Thu·Mar 26, 2026Thursday·March 26, 2026

1. 01*

   Semi-inclusive deep-inelastic scattering on a polarized spin-1 target. I. Cross section and spin observables

   W. Cosyn🇺🇸 · C. Weiss🇺🇸

   We develop the theoretical framework for semi-inclusive deep-inelastic scattering on a polarized spin-1 target and apply it to scattering on the polarized deuteron with spectator nucleon tagging. In Part I (this article) we present the general form of the semi-inclusive cross section and polarization observables for the spin-1 target. A relativistically covariant formulation in terms of 4-vectors and invariant polarization parameters is employed. The target polarization is described by a spin density matrix with vector and tensor polarization. The spin and azimuthal angle dependence of the semi-inclusive cross section is derived and parametrized in terms of invariant structure functions. To validate the result, the structure functions are expressed as photon-target helicity amplitudes with known symmetry properties. The expressions presented here are kinematic (no assumptions about particle production dynamics) and valid in all regions of the deep-inelastic final state (current and target fragmentation regions). In Part II (following article), we consider deep-inelastic scattering on the polarized deuteron with spectator nucleon tagging as a special case of target fragmentation. The semi-inclusive structure functions are computed by separating nuclear and hadronic structure, and the polarization observables are explored as functions of the tagged nucleon momentum.

   hep-phnucl-exnucl-thPRC(2026)·2 citations
2. 02*

   Semi-inclusive deep-inelastic scattering on a polarized spin-1 target. II. Deuteron and spectator nucleon tagging

   W. Cosyn🇺🇸 · C. Weiss🇺🇸

   We develop the theoretical framework for semi-inclusive deep-inelastic scattering on a polarized spin-1 target and apply it to scattering on the polarized deuteron with spectator nucleon tagging. In Part I (previous article) we present the general form of the semi-inclusive cross section and polarization observables for the spin-1 target. In Part II (this article) we consider deep-inelastic scattering on the polarized deuteron with spectator nucleon tagging as a special case of target fragmentation. Methods of light-front quantization are employed to separate nuclear and hadronic structure in the high-energy process and achieve a composite description. The light-front wave function of the polarized deuteron is obtained from a rotationally covariant 3-dimensional wave function in the center-of-mass frame of the proton-neutron system. The tagged structure functions are computed in the impulse approximation. The momentum and spin distribution of the active nucleon are controlled by the deuteron polarization and the detected spectator momentum ($D/S$ wave ratio). The cross section and spin asymmetries are evaluated for general deuteron polarization (vector and tensor, longitudinal and transverse) as functions of the spectator momentum. Tensor-polarized spin asymmetries of order unity are achieved for spectator momenta $\sim$ 300 MeV, which select configurations with large $D$-wave. Sum rules for the tagged spin structure functions are derived. The results can be used for simulations of spectator tagging in future polarized fixed-target experiments (Jefferson Lab) or at the Electron-Ion Collider.

   hep-phnucl-exnucl-thPRC(2026)·2 citations
3. 03*

   Meson mixing effects on the speed of sound in isospin-imbalanced matter

   Alejandro Ayala🇲🇽 · Bruno S. Lopes🇧🇷 · Ricardo L. S. Farias🇧🇷 · Luis C. Parra🇲🇽

   We explore isospin imbalanced strongly interacting matter within the two-flavor Linear Sigma Model with quarks, an effective model for low-energy QCD. At one loop order, including quark, pion, and sigma fluctuations while respecting chiral symmetry, we find that the formation of an isospin condensate necessarily gives rise to a Goldstone mode. This mode enforces a nontrivial relation between the chiral and isospin condensates through the mixing of charged pions and the sigma field in the condensed phase. From the resulting thermodynamic potential, we compute the speed of sound and observe a pronounced peak as a function of the isospin chemical potential. Although the peak of the speed of sound may be described at tree-level and including only quarks in the analysis, meson dynamics introduces further constraints that influence the position and width of the peak which making it to align well with lattice QCD simulations. Therefore we identify that the shape and position of the peak is a consequence of the Goldstone mode dynamics and of the associated charged pion sigma mixing.

   hep-phhep-lathep-thnucl-thPoS(2026)·0 citations
4. 04*

   Regge spectral generator and form factors from hard exclusive amplitudes in holographic QCD

   Guy F. de Teramond🇨🇷 · Stanley J. Brodsky🇺🇸 · Hans Gunter Dosch🇩🇪

   We show that the infinite tower of hard exclusive amplitudes in holographic light-front QCD leads to a spectral generator $G(\alpha ,\lambda )$ which encodes the full Regge spectrum. The construction assumes a Poisson distribution of Fock-state components, where $\lambda$ represents the average parton multiplicity above the valence configuration. The resulting generator yields a Regge spectrum invariant under continuous $\lambda$-deformations. Its even- and odd-twist projections yield the meson and baryon form factors with a single value of $\lambda$, fixed by the pion charge radius, which in turn determines the full $Q^2$ dependence. The constituent counting rules for both sectors follow from the structure of the spectral generator, which also provides a compact analytic representation of parton distributions.

