent NLO bottomonium baseline already overestimates the low-fraction region, and an approximate acceptance-ordered application increases that excess. These results constrain the interpretation of an additional universal softening contribution. Momentum redistribution that preserves each event's spin matrix cannot change the fully integrated polarization. A separate $J/\psi$ formation-reweighting benchmark changes the polar anisotropy from 0.420 to 0.389; a larger reduction requires an additional spin-relaxation assumption. The earlier claim that the measured bottomonium fragmentation distribution establishes a resolution of the inclusive polarization puzzle is superseded. The remaining hypothesis is tested primarily through fragmentation in separately specified experimental phase spaces, with polarization as a conditional consequence.

We show that the Aligned 2-Higgs Doublet Model (A2HDM) is a framework able to simultaneously accommodate strong first order electro-weak phase transitions, in turn generating detectable gravitational waves as well as a variety of Higgs boson signals (involving both the Standard Model state and its companions, both neutral and charged) accessible at the Large Hadron Collider (LHC). We map the corresponding expanse of parameter space where such a phenomenology is realised in terms of the relative values of the masses of the discovered Higgs boson and the extended Higgs sector states of this model: two neutral ones (a CP-even and a CP-odd) plus a pair of charged ones. We find that both the Laser Interferometer Space Antenna experiment and High-Luminosity LHC can test such a scenario within their lifetime. This study thus sets the stage for a two-prong complementary approach able to scrutinise the extended Higgs sector of the A2HDM in both its high and low temperature manifestations.

The standard cosmological paradigm assumes that the inflaton field becomes dynamically negligible during the post-reheating evolution of the Universe. We demonstrate that this assumption fails for a broad class of inflationary models where the potential behaves as a monomial form $V(\phi) \propto \phi^k$ (with $k \ge 4$) around the minimum. In such scenarios, the effective inflaton mass depends on the field amplitude and vanishes asymptotically as the Universe expands. This vanishing-mass mechanism renders the inflaton kinematically accessible to the thermal plasma long after reheating, facilitating the regeneration of inflaton quanta through 1-to-2 decays and 2-to-2 scatterings of bath particles. This mechanism is quite generic and the coupling responsible for reheating can be constrained if the inflaton is overproduced, while the inflaton quanta can constitute dark matter in specific scenarios. Furthermore, if reheating occurs via the Standard Model Higgs portal, the process can be further constrained by big bang nucleosynthesis, cosmic microwave background, and colliders such as the LHC. This mechanism provides a new framework for probing post-inflationary reheating.

Dark matter search strategies have started advancing towards the neutrino fog. In this regard, compact objects such as neutron stars have already demonstrated their ability in probing such low DM-nucleon cross-sections from dark matter induced effects. In the optically thin limit, effect of dark matter self-interaction becomes relevant and may assist the capture and thermalization of dark matter inside stars, imparting observable changes on neutron star temperatures. The resulting radiation although weak can be potentially detected by the James Webb Space Telescope and upcoming Thirty Meter Telescope and the European Extremely Large Telescope. Observation of cold neutron stars accompanied by advancements in direct detection probes would provide stringent constraints or a smoking-gun signature for dark matter self-interactions. The potential detection of a neutron star with surface temperatures $\sim (1000 - 1200)$ K in the optically thin limit can push the bounds on asymmetric dark matter self-interaction cross-section to approximately two orders of magnitude more stringent than the bullet cluster.

We propose an explanation for the dark matter-baryon coincidence based on collapsing $\mathbb{Z}_N$ domain walls, which form a novel compact baryonic state: the baryoid. A baryoid has an asteroid-scale mass and up-to-nuclear-scale energy density, and can serve as a dark matter candidate. Starting from equal baryon numbers in the domains formed in the early universe, the collapse of the domain walls after the QCD phase transition leads to a baryon-number ratio of $(N-1):1$ between the false- and true-vacuum domains. Since baryons are slightly lighter in the false-vacuum domains than in the true-vacuum domain, the resulting dark matter-to-baryon energy-density ratio is naturally close to, but slightly smaller than, $(N-1):1$, or $6:1$ for $N=7$. We calculate the domain-wall dynamics and the efficiency of baryon-number trapping, derive the resulting baryoid properties, and discuss a broad set of phenomenological probes.

