Tue·Apr 28, 2026Tuesday·April 28, 2026

1. 01*

   Amplitude-Based Analysis of QED Radiative Corrections to Electroproduction of $\eta$-Mesons on Protons

   Isabella Illari🇺🇸 · Andrei Afanasev🇺🇸 · William J. Briscoe🇺🇸 · Victor L. Kashevarov🇮🇹 · Axel Schmidt🇺🇸 · Igor I. Strakovsky🇺🇸

   A formalism for radiative correction calculations in exclusive $\eta$ electroproduction on the proton is presented, extending the treatment developed for the pion channel. The EXCLURAD code is used in the radiative correction procedure with EtaMAID-2023 multipole amplitudes. The cross-section correction factor $\delta$ varies by up to $\sim 30\%$ across the resonance region $W=1.49$-$2.0$ GeV at $E_{\mathrm{beam}}=6.535$ GeV, with a local maximum near $W\simeq 1.66$ GeV driven by the $S_{11}(1535)$ and $S_{11}(1650)$ resonances. The beam-spin asymmetry is suppressed by 15-25% at the same kinematics. Numerical results covering $Q^2=0.3$-$4.0$ GeV${}^2$ and the full angular range are provided for kinematics relevant to CLAS12 experiments at Jefferson Lab.

   hep-phnucl-exnucl-thPRD(2026)·0 citations
2. 02*

   Light-front mass operator with dressed quarks

   J. A. O. Marinho🇧🇷 · J. P. B. C. de Melo🇧🇷 · T. Frederico🇧🇷 · W. de Paula🇧🇷

   We construct an effective light-front mass-squared operator for quark-antiquark systems that incorporates quark dressing effects through a running quark mass. Starting from a Minkowski-space quark propagator constrained by lattice-QCD-inspired parametrization, we derive the disconnected light-front resolvent for a light quark-antiquark system using a generalized spectral representation of an individual quark propagator separating out the instantaneous contributions. By projecting the resolvent onto a constituent-quark helicity basis, we obtain an effective dressed mass-squared operator suitable for light-front Hamiltonian approaches. We introduce an effective light-front quark self-energy and analyze its momentum dependence. As an application, we study pion structure using representative light-front wave-function models and compute unpolarized transverse-momentum-dependent distributions, unpolarized parton distribution functions and distribution amplitudes. Our results show that quark dressing induces sizable infrared modifications while preserving controlled ultraviolet behavior, providing a framework to incorporate nonperturbative QCD dynamics into light-front descriptions of hadrons.

   hep-phhep-thPRD(2026)·0 citations
3. 03*

   Mono-Z' Signatures in the B-L Supersymmetric Standard Model at the LHC

   Ali Cici🇹🇷 · Shaaban Khalil🇪🇬 · Stefano Moretti🇬🇧 · Cem Salih Un🇹🇷

   The B-L Supersymmetric Standard Model with Inverse Seesaw (BLSSM-IS) extends the Minimal Supersymmetric Standard Model (MSSM) by incorporating a gauged B-L symmetry, right-handed neutrinos and an additional neutral gauge boson Z'. Searches at the Large Hadron Collider (LHC) constrain the mass of this gauge boson to be as low as only ~ 2.2 TeV in the BLSSM-IS, owing to interference effects with the SM. In this framework, mono-Z' events can arise from the associated production of a Z' boson and a singlet Higgs boson h', where h' subsequently decays into missing energy carried by a pair of the Lightest Supersymmetric Particle (LSP) - either a neutralino or a right-handed sneutrino - which serves as a Dark Matter (DM) candidate. Focusing on leptonic decays of the Z' (electrons and muons), we analyse the kinematic distributions of the final-state leptons and the missing transverse energy in order to extract a signal for this process which is independent of the nature of the BLSSM-IS DM.

   hep-ph0 citations
4. 04*

   $D{\bar{D}}^{\ast }$-$\pi J/\psi$ scatterings of coupled channels for $Z_c(3900)$ channel

   Yukihiro Abe🇯🇵 · Yasuhiro Yamaguchi🇯🇵 · Atsushi Hosaka🇯🇵

   We perform coupled channel analysis for $D{\bar{D}}^{\ast }$, $J/\psi \pi$ and related meson pairs for the $Z_c(3900)$ channel in an effective model of hadrons and quarks. The model incorporates meson exchange potential such as one pion and $D^{(\ast )}$ meson exchanges, and quark exchanges. It turns out that the meson exchange potential is small, while the off-diagonal interactions by the quark exchanges at short distances, particularly for transitions between $D{\bar{D}}^{\ast }$-$J/\psi \pi$ are strong, which plays a main role for the scattering amplitudes for the $Z_c(3900)$ channel, in consistent with the results of the lattice simulations of the HALQCD group.

   hep-phPRD(2026)·0 citations
5. 05*

   Baryon enhancement in jets

   Antonio Ortiz🇲🇽 · Robert Vertesi🇭🇺

   The enhancement of the baryon production relative to mesons in small-collision systems is considered a breakthrough result of the Large Hadron Collider since a similar effect in heavy-ion collisions is understood by invoking the formation of the strongly-interacting quark--gluon plasma. In this letter, a baryon enhancement is reported for $p_{\mathrm{T}}^{\mathrm{ch},\mathrm{jet}}>15$\,GeV/$c$ jets produced in pp collisions at $\sqrt{s}=13$\,TeV simulated with PYTHIA8. The effect can be explained as a transition between quark-initiated jets (low jet multiplicities) to gluon-initiated jets (high jet multiplicities). The present result challenges the interpretation about the multiplicity dependence of the baryon enhancement in terms of collective expansion of the medium and quark recombination.