   hep-phPRL(2026)·0 citations
5. 05*

   CP violations in neutrino oscillations modulated by singular and non-singular gravities

   Ze-Wen Li🇨🇳 · Shu-Jun Rong🇨🇳 · Ya-Ru Wang🇨🇳

   Flavor oscillations in curved space-time provide a novel channel to explore the unknown parameters of neutrinos. In this work, the gravity-modulated CP violations (CPVs) in neutrino oscillations were investigated under the Reissner-Nordstrom, Hayward, and Simpson-Visser metric. The interplay among the CPV, the properties of neutrinos, and the space-time is illustrated with analytical and numerical methods. The morphologies of the flavor-oscillation curves show that the information on the mass-ordering, the absolute mass, and the gravitational parameters could be encoded into the amplitudes and periods of the CPVs. Hence, the characteristic of the space-time background may be identified through its modulation effects on the CPV, such as amplification, damping on the amplitudes.

   hep-phgr-qc0 citations
6. 06*

   Impact of muons on the bulk viscosity of neutron star matter metamodels

   José Luis Hernández🇪🇸 · Cristina Manuel🇪🇸 · Laura Tolos🇪🇸

   Recent studies invoke a unified description of different neutron star observables using metamodels, which parametrize the Equation of State (EoS) of neutron star matter close to nuclear saturation density in terms of few nuclear parameters. In this light, the bulk viscosity in the neutrino-transparent regime of dense nuclear matter composed of neutrons, protons and electrons has been recently shown to be mostly sensitive to the value of the nuclear symmetry energy. As muons are also present at densities around nuclear saturation, we further analyse in this manuscript their impact on this transport coefficient as a function of the slope $L$ of the symmetry energy. We find that muons introduce both relevant qualitative and quantitative effects in the bulk viscous dissipation. Increasing $L$ by a factor two has an effect of several orders of magnitude on the (frequency-independent) bulk viscosity. We also find that for all values of $L$ the frequency-dependent bulk viscosity presents a double peak structure for some values of the density, absent without muons. This also represents changes in orders of magnitude of the viscosity in narrow windows of densities that could be attainable in a neutron star for enough high values of $L$. We present a systematic numerical analysis of both second-order transport coefficients, frequency-dependent bulk viscosity, and damping times of density oscillations as a function of the density and the slope, and find when these could be relevant for the dynamics of the merger of neutrons stars.

   hep-phastro-ph.HEnucl-th1 citation
7. 07*

   Gravitational mass generation and consistent non-minimal couplings: cubics and quartics of a massive vector

   Carlo Marzo🇪🇪

   An attempt to evade the strict uniqueness of consistent interactions involving spin-2 particles is made by modifying the Noether procedure from the outset. A vector field is introduced, coupled to a graviton already at the level of quadratic mixing. The byproduct is a gauge-invariant mass for the vector and novel consistent interactions, here derived and tested up to quartic order. A simple geometric interpretation of the vector field appears possible.

   hep-phhep-th0 citations
8. 08*

   Spin polarization and quantum entanglement of baryon-antibaryon pairs produced in electron-positron annihilation

   Cheng Chen🇨🇳 · Ju-Jun Xie🇨🇳

   In this work, we systematically investigate the evolution of spin polarization and quantum entanglement in cascade decays of baryon-antibaryon pairs, which are produced in electron-positron annihilation. We derive a fully analytical spin density matrix explicitly expressed in terms of spin polarization observables, extend this formalism to multi-step cascade decay scenarios, and establish compact recursive relations to facilitate density matrix calculations for such processes. It is found that when maximal parity violation occurs during a decay, the resulting final-state particles are fully polarized and exist in a non-entangled state. Furthermore, we demonstrate that quantum entanglement amplification is a generic characteristic of charge-conjugate decays under $CP$ conservation when the initially produced baryon-antibaryon pair is polarized.

   hep-ph2 citations
9. 09*

   Sensitivity of the RECODE Reactor CEvNS Experiment to the Dark Axion Portal

   Yingji Shen🇨🇳 · Jie Tang🇨🇳 · Li Wang🇨🇳 · Yongcheng Wu🇨🇳 · Litao Yang🇨🇳

   Reactor CEvNS experiments provide a powerful probe of the physics beyond the Standard Model (BSM) with the intense flux of neutrinos, photons, and other particles produced in nuclear reactors. In this work, we investigate the sensitivity of reactor CEvNS experiments to the dark axion portal, which connects the axion or axion-like particle to the dark photon. We focus in particular on the RECODE experiment, while also considering other reactor-based experiments such as CONUS and MINER. We find that reactor CEvNS experiments offer enhanced sensitivity in the sub-MeV region compared with the existing constraints from B factories, and can probe the portal coupling down to $\mathcal{O}(10^{-3})$ for $G_{a\gamma {\gamma }^{\prime }}$.