The spectrum of vector charmonium(-like) states in the 4.1\dash4.6~GeV energy region exhibits a long-standing tension between inclusive and exclusive measurements. While the inclusive $R$-value indicates only conventional vector charmonia such as $\psi(4160)$ and $\psi(4415)$, exclusive $e^+e^-$ cross sections reveal additional structures whose parameters strongly depend on the observed final states when fitted with Breit--Wigner functions. This puzzling pattern suggests that coupled-channel and threshold effects play an essential role. In this work, we develop a unified coupled-channel framework for the $1^{--}$ resonances in this energy region. The framework incorporates the $S$-wave open-charm channels $D\bar{D}_1$, $D^*\bar{D}_1$, and $D^*\bar{D}_2^*$ constrained by heavy-quark spin symmetry, optional bare poles associated with $\psi(4160)$ and $\psi(4415)$, and final-state interactions in the $Z_c$ channels. We perform simultaneous fits to the BESIII cross sections for $e^+e^-\to J/\psi\pi^+\pi^-$, $h_c\pi^+\pi^-$, $D\bar{D}^*\pi$, $D^*\bar{D}^*\pi$, $J/\psi\eta$, and $\chi_{c0}\omega$, together with invariant-mass distributions exhibiting the $Z_c(3900)$ and $Z_c(4020)$ structures. The benchmark models differ in the number of bare seed states and the fitting strategy. We show that even the purely dynamical scheme without bare charmonia captures the gross features of the analyzed distributions. The inclusion of bare compact states improves the fit quality but does not change the conclusion that the measured line shapes can be understood in terms of strong coupled-channel effects with dynamically generated poles. We also discuss possible heavy-quark spin partners of the exotic $1^{--}$ states.

Broad claims have been made over years about achievement of quark-gluon plasma (QGP) formation in high-energy heavy-ion collisions based on certain phenomena anticipated for QGP formation. More recently, similar phenomena have appeared in smaller collision systems. In response, the original narrative associated with QGP formation has been altered, with introduction of novel concepts such as ``QGP droplets'' appearing even in p-p collisions. In contrast, alternative research has revealed novel aspects of p-p and p-Pb collisions such as exclusivity for N-N interactions and consequences of time dilation for interacting partons. Collision geometry for A-B collisions has also been shifted from conventional Glauber Monte Carlo simulations (strongly biased) to inversion of ensemble-mean $\bar p_t$ data. The present study demonstrates that jet production dominates all aspects of $p_t$ spectrum structure and minimum-bias angular correlations over the full $p_t$ range of accessible data. Recently, progress has been made on interpretation of azimuth quadrupole ($v_2$) data, reexpressed in terms of total correlated-pair number as an extensive measure, leading to inference of quadrupole $m_t$ spectra and quadrupole amplitude variation across all A-B collision systems that show strong indication of the effects of exclusivity. The same approach applied to jet angular correlations shows similar trends. A comprehensive quantitative description of the two QCD phenomena across all collision systems has emerged. The underlying processes are few-gluon interactions producing characteristic correlation structures corresponding to color-dipole (two-gluon, dijet) and color-quadrupole (three-gluon) radiation. That description does not rely on any role for a dense medium, multiple scattering, QGP droplets or hydro theory. It applies the same rules uniformly to small and large collision systems.