   hep-ph0 citations
6. 06*

   Coupled-channel study of the three-body $DDK$ and $D^{\ast }{D}^{\ast }K$

   Hai-Peng Xie🇨🇳 · Si-Yi Chen🇨🇳 · Ning Li🇨🇳 · Wei Chen🇨🇳

   We investigate the three-body $DDK$ system with quantum numbers $I(J^P)=\frac{1}{2}(0^{-})$ within a coupled-channel framework that incorporates both $DDK$ and $D^{\ast }{D}^{\ast }K$ configurations. The $D^{(\ast )}{D}^{(\ast )}$ interactions are described using the one-boson-exchange model constrained by the heavy-quark symmetry and fitted to the pole positions of $X(3872)$, $T_{cc}^{+}$, and $Z_c(3900)$. The $D^{(\ast )}K$ interaction is from the chiral effective theory, motivated by the molecular interpretation of $D_{s0}^{\ast }(2317)$, and is further constrained by lattice-QCD results for the $DK$ scattering lengths. The resulting three-body problem is solved using the Gaussian expansion method, while the complex scaling method is employed to search for possible resonant states. We find that coupled-channel effects from $D^{\ast }{D}^{\ast }K$ are negligible, and the $DDK$ system supports a deeply bound state across a wide range of parameters. Depending on the long-range behavior of the $DK$ interaction, an additional shallow state may emerge near the particle-dimer ($D$-$DK$) threshold. The deeply bound state exhibits a compact three-body structure, whereas the shallow state displays characteristic features of a three-body halo configuration. No clear resonance poles are identified within the explored parameter region. Similar results are obtained for the $D^{\ast }{D}^{\ast }K$ system. These findings may provide new insight into few-body dynamics in systems involving charmed mesons and kaons.

   hep-phhep-ex0 citations
7. 07*

   Two-loop quarkonium Hamiltonian in annihilation channel

   Yukinari Sumino (Tohoku U.)🇯🇵 · Takahiro Ueda (Juntendo U.)🇯🇵

   We calculate the two-loop quarkonium Hamiltonian in the annihilation channel within the framework of potential-NRQCD effective field theory. The result agrees with the previous calculation of the corresponding four-quark operator in NRQCD for SU(N) color gauge group. We further obtain an expression with a more general color structure applicable to other gauge groups. Combined with the recently calculated two-loop Hamiltonian in the non-annihilation channel, this completes the full two-loop quarkonium Hamiltonian.

   hep-phPLB(2026)·0 citations
8. 08*

   Some approximate renormalization group invariants for supersymmetric extensions of the Standard Model and the Yukawa unification

   Kirill Krylov🇷🇺 · Daniil Rystsov🇷🇺 · Konstantin Stepanyantz🇷🇺

   For supersymmetric extensions of the Standard Model we construct some expressions that include Yukawa couplings for the third and second generations and receive relatively small quantum corrections. This implies that they slightly depend on scale and are therefore approximate renormalization group invariants. Using these invariants we try to analyse possible relations between the Yukawa couplings at the unification scale $M_X$ as well as the predictions for values of $\text{mbox}tg\beta$ and $\alpha (M_X)$. In particular, we suggest two variants of such relations and investigate whether they agree with the experimental values of elementary particle masses. It is demonstrated that the Yukawa unification for the third and second generations consistent with them can be achieved by adding exotic superfields forming 3 representations $5+\bar{5}$ of the group $SU(5)$ to the MSSM field content. We argue that this may indicate the possible underlying $E_6$ gauge symmetry.

   hep-phhep-th0 citations
9. 09*

   Possible Evidence for Neutral Color-Singlet $q\bar{q}$ Quark Matter from High-Energy Pb-Emulsion Collisions

   Cheuk-Yin Wong🇺🇸

   The invariant mass spectrum of $e^{+}{e}^{-}$ pairs produced in high-energy Pb-emulsion collisions at 160 A GeV at CERN SPS exhibits a highly complex structure of a broad enhancement at 11$\pm$1 MeV with a full width of about 10 MeV, and additional many narrow resonances within the experimental bin width of 2 MeV, including a prominent narrow resonance at 19 $\pm$1 MeV that provides an independent support for the hypothetical X17 particle. We show that the highly complex spectrum may be coherently described as the signatures for the neutral color-singlet $q\bar{q}$ quark matter in both its deconfined phase as well as its confined phase. That is, the broad enhancement at 11$\pm$1 MeV may arise from thermal annihilation of QED(U(1))-deconfined quarks and antiquarks into $e^{+}{e}^{-}$ pairs at the phase transition temperature $T_c$(QED), which can be theoretically estimated to be 4.75 $\pm$ 1.04 MeV from the transitional equilibrium condition. The observed narrow resonances at 3$\pm$1 and 7$\pm$1 MeV may correspond to the QED(U(1))-deconfined $u\bar{u}$ and $d\bar{d}$ Coulomb bound states near their quark rest masses, respectively, whereas the observed narrow resonance at 19 $\pm$ 1 MeV may correspond to the QED(U(1))-confined isoscalar QED meson. The approximate agreement between the theoretical and the experimental spectrum suggests tentatively that both QED(U(1))-confined and QED(U(1))-deconfined neutral color-singlet $q\bar{q}$ quark matter may have been produced in these high-energy Pb-emulsion collision, pending confirmation of the Pb-emulsion collision data. We propose future experiments to confirm or refute these findings.

