Wed·May 13, 2026Wednesday·May 13, 2026

1. 01*

   Two-loop neutrino mass model with modular $S_4$ symmetry

   A. E. Cárcamo Hernández🇨🇱 · J. Echeverria-Puentes🇨🇱 · Vishnudath K. N.🇨🇱 · Sergey Kovalenko🇨🇱 · Daniel Salinas-Arizmendi🇦🇲 · Carlos A. Vaquera-Araujo🇲🇽

   We propose a two-loop radiative neutrino mass model based on the modular ${\Gamma }_4\simeq S_4$ flavour symmetry supplemented by a discrete $Z_3$ symmetry. After spontaneous modular symmetry breaking, a remnant $Z_2$ symmetry guarantees both the radiative origin of active neutrino masses and stabilizes dark matter candidates. The model successfully reproduces charged lepton masses and neutrino oscillation data for normal ordering. It also predicts observable rates for charged lepton flavour violation (LFV). Due to the singlet-doublet mixing the model provides a viable scalar dark matter candidate. A fermionic dark matter candidate, strongly linked to LFV, is also present. We identify parameter regions consistent with relic density, LFV constraints, and direct detection limits, providing testable benchmark configurations.

   hep-ph0 citations
2. 02*

   Connecting Neutrino Masses, Dark Matter and Leptogenesis from $\Delta (54)$ Flavor with Triple Inverse Seesaw

   H. Bora🇮🇳 · N. Bharali🇮🇳 · R. Sarkar🇮🇳 · S.K. Jha🇮🇳 · A. Baruah🇮🇳 · Ng.K. Francis🇮🇳

   In this present study, an extended Delta 54 flavor symmetry model incorporating two standard model Higgs doublets is investigated. This model generates neutrino masses through the triple inverse seesaw mechanism. It predicts deviations from tribimaximal mixing, yielding a nonzero reactor angle and an atmospheric mixing angle in the upper octant. In addition, the CP-violating phase and the Jarlskog invariant are found to be consistent with current neutrino oscillation data. Our study also includes the dark matter sector by evaluating the relic abundance and active neutrino dark matter mixing under relevant cosmological constraints. Furthermore, baryogenesis is achieved through resonant leptogenesis at the TeV scale including flavor effects. We obtain the observed baryon asymmetry, for right-handed neutrino mass 10 TeV and mass splitting d.

   hep-ph0 citations
3. 03*

   An approximate formula for the entropy of the negative binomial distribution

   Sándor Lökös🇵🇱

   Recent theoretical developments revived the interest in charged particle multiplicities and their wide-spread parametrization, the negative binomial distribution (NBD). The central observable of the studies is the Shannon entropy of the NBD. A closed form is not known, however, there are representations with special series and integrals. In this note, we will investigate one of these and give an approximate formula for the entropy that is valid up to $\sim$20\% deviation from the exact value for extreme values of the NBD parameters.

   hep-ph0 citations
4. 04*

   Gluon Entanglement Entropy inside a Nucleon: A Toy Model

   David Horn · Berndt Müller🇺🇸 · Xiaojun Yao🇺🇸

   We construct a toy model of a nucleon, in which three static quarks interact via a SU(3) gauge field on a planar honeycomb lattice. The dynamics of the gauge field is described by the Kogut-Susskind Hamiltonian, truncated to the lowest three SU(3) irreducible representations. We show that the internal structure of the toy nucleon reflects salient features of the physical nucleon state. We then find the entanglement entropy of the gauge field within the nucleon state and compute its time evolution after a quench, in which all three valence quarks are suddenly removed. We show that the entanglement entropy in the final state is dominated by the dynamically generated contribution rather than the initial state entropy.

   hep-phnucl-th3 citations
5. 05*

   Absorption of Gravitons and Photon Luminosities of Interstellar/Intergalactic Hydrogen Atoms