The proposed ANUBIS detector has been designed to search for Long-Lived Particle (LLP) signatures, which have become a focus for a variety of experiments within recent years. Due to the variety of possible LLP models and the need for directly comparable sensitivity results highlighting the potential coverage of ANUBIS, the SET-ANUBIS (Simulation, accEptance and sensiTivity studies framework for ANUBIS) framework has been developed. SET-ANUBIS is a flexible open-source Python framework that can perform full sensitivity studies of LLP signatures for the ANUBIS detector, allowing others to directly produce ANUBIS-like limits or even implement other geometries and detectors. It starts from a Universal FeynRules Output model or user-supplied rates; it exposes model parameters and particle content for user modification, and evaluates decay widths, branching ratios and lifetimes. MARTY can also be used to compute matrix elements, decay widths, branching ratios, and cross-sections. Then the framework prepares or runs event generation through Pythia8 or MadGraph, ingests HepMC event records, models the geometry of the ATLAS cavern and ANUBIS tracking stations, and applies a configurable sequence of geometric, kinematic and isolation requirements to select a set of surviving LLP candidates for evaluation. The implementation follows a ports-and-adapters architecture so that the core logic remains separate from external generators, persistent storage and visualisation. A scan-aware SQLite catalogue and content-addressed store preserve cards, metadata and compact selection-ready event bundles while avoiding duplicate artifacts. A pre-release version of the SET-ANUBIS framework has already been used to successfully derive the sensitivity of ANUBIS to three LLP benchmark models involving a Higgs portal and a Heavy Neutral Lepton model.

We show that the ionization of molecular clouds provides a novel probe of dark matter scenarios producing low-energy $e^+e^-$ pairs through annihilation, decay, or Hawking evaporation of primordial black holes. We derive constraints on MeV-scale dark matter with masses between $\sim1$ and $100$ MeV, as well as on primordial black holes in the mass range $10^{14}$--$3\times10^{17}$g. By modeling the propagation of electrons and positrons inside molecular clouds, we show that uncertainties in charged-particle transport constitute the main limitation of this method. Nevertheless, for the most physically motivated propagation scenarios, the resulting constraints remain competitive with the strongest bounds currently available. We also identify the molecular-cloud properties that maximize the sensitivity to dark matter-induced ionization and discuss how larger samples of clouds, together with improved modeling of cosmic-ray ionization and cloud structure, could substantially enhance the reach of this technique. Our results establish molecular-cloud ionization as a promising and complementary probe of sub-GeV dark matter and evaporating primordial black holes.

Calculating cross sections in the Color Glass Condensate effective theory requires Fourier transforms of multi-Wilson-line correlators from transverse coordinate space to transverse momentum space. Under the common assumption of impact-parameter independence, each transform reduces to a set of Hankel transforms whose Bessel-function kernels oscillate rapidly at phenomenologically relevant momenta, making direct quadrature prohibitively expensive. We present a Filon-type quadrature, applicable to any integrand, that integrates these oscillatory factors in closed form on the stored coordinate grid, reducing each Hankel transform to a precomputed weight vector and the full nested transform chain to a sequence of matrix products. We develop and validate the method on the deep inelastic scattering dijet cross section beyond the correlation-limit approximation, where an exprel-based reformulation of the quadrupole Wilson-line correlator removes a numerical $0/0$ instability inherent to its standard parametrization. Porting the calculation to the Graphics Processing Unit (GPU), with custom CUDA kernels that fuse the momentum-space contraction directly into the correlator evaluation, brings the runtime for one dipole input down to about two minutes on a single NVIDIA A800, from several hours on a multi-core Central Processing Unit (CPU). We further generalize the algorithm to three sequential Hankel transforms and validate the resulting six-dimensional transform against an analytic Gaussian integrand family with closed-form results at every stage. This general, process-independent algorithm is directly applicable to next-to-leading-order proton-nucleus and electron-ion scattering cross-section calculations performed without the correlation-limit approximation. The code is publicly available at this https URL.