   hep-ph4 citations
10. 10*

    Two-component dark matter from a flavor-dependent $U(1)$ gauge extension

    N. T. Duy🇻🇳 · Duy H. Nguyen · Do Thi Ha · Duong Van Loi🇻🇳

    We revisit the dark matter phenomenology of a flavor-dependent $U(1{)}_X$ gauge extension of the Standard Model, where anomaly cancellation predicts the existence of exactly three fermion generations and requires the presence of three right-handed neutrinos. In Ref.~\cite{VanLoi:2023utt}, a strong hierarchy between the vacuum expectation values of two singlet scalars, ${\text{La}}_2\gg {\text{La}}_1$, renders all ${\mathbb{Z}}_2$-odd scalar states heavy, resulting in a two-component dark matter scenario composed exclusively of fermions. In the present work, we relax this simplifying assumption and consider a more general mass spectrum. In particular, scalar mixing can naturally lead to a situation in which the lightest ${\mathbb{Z}}_2$-odd particle is a scalar rather than a fermion. As a consequence, the model admits a qualitatively new realization of two-component dark matter consisting of one fermionic and one scalar component, in addition to the purely fermionic scenario studied previously. We perform a dedicated phenomenological analysis of these two-component dark matter realizations, focusing on the coupled thermal freeze-out dynamics and the resulting relic abundance. Constraints from the observed relic density and current direct-detection limits are taken into account, and viable regions of parameter space are identified.

    hep-phhep-th0 citations
11. 11*

    LHC Run-3, Dark Matter and Supersymmetric Spectra in the Supersymmetric Pati-Salam Model

    Ali Muhammad🇨🇳 · Imtiaz Khan🇨🇳 · Tianjun Li🇨🇳 · Shabbar Raza🇵🇰 · Mussawir Khan🇨🇳 · Pirzada🇨🇳

    Driven by the growing agreement between the experimentally measured muon anomalous magnetic moment and its SM prediction, we reexamine phenomenological consequences of the MSSM, which is embedded in the supersymmetric $SU(4{)}_C\times SU(2{)}_L\times SU(2{)}_R$ Pati-Salam model. In contrast to earlier studies that predominantly favored a specific sign for the Higgsino mass parameter, our analysis systematically explores both $\mu >0$, and $\mu <0$ scenarios in light of current collider, cosmological, and DM constraints. Within this framework, we identify viable parameter space regions where the observed DM relic density is reproduced through multiple mechanisms: co-annihilations involving sbottom-neutralino, gluino-neutralino, stop-neutralino, stau-neutralino, and chargino-neutralino coannihilation, as well as resonant s-annihilation channel via the pseudoscalar Higgs boson. We demonstrate that all such scenarios are consistent with present bounds from LHC supersymmetry searches, the Planck~2018 DM relic density bound, and current limits from DD DM searches. Our results reveal characteristic mass spectra associated with these mechanisms. In particular, sbottom-neutralino coannihilation typically requires sbottom masses near $2.8\text{TeV}$, while gluino-neutralino and stop-neutralino coannihilation scenarios allow gluino masses in the range $1$--$3\text{TeV}$ and stop masses between $1$ and $3.5\text{TeV}$. In coannihilation-dominated regions, the stau and chargino masses may reach values as high as $3.8\text{TeV}$, whereas viable $A$ resonance solutions are realized for pseudoscalar Higgs masses spanning approximately $1.6$--$3.8\text{TeV}$. We anticipate that a portion of the parameter space will be accessible to supersymmetry searches in LHC Run-3 and future runs.

    hep-phPLB(2026)·4 citations
12. 12*

    Magnetic-monopole resummation justifies perturbatively calculated collider production cross sections

    Jean Alexandre🇬🇧 · Nick E. Mavromatos🇬🇷 · Vasiliki A. Mitsou🇪🇸 · Emanuela Musumeci🇪🇸

    A one-loop resummation scheme, inspired by Dyson-Schwinger (DS) formalism of strongly coupled quantum field theories, is applied to spin-1/2 magnetic monopoles (MMs), in the context of an effective field theory (EFT), invariant under the gauge group U(1)_em x U(1)', where U(1)' is a dual strongly coupled Abelian interaction, associated with a "dark photon". The latter leads to a MM appearing as a limiting case of a "dyon", with a tiny "electric charge", compensated by a huge wave-function renormalization of the MM, thereby leading to a finite renormalized MM-photon coupling. An ultra-violet fixed point structure is found in the resummed theory, which is purely non-perturbative due to different boundary conditions of the resummation equations, compared to the weak coupling (perturbative) case. The renormalized coupling of the MM to the electromagnetic photon in the fixed-point theory is identified with the magnetic charge, compatible with the Dirac quantization condition. This provides for the first time a formal justification of the use of tree-level Drell-Yan and photon-fusion MM production processes in collider searches, and of the corresponding cross sections and MM mass bounds thereof. The latter provide a means to constrain the resummed-EFT parameters experimentally. The DS resummation applies here primarily to elementary MMs. However, this approach may also be applied to the last stage (collapse) of the formation of composite MM pairs at colliders, in case they behave as quantum excitations, with their core radius comparable to the Compton wavelength, thereby avoiding the extreme suppression of their production.

    hep-phhep-exhep-thEPJC(2026)·3 citations
13. 13*

    Why are the dilepton temperatures at the relativistic heavy-ion colliders are constant, T ~ 0.3 GeV?