   hep-phhep-thnucl-th0 citations
10. 10*

    Three regimes/phases of QCD at high T, their symmetries and N_c scaling

    L. Ya. Glozman🇦🇹

    We review recent developments on the QCD phase diagram at small chemical potentials and increasing temperature. There are three regimes/phases in QCD which differ by symmetries, degrees of freedom and N_c scaling: the hadron gas below the chiral restoration temperature T_ch, the stringy fluid between T_ch and the deconfinement temperature T_d and the quark-gluon plasma above T_d.

    hep-phhep-exhep-lathep-th+10 citations
11. 11*

    Kaon Distribution Amplitudes from Euclidean Functional QCD

    Wen Cui🇨🇳 · Dao-yu Zhang🇨🇳 · Chuang Huang🇩🇪 · Wei-jie Fu🇨🇳

    We study the kaon quasi-distribution amplitude (quasi-DA) and distribution amplitude (DA) within the large-momentum effective theory (LaMET) combined with the first-principles functional QCD. Using quark correlation functions and the kaon Bethe-Salpeter amplitude in the Euclidean space from the 2+1 flavour functional QCD [1] as inputs, we obtain the kaon quasi DA in the large longitudinal momentum region with the contour deformation method [2] in the complex plane of momentum. By performing $1/P_z^2$ and $1/P_z^4$ order extrapolations of the kaon quasi-DA for the choices of the maximal longitudinal momentum $P_z^{\max }\in [2,2.5]$ GeV, we obtain a single-peaked and asymmetric kaon DA with the uncertainties arising from the extrapolation interval and ansatz. We find the first and second order moments of the kaon DA, $⟨\xi {⟩}_K=0.020(3)$ and $⟨{\xi }^2{⟩}_K=0.253(12)$, respectively.

    hep-ph3 citations
12. 12*

    Searching for ultralight bosons with Josephson junction interferometry

    Djuna Croon🇬🇧 · Tanmay Kumar Poddar🇬🇧

    Ultralight bosons sourced by macroscopic objects can generate long-range spin-independent and spin-dependent potentials that are accessible to precision interferometry. Such potentials induce phase shifts in Josephson junctions, detectable through precision current measurements. We propose three experimental scenarios to probe photophilic scalar interactions, Lorentz-violating scalar-mediated interactions, and axion-mediated monopole-dipole interactions, depending on the nature (unpolarized or polarized) of the source. The proposed setups provide sensitivities to novel mixed couplings that are largely unconstrained by existing bounds and enables the exploration of new forces at centimeter to micrometer length scales.

    hep-phPRD(2026)·0 citations
13. 13*

    Probing the electron Yukawa coupling via resonant Higgs boson production at FCC-ee via $e^{+}{e}^{-}\to H\to W{W}^{\ast }$ in lepton-plus-jets final states

    Apranik Fatehi🇨🇭 · Reza Jafari Seyedabad🇨🇭 · Amir Amiri🇮🇷 · Kazem Azizi🇮🇷 · David d'Enterria🇨🇭 · Louis Portales🇫🇷 · Michele Selvaggi🇨🇭

    We report a detailed simulation study of the search for $s$-channel Higgs boson production in $e^{+}{e}^{-}$ collisions at a center-of-mass (c.m.) energy of $\sqrt{s}=125\mathrm{GeV}$ at the CERN Future Circular Collider (FCC-ee), as a means to constrain the electron Yukawa coupling, $y_e$. The process of interest is $e^{+}{e}^{-}\to H\to W{W}^{\ast }\to {\ell }^{\pm }\nu +jj$ with four different $W{W}^{\ast }$ final states considered, involving both on- and off-shell $W$ bosons decaying either into dileptons (${\ell }^{\pm }=e^{\pm }$ and ${\mu }^{\pm }$, including those from ${\tau }^{\pm }$ decays) or into dijets ($jj$). Signal and background events are discriminated through a multiclass gradient boosted decision tree exploiting a comprehensive set of kinematic and topological variables across the four final-state categories. Assuming a monochromatized c.m. energy spread of 4.1 MeV, yielding a ${\sigma }_{e^{+}{e}^{-}\to H}=280\mathrm{ab}$ resonant cross section, and an integrated luminosity of $10{\mathrm{ab}}^{-1}$, the analysis achieves a combined statistical significance of 2.0 standard deviations. This corresponds to an upper limit on the coupling modifier ${\kappa }_e=y_e/y_e^{\mathrm{SM}}\lesssim 1.35$ at 95\% confidence level, and provides the most stringent constraint on the electron Yukawa coupling achieved in simulation-based studies to date.

    hep-phhep-ex2 citations
14. 14*

    Selected Topics in Quark-Hadron Physics: From Scalar Nonets to Topological Glueballs

    Chihiro Sasaki🇵🇱

    This contribution reviews recent progress in the low-lying scalar mesons and glueballs. We propose a new classification for the scalar nonet that includes $f_0(980)$ and $a_0(980)$ as the lowest states, while we identify $f_0(1500)$ as a primary glueball candidate. We demonstrate that the production yields of these states in heavy-ion collisions are mutually consistent across statistical, coalescence, and S-matrix frameworks. To investigate their internal structure, we move beyond standard phenomenology by describing glueballs as topological solitons. This approach yields an energy spectrum in excellent agreement with lattice QCD and experimental data, while interpreting $f_0(2470)$ as a tightly bound glueballonium to explain its anomalously long lifetime. This non-perturbative framework provides a predictive basis for the future experimental verification of exotic scalar states.