This article proposes a dynamical framework to address the charged-lepton mass hierarchy and derive the empirical Koide formula. We postulate a $U(3)_F$ flavor symmetry at the high-energy scale, where a heavy dynamical flavon field couples to the electroweak Higgs sector via an effective operator. As the universe cools, spontaneous symmetry breaking of the flavor group occurs following the pattern $U(3)_F \to U(1)^3_F$. Subsequently, the electroweak symmetry breaking at the Fermi scale generates the charged-lepton mass matrix. The phenomenological values of these masses are determined in the infrared regime, where the effective potential governing the flavon VEV undergoes a dynamical vacuum this http URL stable minimum of this potential enforces an algebraic equipartition between the flavor-singlet and flavor-octet invariants ($I_{(0)} = I_{(8)}$). This geometric equilibrium yields the Koide mass ratio ($Q=2/3$), successfully identifying the dynamically generated eigenvalues with the physical pole masses of the electron, muon, and tau.

LUX-ZEPLIN (LZ) has reported one event compatible with a $248~\mathrm{keV}$ nuclear recoil. While initial attention has focused on inelastic dark matter, that interpretation depends sensitively on the uncertain high-speed tail of the Galactic halo. We develop instead an elastic realisation of the pseudoscalar-pseudoscalar interaction $L_4=(\bar\chi i\gamma^5\chi)(\bar N i\gamma^5N)$, whose contact templates give one of the largest local significances identified by LZ. The minimal model presented involves Dirac fermion dark matter and a pseudoscalar mediator. The pseudoscalar arises from a complex singlet and the minimal gauge-invariant UV completion also requires a single multi-TeV vector-like heavy quark. A representative model which realises thermal freeze-out has $m_\chi\sim 400~{\rm GeV}$ and $m_a\sim 1~{\rm GeV}$. The simplest model breaks from the isoscalar/isovector assumption, and the recoil spectrum lies between LZ's elastic $O_4^v$ and contact $L_4^v$ templates, suggesting a local significance of $2.6$-$3.2\sigma$.

The LUX-ZEPLIN (LZ) Collaboration has reported a $248$ keV nuclear-recoil candidate for which endothermic dark matter (DM) gives some of the largest local significances. We study Solar-capture constraints on three interpretations: a thermal Higgsino, a thermal pseudo-Dirac fermion with off-diagonal vector interactions, and neutron-philic endothermic spin-dependent scattering through $\mathcal{O}_4$. The canonical full-density thermal Higgsino is excluded: its LZ-preferred splitting near $0.38\,\mathrm{MeV}$ lies well below the splitting required to suppress Solar capture sufficiently to satisfy the IceCube upper limits on DM annihilation in the Sun, $\delta\gtrsim0.51$-$0.56\,\mathrm{MeV}$. For the pseudo-Dirac benchmark parameters that fit the LZ event, we find $C_\odot=1.53\times10^{20}\,\mathrm{s}^{-1}$, while two-state kinetics limits the fixed-orbit annihilation rate to $\Gamma_A\lesssim4.4\times10^{14}\,\mathrm{s}^{-1}$, about $1.7\times10^5$ below the IceCube upper limit for the $b\bar b$ channel. A semi-analytic treatment indicates that re-excitation cycles further cool the captured population, although a full phase-space calculation is required for its final distribution. For neutron-philic $\mathcal{O}_4$ scattering at $m_\chi=1$ TeV and $\delta=300$ keV, finite-temperature capture gives $C_\odot=3.98\times10^{17}\,\mathrm{s}^{-1}$, with nuclear-structure uncertainties giving an envelope $(1.77$-$9.72)\times10^{17}\,\mathrm{s}^{-1}$. Under the equilibrium assumption, the upper edge remains about a factor $154$ below the IceCube upper limit for the $b\bar b$ channel. We use $b\bar b$ only as a soft-hadronic proxy because an exact constraint requires the model-specific annihilation spectrum. Solar capture therefore excludes the thermal-Higgsino interpretation but not endothermic explanations generically.

Protons and neutrons differ dramatically in their electromagnetic sizes, but are bound by the strong (color) force and have nearly identical masses, like two twin states of the same ``nucleon". To reveal the overall spatial extent, it must be examined through the strong interaction rather than electromagnetism. The $J/\psi$ particle, a compact color-charge dipole of a charm quark and antiquark, provides an ideal probe. Recent high-precision measurements of near-threshold $J/\psi$ production at Jefferson Lab offer a more precise glimpse of the proton's gluonic spatial structure. Combining these data with recent quark-sector results, we extract the distribution of the color field underlying mass generation in the nucleon and find it extends beyond both charge and mass distributions, revealing the nucleon's overall strong-interaction spatial extent of $0.94\pm 0.09$ fm.