    Horst Stoecker🇩🇪 · Leonid M. Satarov🇩🇪 · Volodymyr Vovchenko🇺🇸

    The STAR collaboration at RHIC and the ALICE collaboration at the LHC have reported dielectron spectra in the intermediate mass region, M = (1-3) GeV, which reveal a strikingly constant, energy-independent emission temperature $T_{IMR}\simeq 0.3\text{GeV}$ over a broad range of collision energies, $\sqrt{s_{NN}}=27-5020\text{GeV}$. This unexpected ''thermostat'' behavior raises fundamental questions: why does the temperature remain constant despite increasing collision energy,and what mechanism governs this apparent universality?

    hep-ph1 citation
14. 14*

    Chiral enhancement in the vector-like fourth family: Case of $b\to s\gamma$

    Junichiro Kawamura🇯🇵 · Yuji Omura🇯🇵

    We demonstrate that a vector-like fourth family of quarks induces a genuine chiral enhancement in $b\to s\gamma$, which is absent in the Standard Model (SM). The coexistence of doublet and singlet states allows the chirality flip to occur inside the loop, leading to contributions proportional to the heavy vector-like mass. The resulting amplitude is enhanced by a factor ${\overline{\lambda }}_d{v}_H/m_b$, which can be as large as $\mathcal{O}(40)$ for moderate Yukawa couplings. This leads to sizable deviation from the SM prediction even for $\mathcal{O}(\mathrm{TeV})$ vector-like quark masses and small mixing angles. We find that $\mathrm{Br}(\overline{B}\to X_s\gamma )$ provides the most stringent constraint on this scenario among a wide range of precision observables.

    hep-phhep-exJHEP(2026)·1 citation
15. 15*

    Dynamical generation of charmonium-like tetraquarks in an off-shell coupled-channel formalism

    Hee-Jin Kim🇰🇷 · Hyun-Chul Kim🇰🇷

    We investigate the dynamical generation of charmonium-like ($I=0$) with spin-parity $J^{PC}=0^{++},1^{++},2^{++}$, and $3^{--}$ in the mass range of $3.6$ to $4.3$ GeV. We employ the off-shell coupled-channel formalism, constructing kernel amplitudes from effective Lagrangians that respect heavy-quark spin-flavor and chiral symmetries. To focus solely on dynamically generated states, we explicitly exclude $s$-channel pole diagrams and include only $t$- and $u$-channel meson exchanges. Solving the integral equations, we identify six poles in the complex energy plane. In the scalar ($0^{++}$) sector, we find a bound state below the $D\bar{D}$ threshold and a resonance at $\sqrt{s_R}=(3861-i23)\mathrm{MeV}$. For the axial-vector ($1^{++}$) sector, the experimentally observed ${\chi }_{c1}(3872)$ is reproduced as a bound state near the $D{\bar{D}}^{\ast }$ threshold, alongside a broader resonance at $(3961-i32)\mathrm{MeV}$, which is a plausible candidate for the $X(3940)$. Furthermore, we find a narrow tensor ($2^{++}$) state at $4005\mathrm{MeV}$ and a vector ($3^{--}$) state at $4030\mathrm{MeV}$. The present results demonstrate that coupled-channel dynamics, particularly involving the $D^{\ast }{\bar{D}}^{\ast }$ channel, play a crucial role in the formation of these charmonium-like exotic states.

    hep-phhep-ex1 citation
16. 16*

    Dilaton Sum Rules of Gravitational Form Factors in QCD at Order ${\alpha }_s$

    Claudio Corianò🇮🇹 · Stefano Lionetti🇮🇹 · Dario Melle🇮🇹 · Leonardo Torcellini🇮🇹

    We formulate a partonic description of hadronic gravitational form factors within QCD, focusing on the three-point function of the energy-momentum tensor and two gluon currents. Despite the lack of exact conformal symmetry in QCD, the correlator may be organized around the conformal limit through momentum-space CFT methods, suitably adjusted for gauge-fixing effects. This yields a tensor decomposition into spin-2, spin-1, and spin-0 sectors, with the spin-0 contribution governed by the conformal anomaly. The corresponding anomaly form factor satisfies a mass-independent dispersive sum rule and allows a dilaton-like interpretation. In the light-cone limit, this term and an additional traceless structure become dominant, indicating an effective anomaly-mediated description relevant to hadronic gravitational form factors.