   George Savvidy🇬🇷 · Pavlos Savvidis🇨🇳

   We compute the emission and absorption rates of gravitons by hydrogen atoms. The absorption rate of gravitons is proportional to the number of hydrogen atoms and to the graviton luminosity. The number of hydrogen atoms in interstellar/intergalactic media can be large while the graviton luminosity of Sun, or a typical star, is in the eV to keV range that well overlaps with the resonance frequencies of the hydrogen atoms. Currently, the observational knowledge of the graviton luminosity in different regions of the Universe is limited, and here we will consider its value as unknown quantity that should be determined by independent astrophysical observations. We suggest measuring the ratio of the photon luminosities from interstellar/intergalactic hydrogen atoms that can provide information concerning the luminosity of gravitons in different regions of space. This ratio maximally exposes the fundamental physical nature of photons and gravitons - their helicity, which is one for the photons and two for the gravitons. The ratio is sensitive to any sources of gravitational radiation and provide a possible method for measuring their radiation intensities.

   hep-phastro-ph.COastro-ph.GAgr-qc0 citations
6. 06*

   Reviving primordial black hole formation in slow first-order phase transitions

   Wen-Yuan Ai🇨🇳 · Ke-Pan Xie🇨🇳

   Large curvature perturbations generated during slow first-order phase transitions are a promising source of primordial black holes. However, recent analyses suggested that the mechanism is ruled out once the density contrast and the formation threshold are evaluated in the same gauge. In this work, we show that this mechanism remains viable: after a supercooled transition, reheating can be sufficiently slow that the Universe enters an early matter-dominated era, during which even small overdensities grow and collapse into primordial black holes.

   hep-phastro-ph.COgr-qc7 citations
7. 07*

   Long-lived sterile neutrinos from axionlike particles at the Super Tau-Charm Facility

   Xiaokun Li🇨🇳 · Zeren Simon Wang🇨🇳 · Yu Zhang🇨🇳 · Xiaorong Zhou🇨🇳

   We study the search prospect of long-lived heavy neutral leptons (HNLs) pair produced in decays of axionlike particles (ALPs) at the proposed Super Tau--Charm Facility (STCF), focusing on the center-of-mass energy of $\sqrt{s}=3.773$ GeV. The ALPs are assumed to originate from $D^{\pm }$-meson decays in association with a charged pion. We perform both truth-level and detector-level Monte Carlo simulations and obtain the expected sensitivity reach to the mixing parameter between the HNL and the electron neutrino, $|V_{eN}{|}^2$, with a displaced-vertex search at STCF. We find that STCF can probe values of $|V_{eN}{|}^2$ about one-to-two orders of magnitude beyond the existing bounds. We also perform an approximate reinterpretation of a search for HNLs at the CHARM experiment, which is subject to model-dependent assumptions on the production and kinematic distributions, and find that beam-dump experiments may provide strong complementary constraints.

   hep-phhep-ex0 citations
8. 08*

   SMEFT everywhere: a NLO study of $\mathbf{pp}\to \mathbf{t}\bar{\mathbf{t}}\mathbf{H}$ with decaying tops

   Giuseppe Bevilacqua🇬🇷 · Minos Reinartz🇩🇪 · Malgorzata Worek🇩🇪

   We present the computation of the next-to-leading order QCD corrections to the $pp\to t\bar{t}H+X$ process in the di-lepton channel at the LHC, including relevant dimension-6 operators $({\mathcal{O}}_{t\varphi },{\mathcal{O}}_{\varphi G},{\mathcal{O}}_{tG},{\mathcal{O}}_{tW})$ from the Standard Model Effective Field Theory. In our studies, higher-order corrections and effective operators are consistently included in the production part of the process as well as in the top-quark decays. We perform a detailed study of linear, cross, and quadratic contributions and their uncertainties, including renormalisation group effects. Our findings are presented at the integrated and differential cross-section level for the LHC Run III center-of-mass energy of $\sqrt{s}=13.6$ TeV. Finally, we provide predictions for $pp\to t\bar{t}H+X$ with stable top quarks and compare them with the results in which top quarks are reconstructed from their decay products. We show that kinematic cuts, as well as higher-order effects and SMEFT operators in top-quark decays, are important and should be consistently considered together, because they have a significant impact on the shape of the standard observables measured for the $pp\to t\bar{t}H+X$ process at the LHC.

   hep-phhep-ex1 citation
9. 09*

   In-medium Y(1S,2S,3S) suppression in Pb-Pb collisions at sqrt(s_NN)=5.02 TeV

   J. Majonica🇩🇪 · G. Wolschin🇩🇪

   We present model calculations for the in-medium suppression of the Y(1S,2S,3S) states in sqrt(s_NN)=5.02 TeV Pb-Pb collisions at the Large Hadron Collider in comparison with recent CMS data for all three spin-triplet s-wave states. The model parameters initial central temperature, and formation times for the Y(nS) states are determined in simultaneous chi^2 minimizations with respect to the data, such that the sequential centrality- and transverse-momentum-dependent suppression of the observed states is reproduced.