Hadronic transport approaches used in heavy-ion collision simulations rely on a consistent and accurate hadron list with decay channels. Hadron lists in common use are often experimentally outdated, or, as with the Particle Data Group (PDG) compilations, incompatible with transport codes without further adaptation. We construct PDG2021+, an updated hadron list including all states from the 2021 Particle Data Booklet, together with a binary-decay list designed for direct use in the SMASH transport framework. Using the hadron resonance gas model, we validate the PDG2021+ list against lattice quantum chromodynamics results and experimental yield data. We show that employing $1 \to 2$-body decay chains as a proxy for the full decay processes has a suppressing effect in the low-$p_T$ region of the pion spectrum and introduces a $\sim 3\%$ systematic uncertainty in the pion $\langle p_T \rangle$. Moreover, the inclusion of additional states in PDG2021+ further shifts the pion $\langle p_T \rangle$. These result establish PDG2021+ as a robust, transport-ready hadron list and quantify the systematic effects of decay modeling on key heavy-ion observables.

We present a lattice-QCD calculation of the masses and decay constants of the positive-parity heavy-strange mesons $D^*_{s0}$, $D_{s1}$, $B^*_{s0}$, and $B_{s1}$. The calculations are performed with domain-wall fermions for the light and strange quarks and an anisotropic clover action for the charm and bottom quarks. We use seven different RBC/UKQCD ensembles with pion masses ranging from a near-physical 139 MeV up to 431 MeV. We consider two different analysis types, with or without two-meson operators at the source. We observe the expected below-threshold ground states. The fits without the two-meson operators appear to be more stable, but may overestimate the ground-state energies, while preliminary fits with two-meson operators at the source only appear to underestimate the ground-state energies.

We present a microscopic model of the dark sector that resolves the Hubble tension within standard current data sets (Planck 2018, Pantheon+ and DESI DR2 BAO) based on well-known fundamental principles, gauge symmetry and spontaneous symmetry breaking. It builds on the Hot New Early Dark Energy (Hot NEDE) setup, featuring a dark $SU(N)$ gauge symmetry broken to $SU(N-1)$ in a supercooled phase transition that creates a thermal bath of self-interacting dark radiation in the epoch between Big Bang Nucleosynthesis and recombination. Adding a fermion multiplet charged under the gauge symmetry provides a naturally stable component of dark matter that interacts with dark radiation. Spontaneous symmetry breaking predicts a decoupling of this interaction once the dark sector cools down, that we refer to as dark radiation matter decoupling (DRMD). We also provide a simplified DRMD model that captures the essential features of the full theory while retaining additional falsifiable predictions. Using the data sets stated above, we find agreement with the SH${}_0$ES determination of $H_0$ at the 1.4$\sigma$ level, compared to a 5.7$\sigma$ tension in $\Lambda$CDM, thereby providing a resolution of the Hubble tension.

Topological defects that form in a nonequilibrium second-order phase transition are presumably seeded by fluctuations of the order parameter in the vicinity of the critical point. Motivated by this conjecture that underlies the Kibble-Zurek mechanism (KZM), we investigate whether machine learning (ML) can anticipate their locations from the fluctuations in the ``impulse regime'', the time interval when the evolution of the order parameter cannot keep up with the conditions imposed by the quench. Going beyond the conventional KZM focus on defect density, we show that a recurrent neural network can predict locations of topological defects from short-time dynamical data deep within the impulse regime. We thus demonstrate that defects are sown in the immediate vicinity of the critical point. The seeds of defects, fluctuations imprinted on the evolving order parameter, are exponentially small near the critical point, but become amplified by the evolution and play a dominant role in breaking symmetry. This is before the freezeout time that concludes the impulse regime, and well before the order parameter assumes its final symmetry-broken configuration. Furthermore, we find that the predictive power of the ML also exhibits power-law scaling consistent with KZM.