    hep-phhep-thPoS(2026)·1 citation
17. 17*

    Lyman-$\alpha$ Forest Constraint on Dark Matter from Dark Sector Decay

    Si-Yuan Zhao🇨🇳 · Yi-Cheng Dai🇨🇳 · Wei Liao🇨🇳 · Yi-Song Lu🇨🇳

    By exploiting small-scale structure formation probed by Lyman-$\alpha$ forest observations, we study constraints on a model of dark matter from dark sector decay. We compute the phase space distribution of the dark matter and the linear matter power spectrum. We map the non-thermal dark matter distribution in this dark matter model to an approximate thermal warm dark matter distribution, and use this approximation to obtain a constraint from the Lyman-$\alpha$ forest observation. We combine the latest Lyman-$\alpha$ forest bounds with the constraint from the Big Bang Nucleosynthesis. As these two probes offer highly complementary constraints, we impose strong limits on sub-GeV dark matter. Consequently, masses lighter than $\sim 10^{-1}$ GeV are excluded, thereby significantly limiting the allowed parameter space. More broadly, our findings demonstrate the utility of small-scale structure observations in testing non-thermal dark matter paradigms, offering valuable insights for exploring a wider class of late-time decay models.

    hep-phastro-ph.COJCAP(2026)·6 citations
18. 18*

    Effects of the initial-state geometry on D-meson production in pp and pPb collisions

    R. Terra🇧🇷 · A. V. Giannini🇵🇹 · F. S. Navarra🇧🇷

    Going from lower to higher multiplicity events in proton-proton and proton-lead collisions, the data show a stronger than linear growth of the D-meson normalized yields. In this contribution we try to understand this behavior using a Monte Carlo event generator which implements the $k_T$-factorization formalism. We use different spatial distribution of matter in the proton and in the lead nucleus at the initial stage of these collisions. We find that, with all the tested spatial distributions, the model reproduces well the behavior seen in the data. We conclude that this observable is not appropriate for a detailed study of the spatial distribution of matter in the proton.

    hep-phnucl-th0 citations
19. 19*

    Neutrino mass anarchy and leptogenesis

    Qi An🇨🇳 · Yan Shao🇨🇳 · Zhen-hua Zhao🇨🇳

    In this paper, we investigate leptogenesis under the neutrino mass anarchy hypothesis in both type-I and type-II seesaw models. We first revisit the corresponding study in the type-I seesaw framework with two improvements: in contrast to Ref.[25], where an approximate $U(1)$ flavor symmetry was imposed to ensure sizable hierarchies among the right-handed neutrino masses and Yukawa couplings, we adopt a fully general anarchy scenario with completely random and structureless neutrino mass and Yukawa matrices; moreover, given the crucial role of lepton flavors in both the generation and washout of the lepton asymmetry, flavor effects are consistently incorporated throughout our analysis. We then extend our investigation to the type-II seesaw framework, in which leptogenesis proceeds via the out-of-equilibrium decays of a scalar triplet.

    hep-ph0 citations
20. 20*

    Multi-component Dark Matter and leptogenesis with double seesaw in an extended left-right symmetric theory

    Ankita Kakoti🇮🇳

    Left-Right Symmetric theory has proved to be one of the most successful models in explaining the origin of neutrino mass and mixings, and the phenomenological origin of neutrinoless double beta decay, lepton flavor violation as well as leptogenesis within its regime. In the current work, left-right symmetric model has been extended with a sterile neutrino per generation, which acts as a dark matter candidate within the model. The model has been realized using $A_4$ modular symmetry and the primary focus of the work rests on investigating the impact of assigning different modular weights to the particle content of the model and hence study its effects on the results pertaining to relic abundance of dark matter and also leptogenesis within its framework.

    hep-ph0 citations
21. 21*

    Causal-Horizon Scaling of Quarkonium Suppression in Strong QCD Fields

    Yi Yang🇹🇼

    The simultaneous observation of strong sequential bottomonium suppression and small azimuthal anisotropy constrains the time scale and geometry of quarkonium dissociation in relativistic heavy-ion collisions. We investigate an early-time contribution in which strong pre-equilibrium color fields generate an effective proper-acceleration scale and an associated causal length. The maximal inverse causal-length scale is fixed through the phenomenological anchoring condition $T_{U,\mathrm{eff}}^{\max }\simeq T_c$, while the local kinematic acceleration notation $T_{U,\mathrm{loc}}$ is kept distinct from an equilibrium temperature. The survival probability is described by an event-averaged one-scale exponential ansatz. With no state-by-state adjustment, the resulting horizon component captures the main LHC state ordering and centrality trend. For the directly measured ${\rm Y}(2S)$ to-${\rm Y}(1S)$ double ratio, the anchored horizon coefficient and one effective late-stage coefficient give a quantitative conditional description. Because both contributions are assigned the same centrality function, the data constrain their combined exponent rather than a unique partition between early- and late-stage suppression. At RHIC, the absolute $R_{AA}$ central values lie below the isolated horizon component, while the relative $2S$-to-$1S$ suppression remains compatible with the predicted state-size hierarchy within present uncertainties. Because the proposed early factor is local and scalar, its contribution is identically $v_2^H=0$ within the idealized factorized construction, consistent with current CMS measurements.