   hep-phnucl-thNPB 1028, 117510 (2026)·0 citations
10. 10*

    Formulation of parton shower evolution beyond leading order for electron-positron annihilation

    Zoltan Nagy🇩🇪 · Davison E. Soper🇺🇸

    Parton shower evolution is given by a renormalization group equation that reflects the infrared behavior of perturbative QCD including color and spin and including quantum interference. With added approximations, such an evolution equation can provide the basis for a parton shower event generator. To date, splitting functions for parton shower evolution have been derived only to leading order in $\text{as}$. We provide a framework that can provide splitting functions beyond leading order, and in particular at order ${\text{as}}^2$. This requires a representation of Feynman graphs in which partons are off shell and are characterized by vector or spinor indices instead of on-shell spins.

    hep-ph0 citations
11. 11*

    Trace anomaly, effective degrees of freedom, and chemical potential effects near the QCD crossover

    Yaroslav Krivenko-Emetov🇦🇹

    A compact analytical scheme is presented for describing ultra-dense hadronic matter, which combines a multicomponent van der Waals (vdW)-type description with temperature-dependent effective degrees of freedom. Although the vdW formalism successfully reproduces interactions at finite density, in its standard form it cannot describe lattice-QCD thermodynamics, since it uses a fixed degeneracy. It is shown that a consistent description of the equation of state requires a temperature-dependent degeneracy $g(T)$ and an effective chemical potential $\mu (T)$. Within this approach, the trace anomaly (the trace of the energy-momentum tensor), i.e. the measure of nonconformality of the energy-momentum tensor normalized to $T^4$, is naturally reproduced together with its peak structure near the crossover region. The effective chemical-potential sector becomes particularly important in baryon-rich matter, whereas for the mesonic sector a separate dynamical description of the degrees of freedom is required.

    hep-phnucl-th0 citations
12. 12*

    Probing the small-scale primordial power spectrum via relic neutrinos and acoustic reheating

    Giovanni Piccoli🇨🇭 · Sunny Vagnozzi🇮🇹 · Joseph Silk🇫🇷

    We show that the dissipation of small-scale perturbations through diffusion damping after neutrino decoupling lowers the present-day neutrino temperature compared to the expected value of $1.96\text{K}$. This reduces the relic neutrino abundance by an amount controlled by the integral of the primordial curvature power spectrum ${\Delta }_{\mathcal{R}}^2(k)$. We find that a relic neutrino detection by PTOLEMY can set limits ${\Delta }_{\mathcal{R}}^2(k)\lesssim \mathcal{O}(0.1)$ on scales $k\lesssim 3\times 10^5{\text{Mpc}}^{-1}$, complementary to limits from Big Bang Nucleosynthesis, spectral distortions, pulsar timing arrays, and future dark ages 21-cm observations.

    hep-phastro-ph.COgr-qchep-th2 citations
13. 13*

    Quantumness of top quark pairs produced at LHC within SMEFT framework

    Amir Subba🇨🇳 · Yu Shi🇨🇳

    Top and anti-top quark pair production at LHC provides a unique setting to probe non-classical correlations at the TeV scale. We study quantum information (QI) properties of the $t\bar{t}$ spin state in $pp$ collisions at $\sqrt{s}=13$ TeV within the Standard Model Effective Field Theory (SMEFT), focusing on dimension-6 operators that induce anomalous chromo- and weak dipole moments of the top quark within their current experimental bounds. The $t\bar{t}$ spin density matrix is reconstructed from the joint angular distribution of the final state charged leptons in the $k$-$r$-$n$ helicity basis. We analyze three complementary QI quantities: concurrence-based quantum entanglement (QE), geometric quantum discord (GQD), and the Bell parameter,across four $t\bar{t}$ invariant-mass bins. Within the Standard Model (SM), non-vanishing QE appears only near threshold ($m_{t\bar{t}}\lesssim 400$ GeV), while GQD remains nonzero across the full phase space, indicating persistent non-classical correlations even for separable states. Anomalous chromo-dipole interactions modify these observables primarily near threshold: ${\hat{\mu }}_t$ induces asymmetric shifts, whereas ${\hat{d}}_t$ produces a mild symmetric response without Bell inequality violation. Among weak dipole operators, the CP-even coupling $C_2^V$ generates the largest deformation of the QI observables, while $\Delta C_1^{A,V}$ leave them unchanged. These results demonstrate that QI observables derived from the $t\bar{t}$ spin density matrix provide a complementary probe of anomalous top-quark interactions with distinct sensitivity to CP-even and CP-odd operator structures.