DESI DR2 data have been widely interpreted as evidence for late-time evolving dark energy (DE) with an apparent phantom crossing. Here we investigate an alternative explanation, based on early-Universe physics. If dark acoustic oscillations (DAO) are close in scale to baryon acoustic oscillations (BAO), they can bias the extraction of the BAO scale from the peak in the galaxy correlation function. This leads to an apparent shift in the inferred distance if the superposition of BAO and DAO features is misinterpreted as being due to BAO only. Taking this shift into account, we find that a DAO with percent-level amplitude can reconcile DESI DR2 with Planck 2018 as well as Pantheon+ supernovae data, with fit improvement at a similar level compared to evolving DE. Notably, a DAO feature with the required properties has been predicted in a previously proposed scenario that resolves the Hubble tension via a pre-recombination decoupling of dark matter and dark radiation (DRMD). The presence of a DAO feature close to the BAO peak can be scrutinized with future full-shape galaxy clustering data from DESI and Euclid.

We phenomenologically derive a cosmological model that includes both a cosmological constant term $\Lambda/3$ and a dissipative driving term $\beta (2 H^{2} + \dot{H})$ by applying both the first law of thermodynamics and an effective entropy (that is proportional to the Bekenstein--Hawking entropy) to matter creation cosmology. Here $H$, $\dot{H}$, and $\beta$ are the Hubble parameter, the time derivative of $H$, and a non-negative dimensionless coefficient used for the effective entropy, respectively. The dissipative term is proportional to the Ricci scalar curvature, suggesting that the dynamic creation pressure has the same dependence. We examine the model's background evolution in the late universe and its horizon thermodynamics. The present model supports a transition from a decelerating universe to an accelerating universe when $\beta <0.5$.The second law of thermodynamics is always satisfied on the horizon, and maximization of entropy is satisfied in the final stage. In addition, we study first-order density perturbations related to structure formation, by applying a neo-Newtonian approach to the present model. We then examine constraints on the present model using three types of observational data and the transitional and thermodynamic constraints and find that a weakly dissipative universe with $\Lambda$ is likely favored and consistent with our Universe. We also discuss irreversible entropy due to adiabatic particle creation, assuming a holographic-like matter creation cosmology.

We construct and classify asymptotically flat, static, and spherically symmetric hairy black hole solutions in $U(1)$ gauge-invariant scalar-vector-tensor (SVT) theories carrying both electric and magnetic charges. Extending previous analyses restricted to ${\cal L}_{\rm SVT}^{2}$, we incorporate the cubic and quartic SVT sectors, ${\cal L}_{\rm SVT}^{3}$ and ${\cal L}_{\rm SVT}^{4}$, respectively. At the covariant level, the quartic SVT sector can generate higher-order derivatives, and we derive a condition that removes them before specializing to dyonic backgrounds, where they are generically present. We then classify the scalar hair according to the symmetry of the theory. In shift-symmetric theories, horizon regularity together with Noether-current conservation determines the scalar charge in terms of the remaining solution parameters, corresponding to secondary hair. When the couplings depend explicitly on the scalar field $\phi$, independent scalar integration constants appear in the asymptotic solutions, allowing branches with primary hair. We also find that the magnetic charge activates the $\tilde f_3$ interaction in the cubic SVT sector, which does not contribute in purely electric static and spherically symmetric configurations, thereby producing hairy solutions supported by the magnetic charge. The scalar field also exhibits interaction-dependent asymptotic falloff rates. Combining these expansions with numerical integration, we connect the near-horizon and asymptotic regimes for all branches in the cubic sector and for one of the two quartic branches. For the remaining quartic branch, our result is restricted to the local near-horizon expansion.