    hep-phhep-exnucl-exnucl-thPRC(2026)·1 citation
22. 22*

    ACT-Planck data and phase transitions from a viable no-scale Standard Model completion

    Filippo Cutrona🇮🇹 · Francesco Rescigno🇮🇹 · Alberto Salvio🇮🇹

    Classically scale-invariant (and perturbative) theories provide a way to understand large hierarchies, as scales are generated through dimensional transmutation. They always lead to first-order phase transitions, since symmetries are radiatively broken, and they generically feature quasi-flat potentials, which are suitable for inflation. We construct a simple but fully realistic model of this kind that accounts for all observational evidence of new physics and is remarkably compatible with the most recent constraints on inflationary observables from both the Planck/BICEP/Keck and the Atacama Cosmology Telescope (ACT) collaborations. This model illustrates how classical scale invariance generically leads to a non-standard cosmology in which inflation occurs in two stages: a slow-roll stage and a thermal stage, separated by a radiation-dominated era.

    hep-phastro-ph.COgr-qchep-thPRD(2026)·1 citation
23. 23*

    Constraints on Light Sterile Neutrinos and Scalar Non-Standard Interactions Using the First Reactor Antineutrino Oscillation Results at JUNO

    L. J. Flores🇲🇽 · R. Pacheco-Aké🇲🇽 · Eduardo Peinado🇲🇽 · G. Sanchez Garcia🇲🇽 · E. Vázquez-Jáuregui🇲🇽

    Constraints on light sterile neutrinos and scalar non-standard neutrino interactions are obtained from the first reactor antineutrino results reported by JUNO. The analysis is based on a spectral ${\chi }^2$ fit to the prompt-energy distribution corresponding to 59.1 days of data, including full three-flavor oscillations extended to a $3+1$ framework and effective scalar NSI contributions. The reactor flux is modeled using the Daya Bay measured spectrum, and systematic uncertainties are accounted for through a set of nuisance parameters describing reactor flux normalization, spectral shape, background normalization, and detector response. It is found that JUNO is already sensitive to light sterile neutrinos in the mass-splitting range $10^{-5}\lesssim \Delta m_{41}^2/{\text{eV}}^2\lesssim 10^{-2}$, probing mixing amplitudes down to ${\sin }^{2}2{\theta }_{14}\sim \mathcal{O}(10^{-1})$. In addition, a constraint on the scalar NSI parameter $|{\eta }_{ee}|<\mathcal{O}(10^{-2})$ is obtained, with correlations with solar oscillation parameters. These results demonstrate the potential of JUNO to probe small deviations from the Standard Model resulting from new physics through precision measurements, with significant improvements expected as statistics and systematic control improve.

    hep-phPRD(2026)·3 citations
24. 24*

    A velocity-dependent two-scale model for cosmic string networks with small-scale structure

    Teresa O. Miranda🇵🇹 · Lara Sousa🇵🇹

    We develop a semi-analytical model to describe the cosmological evolution of networks of cosmic strings with small-scale structure, by extending the velocity-dependent one-scale model to include an additional lengthscale describing the typical interkink density. We study the impact of the different physical processes involved in the production and removal of small-scale structure from cosmic strings on the attainment of a full linear scaling regime, in which the characteristic lengths of the network and of small-scale structure evolve proportionally to physical time and the root-mean-squared velocity of the network remains constant. We find, using this novel velocity-dependent two-scale model, that quite generally small-scale structure does not prevent the attainment of a linear scaling regime since, even if not enough kinks are carried away when loops are chopped from the network, gravitational backreaction is generally enough to ensure that the interkink density scales. We find, however, that this regime is characterized by a smaller energy density and root-mean-squared velocity when compared to strings without small-scale structure and that this reduction may be significant when scaling is maintained by gravitational backreaction. In this case, we also find that, before reaching full scaling, the network should evolve in a transient quasi-scaling regime, in which its evolution is very similar to that of cosmic strings without small-scale structure.

    ↳ astro-ph.COhep-phPRD(2026)·1 citation
25. 25*

    Review of strongly coupled regimes in gravity with Dyson-Schwinger approach

    Marco Frasca🇮🇹 · Anish Ghoshal🇬🇧

    We analyze various gravity theories involving de-Sitter, quadratic ${\mathcal{R}}^2$ and non-minimally coupled scalar in the light of application of the Dyson-Schwinger technique involving exact background solution of the Green's function. We denote specific set of solutions for the metric to move towards a quantum analysis of the theory. This kind of solutions is identified as conformally flat metric. Such a conclusion naturally arises in the use of the Dyson-Schwinger equations in the study of the Yang-Mills theory through the mapping theorem. We show a sequence of cosmological phase transitions starting from the breaking of such conformal invariance that can be hindered by the presence of the non-minimal coupling.