    hep-phnucl-thActa Phys.Polon.B(2026)·0 citations
15. 15*

    How to understand the $\rho$ resonance from the quark model and $\pi \pi$ $P$-wave phase shift

    Wen-Ze Zhao🇺🇸 · Ru-Hui Ni🇨🇳 · Jia-Jun Wu🇨🇳

    As the lightest isovector vector meson, the $\rho$ meson is an important object for investigating the structure of resonant states in strong interactions. Owing to its strong coupling to the $\pi \pi$ channel and its large decay width, the conventional constituent quark model treatment, in which it is simply regarded as a pure $q\bar{q}$ bound state while the hadronic-channel coupling effects are neglected, is insufficient to fully characterize its physical properties. To this end, in the present work we establish a unified framework for studying the structure and resonant properties of the $\rho$ meson by combining the quark-gluon and hadronic degrees of freedom. At the quark-gluon level, we first determine the parameters of the chiral quark model by refitting a set of narrow mesons for which open Okubo-Zweig-Iizuka-allowed strong-decay channels are absent or strongly suppressed. With these parameters fixed, the bare mass of the $\rho$ meson is obtained and used as the input for the subsequent hadronic-level analysis. At the hadronic level, based on inverse-scattering theory, we construct a model including the coupling between the bare state and the $\pi \pi$ continuum, extract the ${\rho }_0-\pi \pi$ interaction using the $P$-wave $\pi \pi$ scattering phase-shift data, and further calculate the width of the $\rho$ meson as well as the bare-state component in the physical state. The present work also provides a generalizable analytical framework for further studies of other hadronic resonances with significant coupled-channel effects.

    hep-phhep-exPRD(2026)·0 citations
16. 16*

    Role of heavy neutral lepton in lepton number violating $B$ meson decays

    Dhiren Panda🇮🇳 · Manas Kumar Mohapatra🇮🇳 · Rukmani Mohanta🇮🇳

    We study the phenomenology of heavy neutral leptons (HNLs) in $B$-meson decays as probes of physics beyond the Standard Model. Focusing on the leptonic channels $B\to \mu N$ and $B\to \tau N$, we constrain the allowed regions in the $M_N$--$|U_{\ell N}{|}^2$ plane using current experimental data. Using these constraints, we investigate lepton-number violating ($\Delta L=2$) processes mediated by on-shell HNLs, including $B_{(c)}^{-}\to {\pi }^{+}{\mu }^{-}{\mu }^{-}$ and $B_c^{-}\to J/\psi {\pi }^{+}{\mu }^{-}{\mu }^{-}$. For benchmark values $|U_{\mu N}{|}^2=10^{-6}$ and $M_N=2$-- $3\mathrm{GeV}$, the predicted branching ratios lie in the range $\mathcal{O}(10^{-13})$--$\mathcal{O}(10^{-8})$. Among the channels, $B_c^{-}\to {\pi }^{+}{\mu }^{-}{\mu }^{-}$ shows the largest enhancement, while $B_c^{-}\to J/\psi {\pi }^{+}{\mu }^{-}{\mu }^{-}$ is strongly suppressed. These results indicate a clear channel dependence, with $B_c$ modes providing enhanced sensitivity to HNL effects and offering promising avenues for future searches of lepton number violation.

    hep-phPLB(2026)·0 citations
17. 17*

    CP violation in ${\Sigma }^{+}\to p{\ell }^{+}{\ell }^{-}$ within the standard model and beyond

    Xiao-Gang He🇨🇳 · Jusak Tandean🇨🇳 · German Valencia🇦🇺

    The LHCb collaboration has recently observed the rare hyperon decay ${\Sigma }^{+}\to p{\mu }^{+}{\mu }^{-}$. It can also measure the corresponding antihyperon channel with comparable precision and is thus in a position to extract information on $CP$ violation in this mode. Interestingly, the long-distance contributions that dominate it within the standard model provide large absorptive phases that could drive substantial $CP$ violation through interference with potential new-physics contributions. Here we explore this possibility, finding that the decay rate asymmetry is currently allowed to be as high as tens of percent, which can be probed by LHCb in the near future. We additionally consider the same with regard to the dielectron mode ${\Sigma }^{+}\to p{e}^{+}{e}^{-}$ as well as the related radiative one ${\Sigma }^{+}\to p\gamma$.

    hep-phhep-exJHEP(2026)·1 citation
18. 18*

    Same-Sign Tetralepton Signature at $\mu$TRISTAN

    Lin-Kun Yan🇨🇳 · Zhi-Long Han🇨🇳 · Feng-Lan Shao🇨🇳 · Fa-Xin Yang🇨🇳

    Naturally tiny neutrino masses can be explained by the low scale seesaw with heavy neutral lepton $N$ coupling to the neutrinophilic Higgs doublet ${\Phi }_{\nu }$, which obtains a much smaller vacuum expectation value than the standard Higgs doublet $\Phi$. Within this model, the neutrino masses originate from the new Yukawa interaction $y\overline{L}{\tilde{\Phi }}_{\nu }N$. In this paper, we propose the novel same-sign tetralepton signature at the 2 TeV same-sign muon mode ${\mu }^{+}{\mu }^{+}$ of $\mu$TRISTAN. We investigate two distinct channels of this signature, which are both generated by the Yukawa interaction $y\overline{L}{\tilde{\Phi }}_{\nu }N$. One is from the pair production of charged Higgs ${\mu }^{+}{\mu }^{+}\to H^{+}{H}^{+}\to {\mu }^{+}N+{\mu }^{+}N\to {\mu }^{+}{\mu }^{+}jj+{\mu }^{+}{\mu }^{+}jj\to 4{\mu }^{+}+4j$, and the other one is from the single production of charged Higgs ${\mu }^{+}{\mu }^{+}\to {\mu }^{+}N{H}^{+}\to {\mu }^{+}N+{\mu }^{+}N\to {\mu }^{+}{\mu }^{+}jj+{\mu }^{+}{\mu }^{+}jj\to 4{\mu }^{+}+4j$. We then perform a detailed simulation of this same-sign tetralepton signature, and obtain the promising region at $\mu$TRISTAN.