Primordial Black Holes (PBHs) forming prior to Big Bang Nucleosynthesis evolve during the reheating epoch, an environment dominated by an oscillating inflaton field decaying into a relativistic thermal bath. In this work, we track the complete lifecycle of PBHs within this coupled inflaton-radiation background. Utilizing $\alpha$-attractor E-models, we analytically anchor the reheating initial conditions directly to Cosmic Microwave Background observations. By matching exact scalar field solutions in a Schwarzschild spacetime to the cosmological far-zone, we derive the cycle-averaged mass accretion rate and couple it to the growing radiation bath. We find that this combined accretion induces a highly non-linear enhancement of the final PBH mass. Because the Hawking evaporation timescale scales cubically with mass, PBHs forming near their critical runaway limits experience a massive extension of their lifespans. Surviving deeper into the radiation-dominated era triggers a multi-order-of-magnitude amplification in their emitted Stochastic Gravitational Wave Background (SGWB).

The goal of this work is to describe the scale invariant solutions of a typical relativistic hydrodynamic model. We shall take as representative model an Israel-Stewart framework, where the energy-momentum conservation laws for a conformal invariant fluid are supplemented by a Cattaneo-Maxwell equation for its viscous energy-momentum tensor. In these models the viscous energy-momentum tensor relaxes to its Landau-Lifshitz value on a finite time scale. We assume the parameters of the model depend on the speed of light $c$ in such a way that as $c\to\infty$ the fluid becomes an incompressible fluid obeying the Navier-Stokes equations. We seek the scale invariant solutions for this model and find that for finite $c$ there are two basic patterns, one which reproduces Kolmogorov turbulence when $c\to\infty$, and another whose damping rate diverges in that limit. We point out the scaling relations that allow the latter flow pattern to sustain an entropy cascade.

I investigate the low-energy scattering and femtoscopic correlation functions of the $d-\Lambda$, $d-\Sigma$, and $d-\Xi$ systems within a microscopic folding approach. The effective deuteron--hyperon interactions are constructed by folding the HAL-QCD hyperon--nucleon potentials with the deuteron wave function, while the spin and isospin structures are treated through Wigner-$6j$ recoupling coefficients. Using the resulting interactions, I calculate the scattering parameters and momentum correlation functions for all spin channels. No bound states are found for the $d-\Lambda$, $d-\Sigma$, or $d-\Xi$ systems. Nevertheless, the $d-\Lambda$ correlation exhibits a pronounced low-momentum enhancement associated with a large scattering length and a near-threshold pole, whereas the $d-\Sigma$ correlation is suppressed by its predominantly repulsive interaction. The neutral $d-\Xi^{0}$ system shows only a moderate enhancement, while the charged $d-\Xi^{-}$ correlation is strongly amplified by the attractive Coulomb interaction. I further investigate feed-down effects from $\Sigma^{0}$, $\Sigma(1385)$, and $\Xi$ decays using Monte Carlo response matrices and demonstrate that these decays clearly modify the observable $d-\Lambda$ correlation. The results provide quantitative predictions for future femtoscopic measurements and establish deuteron--hyperon correlations as a sensitive probe of hyperon--nucleus interactions.

We give the next-to-next-to-leading order color-singlet BFKL eigenvalue of planar N=4 super Yang-Mills at odd conformal spin n in closed form. At the two lower orders the known expressions contain nested harmonic sums only at the two conjugate points z=(|n|-1)/2+i nu and zbar. At three loops the sums are evaluated on a ladder of integer-shifted arguments from the reflected point -zbar up to z, with one point past it, the coefficient at a rung fixed by its two distances to the ends. Seven families are the exception, their coefficients written through ladder sums whose summand shifts with the summation index. For one of the seven the coefficient lies outside the fixed-coefficient algebra of nested harmonic sums of the two distances, an arithmetic obstruction in the denominators. That exclusion reaches the eigenvalue coefficient only through an agreement of rule and coefficient verified and not proved. Rules uniform in the conformal spin produce all forty-seven families at every odd n>=3; no per-spin coefficient is tabulated in the closed form, and the n=1 boundary block is supplied separately. Those rules are a reconstruction from the computed spins, exact at every one of them, verified over the range n<=99 and at the holdout spin n=101, and not proved at arbitrary odd n. Each atom-table coefficient is a rational combination of 1, pi^2 and zeta_3, coefficient and atom together carrying transcendental weight five. Along nu=0 the intercepts match the Quantum Spectral Curve values at each computed odd spin through n=91, the extent of those values. The comparison tests the integrand and the reduction together at one point of each spin, for most of them for the first time. Away from that line the closed form gives the collinear behavior of the block uniformly in the spin, which the intercepts alone do not fix.