    hep-ph4 citations
14. 14*

    Explicit Conditions for Diagnosing Tree-Level Unitarity

    Jaehoon Jeong🇰🇷 · Pyungwon Ko🇰🇷 · Yu-Hui Zheng🇰🇷

    We explicitly present all coupling conditions required for tree-level unitarity (tree unitarity) in theories with a finite number of massive and massless particles of spin up to 1. They allow us to diagnose tree unitarity of a system using only its particle content in the mass basis, without reconstructing the full Lagrangian. We show that all four-point amplitudes whose high-energy growth is canceled by tree unitarity conditions are on-shell constructible, thereby motivating the recursive construction of four-point amplitudes. By examining their high-energy growth, we derive tree unitarity conditions for four-point amplitudes. Imposing these conditions to simplify the Lagrangian structure, we use the Stückelberg formulation to derive the tree unitarity conditions arising from all higher-point amplitudes. We show that all tree unitarity conditions are fully captured up to five-point amplitudes, ensuring no necessity of examining higher-point ones. We apply our results to systematically examine tree unitarity conditions in the dark sector with a massive dark photon and dark matter particles of spin up to 1, and extract the essential features for mass generation in the massive dark photon case. In addition, we show that our results allow us to conclude that theories without scalars require an infinite tower of vectors and fermions for tree unitarity. Finally unitarity and related issues in the Higgs portal VDM are discussed in brief.

    hep-phhep-th1 citation
15. 15*

    A Phenomenological Study of Semileptonic $B^{+}$ and $B_s^0$ Decays into Axial-Vector Mesons $(D_1(2420),D_1^{\prime }(2430),D_{s1}(2460),\text{and }{D}_{s1}^{\prime }(2536))$ within the Standard Model

    Rana Khan🇵🇰 · Qazi Maaz Us Salam🇵🇰 · Zohaib Aarfi🇵🇰 · Ishtiaq Ahmed🇵🇰

    We study semileptonic $B$ meson decays $B^{+}\to D_1^{(\prime )}{\ell }^{+}{\nu }_{\ell }$ and $B_s^0\to D_{s1}^{-(\prime )}{\ell }^{+}{\nu }_{\ell }$, where $\ell =\mu ,\tau$. The final state axial vector mesons are treated as mixtures of the heavy quark basis states with light degree of freedom angular momenta $j_{\ell }=1/2$ and $j_{\ell }=3/2$, parametrized by the mixing angle ${\theta }_{D_1}$. Using form factors obtained in the covariant light front quark model, we analyze the dependence of various observables on ${\theta }_{D_1}$ such as polarized and unpolarized branching ratios, the lepton forward-backward asymmetry, the longitudinal polarization fraction, and the lepton flavor universality ratios. In addition, we also discuss correlations among different observables. We study these observables in the experimentally motivated mixing angle regions as well as over a wider range of ${\theta }_{D_1}$. Our results show that branching ratios and other observables are sensitive to the axial-vector mixing structure. These predictions provide useful Standard Model benchmarks for future measurements of semileptonic $B_{(s)}$ decays into orbitally excited mesons and may help to clarify the long standing $1/2$ vs. $3/2$ puzzle through semileptonic $B$ decays.

    hep-ph0 citations
16. 16*

    Photoproduction of $J/\Psi$ in peripheral Oxygen-Oxygen collisions

    Pedro E. A. da Costa🇧🇷 · André V. Giannini🇧🇷 · Victor P. Gonçalves🇧🇷 · Bruno D. Moreira🇧🇷

    The photoproduction of $J/\Psi$ in peripheral Oxygen - Oxygen ($OO$) collisions at the Large Hadron Collider (LHC) is investigated considering distinct assumptions for the modeling of the nuclear photon flux, overlap function and dipole - proton scattering amplitude. Predictions for the associated rapidity distributions and total cross - sections are presented. Our results indicate that the experimental study of the photoproduction of $J/\Psi$ in peripheral $OO$ collisions is, in principle, feasible. In addition, they point out that the combination of the results for this final state in $OO$ collisions with those obtained for $PbPb$ collisions will allow us to derive important constraints on the description of photon - induced process at peripheral collisions.