    hep-phhep-ex3 citations
19. 19*

    Double SM-like Higgs production at future $e^{+}{e}^{-}$ colliders in the 3-Higgs Doublet Model under the $S_3$ symmetry

    Emine Yildirim🇹🇷

    In this paper, we present the production of double Standard Model (SM)-like Higgs $(h)$ at the future electron positron colliders within the framework of the $S_3$ model with three Higgs doublets (S3-3H) and no CP violation to describe beyond the SM Higgs Physics. We focus first on the numerically allowed parameter space of the model, taking into account theoretical bounds from perturbative unitarity and vacuum stability, as well as by data at the Large Hadron Collider (LHC) and the Tevatron. Double Higgs production in the S3-3H model can deviate from the SM predictions up to a few orders of magnitude in both the $e^{+}{e}^{-}\to hhZ$ and the $e^{+}{e}^{-}\to hh{\nu }_e{\bar{\nu }}_e$ channels. Thus, our findings indicate that the S3-3H model can lead to sizable deviations from the SM predictions of Higgs production at future $e^{+}{e}^{-}$ colliders. These results highlight the importance of studies at such colliders for searching for physics beyond the SM.

    hep-phInternational Journal of Modern Physics A…·0 citations
20. 20*

    Energy spectrum of magnetic fields from electroweak symmetry breaking

    Károly Seller🇩🇪 · Günter Sigl🇩🇪

    We study the magnetic fields produced in the early Universe during the electroweak symmetry breaking by considering random configurations of an inhomogeneous Higgs field. By exploiting the inherent randomness of the initial configurations the spectrum of the produced magnetic field is essentially analytic, which bypasses the need for costly lattice simulations. On the numerical side, we devise a simulation framework which results in continuous fields capable of resolving the small-scale structure of the fields that was inaccessible for the lattice-based calculation. Finally, by revisiting the effects of statistical isotropy and causality on the spectrum, we define general correlation functions that are then fitted to the simulation data and compared to the analytic results.

    hep-ph0 citations
21. 21*

    Phenomenology of Vector Dark Matter produced by a First Order Phase Transition

    Malcolm Fairbairn🇬🇧 · William S. A. Shellard🇬🇧

    Both scalar and vector dark matter can be produced during a cosmological first order phase transition if the dark matter is coupled to the field undergoing the transition. Both kinds of particle are also produced by the plasma through the normal freeze out scenario. For different dark matter masses, we identify the regions of parameter space where there are significant deviations from the normal freeze out scenario and discover there are some rather general predictions. For dark matter particles in the traditional thermal relic GeV-TeV window, dark sector phase transitions around a GeV affect scalar dark matter and dark sector phase transitions around 10 MeV affect vector dark matter abundances (and therefore should take place in a dark sector). When the phase transitions are in the interesting temperature range, the normal range of dark matter masses are different to those predicted by thermal freeze out. We calculate the expected gravitational wave signal of these phase transitions.

    hep-ph1 citation
22. 22*

    Non-perturbative heavy quark diffusion coefficients in arbitrarily magnetized quark-gluon plasma

    Debarshi Dey🇨🇳 · Aritra Bandyopadhyay🇷🇴 · Yifeng Sun🇨🇳 · Santosh K. Das🇮🇳

    Heavy quark (HQ) momentum ($\kappa$) and spatial diffusion ($D_s$) coefficients are computed in a non-perturbative thermal QCD medium in the presence of a background magnetic field of arbitrary strength. Both perturbative and non-perturbative effects are incorporated via the in-medium HQ potential, obtained from the resummed gluon propagator. We find that the momentum diffusion coefficients become anisotropic even in the static heavy quark limit, with the magnetic field direction defining the axis of anisotropy. This anisotropy originates from restrictions on longitudinal momentum diffusion in the gluon spectral function, and naturally leads to two spatial diffusion coefficients ($D_s^L$, $D_s^T$). Non-perturbative effects are found to be dominant at low temperatures. These results provide a more consistent input for Langevin based calculations of the heavy quark directed flow at RHIC and LHC energies.

    hep-phnucl-thPLB(2026)·0 citations
23. 23*

    Mass spectra of charged mesons and the quenching of vector meson condensation via exact phase-space diagonalization