The asymptotic symmetry group of asymptotically flat spacetimes gives rise to balance flux equations that constrain, fully non-perturbatively, the asymptotic strain measured by gravitational-wave detectors. Such constraints are sharp tools for identifying features such as the memory effect. As detector sensitivities improve, it becomes imperative to place the most promising beyond-GR candidates on the same footing. Whether the asymptotically flat framework applies to such theories at all is far from obvious and requires careful analysis of the additional degrees of freedom reaching future null infinity. In this work, we address this question. We integrate the Bondi-Sachs hierarchy in the presence of an arbitrary stress-energy tensor and extract the falloff conditions its components must satisfy for the standard metric decay to close. We then feed the most general scalar-vector-tensor (SVT) theory with second-order equations of motion through this framework. Recasting the field equations in the effective Einstein form $G_{\mu\nu}=T^{\rm eff}_{\mu\nu}/G_4(\Phi,X)$ and evaluating every operator in the SVT Lagrangian against the falloff table, we condense the outcome into a constraint table for the coupling functionals and their derivatives at the asymptotic vacuum, sharpened by the additional equations of motion and vacuum stability. Remarkably few conditions survive. The scalar potential must vanish to cubic order at the asymptotic vacuum, the asymptotic Newton constant must be finite and positive, the scalar and vector modes must be canonically normalized, and the conformally coupled sector carries a frame subtlety. Every other coupling functional is protected by the theory's structure. The constraint table thus provides a diagnostic for screening beyond-GR models against asymptotic flatness and establishes the BMS group as the asymptotic symmetry group across the entire SVT class.

The combination of cosmic microwave background (CMB) measurements with distance measurements from baryon acoustic oscillations (BAO) and type Ia supernovae (SNIa) suggests that dark energy is dynamical, with an equation of state crossing the phantom divide at low redshifts. This feature can not be described within canonically normalized, minimally coupled, self-interacting scalar field models. We investigate the possibility of achieving phantom crossing by introducing an interaction in the dark sector such that the dark matter particle mass is dependent on the dark energy field $\phi$ as $m \propto \phi^\alpha$. We consider a self-interacting potential of the inverse power-law form $V \propto \phi^{-\beta}$. We implement this model both at the background and perturbative levels in a Boltzmann solver and use a bayesian framework to constrain its parameters using using CMB, BAO and SNIa data. We find best-fits that have similar goodness-of-fits as the commonly used phenomenological $w_0-w_a$ parameterization, providing a more fundamental understanding of the dark sector.

The dipole model provides a powerful framework for describing high-energy nuclear interactions, particularly in the regime of dense gluonic matter. However, accurately evolving the dipole--nucleus scattering amplitude remains a major computational challenge because it is governed by nonlinear QCD evolution equations. To address this, we investigate a machine learning (ML) model as an efficient surrogate for the conventional numerical evolution. These ML-based approximations dramatically reduce the computational cost of global analyses while maintaining the accuracy required to describe a broad range of experimental data. We systematically evaluate the ML results for accuracy, computational efficiency, and ability to capture essential features of dipole evolution in nuclear environments. These computational advancements will enable global analyses of diverse datasets within both the dipole and parton model frameworks, providing a more rigorous probe of nuclear structure in the dense regime. Comparing both descriptions within a common fitting framework can provide precise constraints on the gluon distributions and advance our understanding of the quark and gluon structure of nuclei, particularly in the small-x region.