    hep-phhep-exnucl-exnucl-th0 citations
17. 17*

    Comparison of the hadronic vacuum polarization between hadronic $\tau$-decay data and lattice QCD

    Noah Allen🇺🇸 · Diogo Boito🇧🇷 · Maarten Golterman🇺🇸 · Kim Maltman🇦🇺 · Lucas M. Mansur🇩🇪 · Santiago Peris🇪🇸

    We compare the isospin-one, vector-current hadronic vacuum polarization (HVP) obtained from isospin-symmetric lattice QCD with that obtained from a dispersive representation employing inclusive hadronic $\tau$ decay data corrected for isospin breaking. We consider the subtracted HVP evaluated at squared Euclidean momenta ranging from $0.5$ GeV${}^2$ to $12$ GeV${}^2$, together with the light-quark-connected HVP contribution to the muon anomalous magnetic moment and the short-, intermediate- and long-distance RBC/UKQCD window components thereof. Dispersive contributions from the region of hadronic invariant masses above the $\tau$ mass are evaluated using perturbative QCD. We also consider dispersive determinations using $\tau$ data only for contributions from two-pion, or two-pion and four-pion, modes, and evaluating the remaining contributions using exclusive-mode $e^{+}{e}^{-}\to \text{mbox}hadrons$ cross sections up to about 2 GeV, lessening the dependence on perturbation theory. We find generally good agreement between lattice and $\tau$-based results. However, a comparison of $\tau$-based window-quantity contributions for the two four-pion modes to expectations for those contributions based on the Pais relations and $e^{+}{e}^{-}$ four-pion cross sections, reveals significant differences for the $2{\pi }^{-}{\pi }^{+}{\pi }^0$ mode.

    hep-phhep-latPRD(2026)·2 citations
18. 18*

    Open LHC Monte Carlo Event Generation

    Enrico Bothmann🇨🇭 · Jon Butterworth🇬🇧 · Shu Chen🇬🇧 · Eda Erdogan🇨🇭 · Giovanni Guerrieri🇨🇭 · Christian Gütschow🇬🇧 · Martin Habedank🇬🇧 · Julie M. Hogan🇺🇸 · Venus Keus🇮🇪 · Sabine Kraml🇫🇷 · Van Dung Le🇫🇮 · Kati Lassila-Perini🇫🇮 and 7 other authors

    The LHC physics programme involves a vast amount of Monte Carlo event simulation. This paper reviews current efforts towards sharing the generated events as Open Data. Open Event Generation helps reduce duplication of effort and resource consumption, and benefits the whole High Energy Physics community. We give examples of use cases and user experiences, discuss financial and environmental savings, and suggest future directions.

    hep-phhep-ex1 citation
19. 19*

    Toward Charge-Dependent Tests of the Equivalence Principle: A Phenomenological Parameter and an Unexplored Frontier

    Renato Vieira dos Santos🇧🇷

    We introduce and define the phenomenological parameter $\kappa$, defined by $\Delta a/g=\kappa \Delta (q/m)$, to quantify potential linear coupling between electric charge and gravitational acceleration. A synthesis of existing precision equivalence principle experiments yields the first quantitative estimate of the effective sensitivity to this coupling: $|\kappa |<2.1\times 10^{-4}$ kg/C at 95\% confidence level. This constraint is approximately eleven orders of magnitude less stringent than corresponding bounds on composition-dependent violations, revealing that the electromagnetic axis remains a largely underexplored frontier in empirical gravity. We connect $\kappa$ to established frameworks -- the Standard-Model Extension and the $THϵ\mu$ formalism -- showing that it occupies a region of parameter space untouched by existing high-precision tests. An effective field theory analysis shows that dimension-six operators that couple curvature directly to the electromagnetic field strength are suppressed by the minuscule terrestrial spacetime curvature ($G_N{\rho }_{\oplus }\sim 10^{-55}{\text{GeV}}^2$) and are therefore phenomenologically irrelevant. Consequently, a future measurement of $\kappa$ at an accessible level would not probe minimal geometric couplings but would signal physics beyond minimal gravitational EFT, such as mediation by light scalar fields as in Einstein-Maxwell-Dilaton theory. We examine the Schiff-Barnhill effect, the primary systematic background for any such measurement, and show how it can be separated from a genuine signal. We outline the necessary experimental strategy, focused on maximizing charge-to-mass ratio differences, to transform this overlooked axis into a targeted probe for new physics.