    Jingyi Chao🇨🇳 · Kun Xu🇨🇳

    We investigate the dynamics and mass spectra of charged pseudoscalar (${\pi }^{+}$) and vector (${\rho }^{+}$) mesons in a background magnetic field at finite temperature using the two-flavor Nambu-Jona--Lasinio (NJL) model. By employing a quark propagator that isolates the Schwinger phase from its Landau level expansion, we formulate an exact non-commutative phase-space framework utilizing the Wigner-Weyl transform and the Moyal star product. This approach enables the algebraic diagonalization of the Bethe-Salpeter equations for composite states with asymmetric fractional constituent charges. For the pseudoscalar channel, we analytically verify the exact cancellation between the dynamical random phase approximation spatial sum rules and the vacuum gap equation. This identity preserves the generalized Goldstone theorem, causing the ${\pi }^{+}$ pole mass to strictly track the kinematic zero-point energy drift at order of $eB$. In the vector channel, our full phase-space evaluation reveals that the Zeeman spin-splitting emerges dynamically from microscopic threshold truncations governed by the chiral Dirac algebra. Notably, we find that the tachyonic instability of the spin-aligned ${\rho }^{+}$ state is quenched. The magnetic catalysis of the chiral condensate drives the continuum threshold ($2M$) upwards, overtaking the Zeeman attraction and preventing vector meson condensation within this mean-field framework. Furthermore, finite-temperature evaluations show a monotonic thermal suppression of the meson masses driven by Pauli blocking, yet all modes remain bound without undergoing Mott dissociation prior to chiral symmetry restoration.

    hep-ph1 citation
24. 24*

    Nucleon decays into one lepton plus two non-strange mesons

    Wei-Qi Fan🇨🇳 · Yi Liao🇨🇳 · Xiao-Dong Ma🇨🇳

    Nucleon decays into a lepton and two pseudoscalar mesons represent key channels for probing baryon number violation, complementing conventional two-body modes. In this Letter, we model-independently correlate two- and three-body processes within the framework of low-energy effective field theory, performing a global analysis that avoids single-operator-dominance assumption. We derive significantly improved bounds on 15 three-body modes with a lepton ($e^{+},{\mu }^{+},\hat{\nu }=\nu /\bar{\nu }$) and two non-strange mesons ($\pi ,\eta$). For charged-lepton modes, our lower limits on partial lifetimes (${\Gamma }^{-1}$) surpass current Particle Data Group (PDG) values by more than three orders of magnitude. For 5 (anti)neutrino modes, we establish for the first time ${\Gamma }^{-1}\gtrsim 10^{34}\mathrm{yr}$. Additionally, our analysis improves constraints on two-body processes $n\to e^{+}{\pi }^{-}$, $n\to {\mu }^{+}{\pi }^{-}$, and $p\to \hat{\nu }{\pi }^{+}$ by approximately a factor of 2 compared to the PDG limits. These results highlight the importance of leveraging correlations among different processes to better probe new physics, enabling more stringent constraints on experimentally challenging processes from well-measured ones.

    hep-ph3 citations
25. 25*

    On the Two $R$-Factors in the Small-$x$ Shockwave Formalism

    Yuri V. Kovchegov🇺🇸 · M. Gabriel Santiago🇺🇸 · Huachen Sun🇺🇸

    There are two $R$-factors frequently used in the phenomenology of exclusive processes at small values of the Bjorken $x$ variable. One $R$-factor takes into account the effects of non-zero longitudinal momentum transfer, which is assumed to be zero in the dipole scattering amplitude. Another $R$-factor accounts for the real part of the elastic scattering amplitude which is often neglected, with the standard dipole scattering amplitude giving only the imaginary part of the elastic amplitude. In this work we present two new theoretical developments aimed at eliminating the need for the two $R$-factors. We argue that the $R$-factors can be replaced by (i) modifying the argument of the dipole scattering amplitude and by (ii) augmenting the initial conditions for its non-linear small-$x$ evolution. Specifically, we show that to account for the effects of non-zero skewness $\xi$, one has to replace the rapidity argument $Y=\ln (1/x)$ of the eikonal dipole amplitude $N$ and the odderon dipole amplitude $\mathcal{O}$ by $Y=\ln \min \left\{1/|x|,1/|\xi |\right\}$. The prescription applies to the elastic scattering cross sections, as well as for calculations of the Generalized Parton Distributions and Generalized Transverse Momentum Dependent parton distributions at small $x$ and at small but non-zero skewness $\xi$. We also show that the real part of the scattering amplitude, proportional to Im~$N$, which is intimately connected to the signature factor of the amplitude, can be accounted for by a more careful evaluation of the initial condition for the evolution and by writing the non-linear evolution equation in an integral form. One can similarly construct Im~$\mathcal{O}$ for the odd-signature odderon amplitude. We hope that future implementation of our prescriptions presented here will eliminate the need for both phenomenological $R$-factors.

    hep-phnucl-th5 citations
26. 26*

    Next-to-next-to-leading QCD corrections to the ${\mathbf{B}}^{+}$-${\mathbf{B}}_{\mathbf{d}}^0$, ${\mathbf{D}}^{+}$-${\mathbf{D}}^0$, and ${\mathbf{D}}_{\mathbf{s}}^{+}$-${\mathbf{D}}^0$ lifetime ratios