    ↳ gr-qchep-phhep-thUniverse(2026)·0 citations
26. 26*

    Local Thermalization of SU(2) Lattice Gauge Fields on Quantum Computers

    Jiunn-Wei Chen🇹🇼 · Yu-Ting Chen🇹🇼 · Ghanashyam Meher🇹🇼 · Berndt Müller🇺🇸 · Andreas Schäfer🇩🇪 · Xiaojun Yao🇺🇸

    We simulate the local thermalization dynamics for minimally truncated SU(2) pure gauge theory on linear plaquette chains with up to 151 plaquettes using IBM quantum computers. We study the time dependence of the entanglement spectrum, Rényi-2 entropy and anti-flatness on small subsystems. The quantum hardware results obtained after error mitigation agree with extrapolated classical simulator results for chains consisting of up to 101 plaquettes. Our results demonstrate the feasibility of local thermalization studies for chaotic quantum systems, such as nonabelian lattice gauge theories, on current noisy quantum computing platforms.

    ↳ hep-lathep-phnucl-thquant-ph14 citations
27. 27*

    On the ultraviolet behavior of the invariant charge in quantum electrodynamics

    N.V.Krasnikov🇷🇺

    In this paper we study the ultraviolet behavior of the invariant charge in QED. We show that for complex momenta the invariant charge does not have Landau pole singularity. We can define new invariant charge as real part of standard invariant charge. New invariant charge is limited from above and does not have Landau pole singularity. Also we use the $1/N$ perturbation theory for the investigation of the ultraviolet behavior of the invariant charge. To this aim we consider QED with imaginary charge which is asymptotically free but nonphysical model. In QED with nonphysical imaginary charge we can reliably calculate the ultraviolet asymptotics for the $(1/N{)}^k$ correction to the invariant charge, namely: ${\alpha }_k(\frac{p^2}{{\mu }^2},\alpha )\sim (\ln (\frac{p^2}{{\mu }^2}){)}^{-k-1}$ at $k>1$ and ${\alpha }_1(\frac{p^2}{{\mu }^2},\alpha )\sim (\frac{\ln (\ln (\frac{p^2}{{\mu }^2})}{{\ln }^2(\frac{p^2}{{\mu }^2})})$ at $k=1$. The $1/N$ perturbation theory coincides for QED with imaginary charge and standard QED with real charge. It means in particular that ultraviolet behavior of the $(1/N{)}^k$ correction ${\alpha }_k(\frac{p^2}{{\mu }^2},\alpha )$ in real QED coincides with the corresponding asymptotics for QED with imaginary charge. We propose also to use the modified $1/N$ expansion which is ultraviolet finite. The comparison of the standard QED and nonphysical QED with imaginary charge gives hint that in other non asymptotically free models like supersymmetric QED, scalar QED or Wess-Zumino model ultraviolet asymptotics of the invariant charge coincides with leading log approximtion.

    ↳ hep-thhep-ph1 citation
28. 28*

    Prospect of the NUCLEUS Experiment at Chooz for Coherent Elastic Neutrino-Nucleus Scattering and New Physics Searches

    H. Abele🇦🇹 · G. Angloher🇩🇪 · B. Arnold🇦🇹 · M. Atzori Corona🇮🇹 · A. Bento🇩🇪 · E. Bossio🇫🇷 · F. Buchsteiner🇦🇹 · J. Burkhart🇦🇹 · F. Cappella🇮🇹 · M. Cappelli🇮🇹 · N. Casali🇮🇹 · R. Cerulli🇮🇹 and 53 other authors

    The NUCLEUS experiment aims to measure coherent elastic neutrino-nucleus scattering (CE$\nu$NS) at unprecedentedly low nuclear recoil energies using gram-scale cryogenic calorimeters operated at the Chooz nuclear power plant in France. Access to recoil energies at the $\mathcal{O}(10\mathrm{eV})$ scale enables CE$\nu$NS studies at extremely low momentum transfer and provides enhanced sensitivity to new physics. In this work, we present sensitivity projections for the upcoming NUCLEUS technical and physics runs, incorporating a data-driven treatment of the low-energy excess (LEE) observed during commissioning. We develop a likelihood framework that exploits reactor-power variation to disentangle signal and background in a low signal-to-background regime and to assess the impact of the dominant systematic uncertainties. For the Technical Run with a 7 g CaWO${}_4$ target, we find competitive sensitivity to several scenarios beyond the Standard Model, which do not require a CE$\nu$NS observation. For the Physics Run, assuming complete suppression of the LEE, we project a 4.7 $\sigma$ observation of CE$\nu$NS with a statistical precision of about 20 % in 1 year, enabling a determination of the weak mixing angle at the lowest momentum transfer probed to date with CE$\nu$NS and leading CE$\nu$NS-based constraints on the neutrino charge radius and new mediator models.