    hep-phcond-mat.stat-mechgr-qcPRD(2026)·0 citations
20. 20*

    A New Look at the X Compositeness from its Lineshape

    A. Carducci🇮🇹 · G. Cianti🇮🇹 · P. D'Annibali · D. Germani🇮🇹 · A.D. Polosa🇮🇹

    The existing analyses on the X(3872) lineshape are consistent with the hypothesis that it is a compact particle composed of four quarks. This conclusion follows from fitting available data with a Flatte' distribution derived from an effective Lagrangian in which X, D, and D* are all elementary fields. A molecular X, i.e., a deuteron-like bound state of D and Dbar*, must instead be described by an effective theory where the X field is initially absent or introduced as an auxiliary, unphysical, field, yielding a lineshape parametrization that differs significantly from the Flatte' one. We demonstrate, in the analogous theory of nucleons with an auxiliary deuteron field, that this parametrization gives a fully consistent description of np--> deuteron --> np scattering data, and motivate applying the same method to the X lineshape.

    hep-ph1 citation
21. 21*

    Quasi Parton Distribution Functions in Covariant Quark Models

    Fatma Aslan🇺🇸 · Asli Tandogan🇺🇸 · Peter Schweitzer🇺🇸

    Quasi parton distribution functions (QPDFs) are defined in terms of QCD fields at spacelike separations evaluated in matrix elements of hadrons moving with velocity $v$. These objects can be studied in lattice QCD. In the limit when $v$ approaches the speed of light, QPDFs converge to PDFs. It is insightful to study QPDFs and their convergence in models. In this work, we first study the QPDFs in a broad class of quark models characterized by one common feature, namely the absence of gauge degrees of freedom. We provide general proofs for the convergence and sum rules of the unpolarized quark and antiquark QPDFs for both choices ${\gamma }^0$ and ${\gamma }^3$. We choose the Covariant Parton Model (CPM) as an illustration. We derive analytical results for the small-$x_v$ behavior of QPDFs and the energy-momentum tensor form factor ${\bar{c}}^q(t)$ at zero momentum transfer. These results are of interest as they correspond to a Wandzura-Wilczek-type approximation.

    hep-ph0 citations
22. 22*

    Tunneling and tidal stripping in multifield ultralight dark matter halos

    Benjamin V. Lehmann🇺🇸 · Jackie Lodman🇺🇸 · Thomas Steingasser🇪🇸

    Tidal stripping is a key feature of the evolution of dark matter (DM) halos, and has major implications for the population of low-mass galaxies. In the case of ultralight DM, tidal stripping proceeds not only classically, at the tidal radius, but also via a process analogous to quantum tunneling by long-wavelength particles out of the potential of a subhalo. This modified tidal stripping behavior leads to tight constraints on the particle mass as a function of subhalo and host properties. As many models of ultralight DM predict several independent species, it is crucial to understand how these constraints can be generalized to multifield halos with different particle masses. However, numerical challenges make it difficult to directly study the tunneling process in all but the simplest multifield scenarios. We introduce a simplified approach based on semiclassical methods that entirely sidesteps the most difficult aspects of the numerical problem, and we apply this to the study of tunneling in multifield halos. Our results significantly clarify the physics of tidal stripping for ultralight DM halos even in the single-field case: we provide first-principles derivations of features of the tunneling rate previously suggested by empirical fits. We then evaluate stability bounds on two-field halos for the first time, for a wide range of density and particle mass ratios. We show that for particular parameter combinations, the stability bounds in the two-field case can be somewhat relaxed relative to the single-field case, but for much of the parameter space, the constraints become more stringent. We discuss the path towards probing realistic multifield ultralight DM halos.

    hep-phastro-ph.COastro-ph.GA1 citation
23. 23*

    Neutral-current neutrino-nucleus scattering off I (127) and Cs (133): Coherent and incoherent contributions with electroweak refinements for odd-A nuclei