    Francesco Moretti🇩🇪 · Ulrich Nierste🇩🇪 · Pascal Reeck🇩🇪 · Matthias Steinhauser🇩🇪

    The total decay widths of heavy mesons can be systematically calculated in terms of an expansion in the two parameters $1/m_Q$ and ${\alpha }_s(m_Q)$, where $Q=c,b$ denotes the heavy quark. The dominant contributions to meson lifetime splittings stem from terms which are suppressed by $1/m_Q^3$ with respect to the leading universal contribution to the total decay width. We calculate three-loop contributions of order ${\alpha }_s^2/m_q^3$ to the lifetime ratios $\tau (B^{+})/\tau (B_d^0)$, $\tau (D^{+})/\tau (D^0)$, and $\tau (D_s^{+})/\tau (D^0)$ in the limit of exact isospin and V-spin symmetry, respectively. Furthermore, we present new ${\alpha }_s/m_q^3$ corrections to the Cabibbo-suppressed terms in $\tau (B^{+})/\tau (B_d^0)$. Combining our perturbative coefficients with hadronic matrix elements calculated from Heavy Quark Effective Theory sum rules, we find $\tau (B^{+})/\tau (B_d^0)=1.072\pm 0.024$. Using hadronic matrix elements from a recent lattice QCD calculation we find $\tau (D^{+})/\tau (D^0)=2.344\pm 0.170$ and $\tau (D_s^{+})/\tau (D^0)=1.289\pm 0.042$. We find good agreement of our predictions with experimental data, which constitutes a successful probe of the calculations of hadronic matrix elements and permits estimates of the unknown $1/m_Q^4$ contributions as well as the V-spin breaking terms in $\tau (D_s^{+})/\tau (D^0)$.

    hep-ph3 citations
27. 27*

    Accidental Peccei-Quinn Symmetry from Chiral Gauge Symmetry and Mirror QCD

    Hajime Fukuda🇯🇵 · Keisuke Harigaya🇺🇸

    We present a solution to the strong CP problem in which a simple chiral U(1) gauge symmetry gives rise to an accidental Peccei-Quinn symmetry that is both explicitly and spontaneously broken by mirror QCD dynamics, yielding a framework without massless fermions or a light QCD axion. The model contains no stable domain walls or colored relics, and it accommodates a sufficiently high reheating temperature to account for the baryon asymmetry of the Universe via leptogenesis. Metastable domain walls and first-order mirror QCD phase transition generate a stochastic background of primordial gravitational waves. Additionally, one of the pseudo-Nambu-Goldstone bosons serves as a viable WIMP dark matter candidate. The gauge boson associated with the chiral U(1) gauge symmetry, which kinetically mixes with the Standard Model hypercharge gauge boson, provides a vector portal connecting dark matter to the Standard Model and plays a central role in the dark-matter phenomenology. Colored pseudo-Nambu-Goldstone bosons can be probed at the LHC through searches for dijet resonances, jets plus missing energy, multijet events with leptons, and displaced vertices.

    hep-phhep-ex1 citation
28. 28*

    Passage of particles through matter and the effective straggling-function: High-fidelity accelerated simulation via Physics-Informed Machine Learning

    Oleksandr Borysov🇮🇱 · Rotem Dover🇮🇱 · Eilam Gross🇮🇱 · Nilotpal Kakati🇮🇱 · Noam Tal Hod🇮🇱

    High-fidelity simulation of particle-matter interactions provides the essential theoretical reference for diverse physics disciplines, yet generating synthetic datasets at the scale of current and future experiments has become prohibitive. Here, we introduce PHIN-GAN, a novel physics-informed generative adversarial network designed to address this challenge. We derive a set of analytical probability density functions, that effectively describe the ``straggling function'' identified with Landau. For the first time, this enables their continuous evaluation across the entire phase-space. These analytical forms are leveraged to enforce a parametric distribution-level learning objective. Rooted in first principles, PHIN-GAN offers a generalizable, interpretable and scalable proof-of-concept approach for a lossless generative model that maintains the high fidelity of the standard-bearer for simulating such interactions, namely GEANT4, at a fraction of the computational cost.

    ↳ hep-exhep-phphysics.comp-ph0 citations
29. 29*

    On the Cancellation of Nuclear Effects in the Valence Region

    S.A. Kulagin🇷🇺 · R. Petti🇺🇸

    Deep-inelastic $e/\mu$ scattering data on targets ranging from deuterium to lead indicate that nuclear modifications to the structure functions of bound nucleons are minimal in the kinematic region where valence quark distributions peak. A global analysis of measurements of the isoscalar cross-section ratios ${\sigma }^A/{\sigma }^{{}^2\text{H}}$ in the range $0.25\le x\le 0.35$ reveals a remarkable cancellation of nuclear effects across all nuclei, yielding a mean value of $0.9988\pm 0.0023$. We discuss these results and explore potential interpretations within a microscopic model for the nuclear modifications of the structure functions.

    ↳ nucl-thhep-exhep-phnucl-ex0 citations
30. 30*

    Parametric Resonance in ${\varphi }^4$ Preheating: An Exact Numerical Study

    Hrisikesh Thakur🇮🇳 · Malay K. Nandy🇮🇳

    Preheating after inflation proceeds through parametric resonance, leading to efficient particle production in scalar field models. In this work, we investigate the structure of parametric resonance in the ${\varphi }^4$ chaotic inflationary model during the preheating phase by performing a fully numerical analysis of the coupled dynamical equations governing the inflaton field and the mode function of the produced particles, thereby avoiding the approximations commonly employed in earlier studies. Our results reveal resonance patterns that differ significantly from those obtained with approximate analytical treatments. In the weak coupling regime, short-wavelength modes rapidly settle into oscillations with nearly constant amplitude, while the corresponding occupation numbers approach saturation. However, the long-wavelength modes exhibit gradual amplitude growth, with occupation numbers transitioning into a non-linear oscillatory regime. As the coupling strength increases, the dynamics becomes increasingly nonlinear, leading to the emergence of stochastic behavior. In the strong coupling regime, short-wavelength modes display a step-like (staircase) evolution in the occupation number, indicative of intermittent bursts of particle production. However, the long-wavelength modes exhibit a more gradual, monotonic growth with small superimposed fluctuations. These findings highlight the rich, coupling-dependent, structure of parametric resonance in the quartic inflationary model and underscore the importance of exact numerical treatment in accurately capturing preheating dynamics.