    ↳ hep-exhep-phPRD(2026)·2 citations
29. 29*

    Many-body perturbation theory for the nuclear equation of state up to fifth order

    C. Drischler🇺🇸 · K. S. McElvain🇺🇸 · P. Arthuis🇫🇷

    We present an automated, GPU-accelerated framework for many-body perturbation theory (MBPT) calculations of the zero-temperature nuclear equation of state (EOS) based on chiral nucleon-nucleon (NN) and three-nucleon (3N) interactions. Automated diagram generation and evaluation enable the computation of all diagrams up to fifth order in the MBPT expansion at the normal-ordered two-body level in infinite matter, with residual three-body contributions explicitly included up to third order. Multi-GPU acceleration of 3N normal ordering, a novel Monte Carlo integrator (called PVegas), and further advances in high-performance computing enable us to evaluate all 840 fifth-order diagrams with controlled numerical uncertainties. We investigate the MBPT convergence up to fifth order in pure neutron matter (PNM) and symmetric nuclear matter (SNM) for two sets of chiral interactions, study neutron star matter, and present fourth-order results for asymmetric matter including normal-ordered 3N forces. The framework enables systematic MBPT studies with harder interactions and benchmarks against nonperturbative methods. It can be further extended to finite-temperature EOS calculations and to improved uncertainty quantification using emulation and resummation techniques.

    ↳ nucl-thhep-phnucl-ex7 citations
30. 30*

    From friction scaling to an efficient method for estimating bubble wall velocity

    Tomasz Krajewski🇵🇱 · Marek Lewicki🇵🇱 · Marco Merchand🇯🇵 · Ignacy Nałęcz🇵🇱 · Mateusz Zych🇵🇱

    We present a unified description of first-order cosmological phase transition dynamics that links the phenomenological friction model employed in hydrodynamic simulations to the microscopic treatment based on Boltzmann equations. We derive an approximate analytical expression for the chemical potential and demonstrate that the resulting friction parameter $\tilde{\eta }$ follows a simple power-law dependence on the transition strength ($\propto v_n^4/T_n^4$). Incorporating this scaling into a phenomenological framework accurately reproduces the terminal wall velocities obtained from the full microscopic analysis performed using \texttt{WallGo}. This approach offers an efficient method to quantify out-of-equilibrium contributions to friction and reliably estimate bubble-wall velocities.

    ↳ astro-ph.COhep-phJHEP(2026)·4 citations
31. 31*

    Neutrino and electromagnetic signatures from Superluminous Supernovae: a case study for SN 2017egm

    Mainak Mukhopadhyay🇺🇸 · Shigeo S. Kimura🇯🇵 · Indrek Vurm🇪🇪 · Brian D. Metzger🇺🇸

    Superluminous supernovae (SLSNe) are rare transients that are $\sim 10-100$ times more luminous than ordinary stellar explosions, reaching peak optical luminosities $\sim 10^{44}-10^{45}$ erg s${}^{-1}$. The energy source powering SLSNe remains uncertain. In this work, we explore the multi-wavelength and multi-messenger signatures of the scenario in which SLSNe are powered by a newly born millisecond magnetar. We model the dynamical evolution and emission from the coupled system comprised of the magnetar, wind, nebula, and supernova ejecta, consistently evaluating the pair multiplicity of the wind and nebula regions, and the bulk wind Lorentz factor governing the $e^{+}-e^{-}$ injection spectra in the nebula. We compute the thermal and non-thermal electromagnetic signatures, neutrino signatures, and investigate their detection prospects. For SN 2017egm, the nearest observed SLSNe, our prediction for high-energy gamma rays matches the recent detection by Fermi LAT. For neutrinos, using SN 2017egm a canonical SLSNe, we find that in the era of the Vera C. Rubin Observatory, a stacking analysis with upcoming neutrino observatories can lead to $3\sigma$ detection significance of neutrino events from a population of SLSNe within a decade of operation.

    ↳ astro-ph.HEhep-phApJ(2026)·0 citations
32. 32*

    The Two Lives of a Massive Charged Spin-$\frac{3}{2}$ Particle: from Superstrings EFT to Supergravity

    Karim Benakli🇫🇷

    A charged massive spin-$\frac{3}{2}$ field in a constant electromagnetic background admits two familiar realizations. In supergravity, where it is identified with a gravitino, its mass and charge are tied in Planck units. In the decoupled-gravity regime, the two-derivative Fierz--Pauli system describing the first massive open-string modes instead allows arbitrary mass and charge. The gyromagnetic ratio $g=2$ is achieved in both cases through non-minimal Pauli couplings, but these take different forms: they are symmetric in the two chiral sectors in the supergravity system, and chiral-asymmetric in the flat-space one. We construct a continuous family of Fierz--Pauli systems interpolating between these two endpoints. We show that the corresponding second-order equations always reproduce $g=2$ at linear order, but generically contain a chiral $F^2$ term at quadratic order. Its coefficient vanishes precisely at the two endpoint theories. Requiring compatibility with dynamical gravity, or closure for non-constant electromagnetic field strength, then selects the supergravity endpoint. The result clarifies the domains of applicability of the two systems and shows that the maximally asymmetric organization of the decoupled theory cannot be extended unchanged once gravity is dynamical. For comparison, we also analyze a charged massive spin-$2$ field on Einstein--Maxwell backgrounds and exhibit the corresponding closure of the associated lower-spin chain.

    ↳ hep-thgr-qchep-phJHEP(2026)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.