    Muhammad Farooq🇵🇰 · Shakeel Mahmood🇵🇰 · Muhammad Faisal Khan

    Calculations of neutral-current neutrino-nucleus scattering cross sections are important for interpreting low- and intermediate-energy neutrino data, where terrestrial measurements remain limited. The first observation of coherent elastic neutrino-nucleus scattering (CEvNS) in 2017 with a CsI[Na] detector at the Spallation Neutron Source reported results consistent with Standard Model expectations, motivating improved theoretical descriptions beyond the purely coherent regime. In this work, we calculate neutral-current scattering cross sections for 127I and 133Cs within a unified analytical framework that consistently incorporates coherent elastic, incoherent excitation, and spin-dependent axial contributions relevant for odd-A nuclei. A consistent distinction between nuclear and nucleon form factors is maintained throughout the formalism. The incoherent contribution is evaluated using structure-function methods, providing a physically motivated decomposition of the total cross section. Electroweak effects are included through momentum-transfer-dependent sin^2(theta_W) corrections in the MS-bar scheme together with flavor-dependent neutrino charge-radius contributions implemented consistently in the vector couplings. Cross sections are presented as functions of neutrino energy and for decay-at-rest neutrino spectra in the low-to-intermediate energy region where elastic and quasi-elastic processes dominate. Inclusion of incoherent and axial contributions enhances the total cross section near Enu ~ 10 MeV, while the incoherent component becomes dominant around Enu ~ 50 MeV. Expected interaction rates for decay-at-rest neutrinos are of order 0.1 events kg^-1 yr^-1 near a 40 keV recoil threshold. The results provide a systematic assessment of subleading contributions relevant for CsI-based detectors and astrophysical neutrino applications.

    hep-phEur.Phys.J.Plus(2026)·0 citations
24. 24*

    End-to-End Population Inference from Gravitational-Wave Strain using Transformers

    Konstantin Leyde🇺🇸 · Stephen R. Green🇬🇧 · Maximilian Dax🇩🇪 · Matthew Mould🇬🇧 · Cecilia Maria Fabbri🇬🇧 · Jonathan Gair🇩🇪

    The population of compact binaries encodes information about their astrophysical origins and the expansion of the universe. Hierarchical Bayesian methods infer these properties by combining single-event posteriors. As catalogs grow, however, this approach becomes computationally expensive and is subject to increasing Monte Carlo uncertainty. We introduce Dingo-Pop, a simulation-based framework that infers population posteriors directly from gravitational-wave strain data. The data for each event are embedded into low-dimensional tokens and combined using a transformer trained on simulated catalogs subject to selection effects. This enables (i) population inference without per-event Monte Carlo sampling noise, (ii) amortization across variable catalog sizes using a single network, and (iii) end-to-end inference in about one second. We train a network for catalog sizes of 25 to 1000 events, and obtain well-calibrated posteriors consistent with traditional methods. By avoiding per-event analyses that can take hours to days, Dingo-Pop enables new classes of large-scale injection studies; as an application, we examine how spectral-siren Hubble constant uncertainties change with catalog size.

    ↳ gr-qcastro-ph.COhep-ph7 citations
25. 25*

    MeVPrtl: An Event Generator for Dark Sector Particles in the Short-Baseline Neutrino Program

    ICARUS Collaboration · SBND Collaboration (for the SBN Program)

    MeVPrtl is a modular event generator of beyond the Standard Model (BSM) physics particles developed for use in the Short-Baseline Neutrino (SBN) Program. A large class of BSM physics models predict that new particles could be produced in the intense Booster Neutrino Beam (BNB) and Neutrinos at the Main Injector (NuMI) beams at Fermilab, travel to the SBN Program detectors, and decay into Standard Model (SM) particles. These new physics models are motivated by dark matter, the neutrino mass scale, and a solution to the strong CP problem. MeVPrtl provides an interface to implement the overlapping phenomenology of these models, and to connect them with meson flux inputs and object outputs used by the SBN Program's LArSoft-based detector simulation. Implementations for the Higgs portal, heavy neutral lepton, and heavy QCD axion models exist within MeVPrtl. In this paper these implementations and their validation, as well as details of the MeVPrtl interface, are specified.

    ↳ hep-exhep-ph0 citations
26. 26*

    CaloArt: Large-Patch x-Prediction Diffusion Transformers for High-Granularity Calorimeter Shower Generation

    Zhengkun Huang · Gongxing Sun🇨🇳

    High-granularity calorimeters make ML-based fast shower simulation a high-dimensional generative modeling problem, where voxel-space generators must balance physics fidelity with training and inference cost. This work studies large-patch tokenization with x-prediction, enabling efficient raw voxel generation. We propose CaloArt, a modernized DiT-style backbone with 3D positional encoding and architectural refinements, trained via conditional flow matching with decoupled prediction and loss spaces. On CaloChallenge Dataset 2, where small patch size remains affordable, v-prediction performs well, and CaloArt achieves the best FPD, strongest high-level metrics, and strongest ResNet classifier metrics. On CaloChallenge Dataset 3, the 40500-voxel grid makes large patches necessary; x-prediction improves all reported metrics over v-prediction and places CaloArt on the quality-generation-time Pareto frontier. The final CCD2 and CCD3 models both retain O(10) ms single-GPU generation time, with 9.71 and 11.14 ms per shower. These results support large-patch voxel-space diffusion transformers with x-prediction as a compute-efficient route to high-granularity calorimeter shower synthesis, reducing training and inference cost without a pretrained latent tokenizer.

    ↳ physics.ins-dethep-exhep-ph1 citation
27. 27*

    Mass radius and D-term of atomic nuclei in relativistic mean field theory

    Yoshitaka Hatta🇺🇸 · Tomohiro Oishi🇯🇵 · Makoto Oka🇯🇵

    Based on relativistic mean field theory for atomic nuclei, we compute the mass radius and other radii associated with the energy momentum tensor for dozens of spin-0 nuclei across the nuclear chart. We also compute the D-term of these nuclei, the forward limit of the gravitational form factor $D(t=0)=D$. The dependence on the neutron number $N$ is systematically studied for calcium (Ca), nickel (Ni), zirconium (Zr), tin (Sn) and lead (Pb) isotopes. Remarkably, $|D|$ does not monotonically increase with $N$. Instead, it exhibits local maxima and minima when $N$ equals a magic number and even a sub-magic number. This results in characteristic kinks in the mass, scalar, tensor and shear radii of these isotopes. Our work for the first time elucidates the strong sensitivity of the various mechanical properties of nuclei to the nuclear shell structure.

    ↳ nucl-thhep-phPRC(2026)·1 citation
28. 28*

    Tracking down the broadband polarimetric properties of PG 1553+113

    Riccardo Middei · Svetlana G. Jorstad · Alan P. Marscher · Ioannis Liodakis🇫🇮 · Matteo Perri · Alessandro Maselli · Stefano Ciprini🇮🇹 · Emanuele Nardini · Simonetta Puccetti · Laura Di Gesu🇺🇸 · Iván Agudo · Dawoon E. Kim and 69 other authors

    We report on a nine-month monitoring campaign of the blazar PG 1553+113, relying on three observations carried out in 2025 with the Imaging X-ray Polarimetry Explorer (IXPE) and supported by multi-wavelength facilities. The source displayed pronounced variability across the electromagnetic spectrum, with X-ray flux changes by up to a factor of $\sim 5$ and complex evolution of the optical polarization properties, including one of the largest (exceeding $150^{\circ }$) and fastest rotations in the electric vector position angle (EVPA) ever recorded. This swing of the EVPA was also accompanied by a temporary drop of the optical polarization degree to nearly zero. Significant X-ray polarization was observed during the third IXPE pointing, with a polarization degree ${\Pi }_{\mathrm{X}}=(18.4\pm 5.8)\%$ and ${\Psi }_{\mathrm{X}}=74^{\circ }\pm 9^{\circ }$ in the 2--8~keV band, while only upper limits were obtained in the first two epochs. The optical data show that the second IXPE observation occurred shortly after a dramatic optical polarization event characterized by a rapid EVPA swing and strong depolarization. Two possible scenarios may explain the broadband polarimetric behavior: (i) the superposition of two emitting regions with nearly orthogonal magnetic field configurations and variable relative contributions, and (ii) the interaction of a single emitting region with a shock that temporarily reorders the magnetic field. In both cases, the data support a picture in which the X-ray and optical emissions arise from closely related but not strictly co-spatial regions within a dynamically evolving, magnetically structured jet.

    ↳ astro-ph.HEhep-phApJ(2026)·0 citations

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