    ↳ astro-ph.COgr-qchep-ph0 citations
31. 31*

    Testing Scalar Field Dark Matter models in M31 galaxy through the Rotation Curve analysis

    Gulnara Suliyeva🇰🇿 · Kuantay Boshkayev🇰🇿 · Talgar Konysbayev🇰🇿 · Yergali Kurmanov🇰🇿 · Guldana Rabigulova🇰🇿

    We explore the viability of scalar field dark matter halo models through the rotation curve analysis of the Andromeda galaxy (M31), taking into account a realistic description of its baryonic structure. The mass model includes a stellar disk described by the Freeman profile and two alternative bulge configurations: a classical single de Vaucouleurs bulge and a two-component structure consisting of inner and main bulges modeled by exponential sphere profiles. The dark matter halo is modeled using three scalar field motivated models: fuzzy dark matter (FDM), Bose-Einstein condensate and multistate scalar-field dark matter. The model parameters are determined through the Levenberg-Marquardt nonlinear least-squares fitting, and the relative performance of the models is evaluated using the Bayesian Information Criterion which allows a direct comparison with previous phenomenological halo studies performed for the same galaxy. We find that the two-bulge baryonic configuration ensures a better statistical description of the M31 rotation curve, independently of the adopted halo model. The results also suggest that, within scalar field dark matter scenarios, smooth cored halos, such as FDM, provide the most consistent description of the M31 kinematics.

    ↳ astro-ph.COgr-qchep-ph0 citations
32. 32*

    Smooth Threshold Effects from Dimensional Regularization

    Yannick Kluth🇨🇦

    We suggest a non-minimal renormalization scheme based on dimensional regularization that naturally incorporates threshold effects of heavy particles. By renormalizing couplings and masses to subtract all poles in $d\ge 4$, the resulting scheme is mass-dependent and circumvents shortcomings of mass-independent schemes like minimal subtraction. At the same time, many advantages of minimal subtraction such as gauge independence are retained. Through explicit one-loop computations in QCD, we demonstrate that this scheme reduces to minimal subtraction at high energies while providing smooth transitions at particle thresholds and implementing the Appelquist-Carazzone theorem. Potential future applications and extensions are discussed.

    ↳ hep-thhep-phPLB(2026)·1 citation
33. 33*

    Relative velocity in special relativity and quantum field theory

    David Garfinkle🇺🇸

    A derivation of the relative velocity used in the definition of the relativistic cross-section is given in terms of manifestly Lorentz invariant quantities. Along the way we find that there is a certain arbitrariness in the usual definition of cross-section.

    ↳ gr-qchep-ph0 citations
34. 34*

    Weyl anomaly induced transport in hydrodynamics

    Shi-Zheng Yang🇨🇳 · Jian-Hua Gao🇨🇳 · Zuo-Tang Liang🇨🇳 · Georgy Yu. Prokhorov🇷🇺 · Shi Pu🇨🇳 · Oleg V. Teryaev🇷🇺 · Valentin I. Zakharov🇷🇺

    We show that the Weyl (trace) anomaly gives rise to a new non-dissipative vector current in accelerated relativistic fluids. The anomaly uniquely fixes the second-order transport coefficient governing the coupling between the electromagnetic field and the fluid acceleration. We derive this result by extending hydrodynamic anomaly matching to include the trace anomaly, and independently reproduce it in boundary quantum field theory by treating the Rindler horizon of an accelerated observer as an effective boundary. From the boundary perspective, the electric- and magnetic-field sectors correspond to screening and vacuum magnetization effects near the boundary. In the local rest frame, the electric-field contribution induces an additional charge density, while the magnetic-field contribution generates a transverse current with a Nernst-like, more generally thermomagnetic Hall-like, tensor structure. Our results reveal a new class of anomaly-induced transport governed by the trace anomaly.

    ↳ hep-thhep-phnucl-th1 citation
35. 35*

    Bounds on nonlinear effective field theories via resurgent relative entropy

    Pietro Conzinu🇮🇹 · Daiki Ueda🇮🇱

    We study nonlinear effective field theories (EFTs) with factorially growing perturbative expansions, focusing on a class in which the relative entropy encodes an infinite tower of higher-dimensional operators. Using the resummed relative entropy, we derive bounds on EFT coefficients: the non-negativity of the resummed relative entropy fixes the sign of their asymptotic growth, while its violation signals nonperturbative effects such as instabilities. In fermionic QED, analytic continuation from Euclidean to Minkowski spacetime yields a concrete example: the Schwinger effect, a nonperturbative instability captured by the resummed relative entropy.

    ↳ hep-thhep-ph1 citation
36. 36*

    Asymptotic regularization method. A constructive approach

    Christian Durán Romero🇪🇸 · Luis J. Garay🇪🇸 · Mercedes Martín-Benito🇪🇸 · Rita B. Neves🇬🇧

    We introduce a new regularization scheme for divergent integrals in quantum field theory. The framework is based on the structural decomposition of the integrand asymptotic expansion, which distinguishes between contributions that drive UV singularities and those that remain finite. This asymptotic regularization method isolates the genuinely singular sector and enables a consistent subtraction of divergences while maintaining covariance and gauge symmetry. In single-scale theories, we show that the renormalized quantities exhibit a non-local logarithmic dependence uniquely determined by the UV asymptotics, offering a derivation of logarithmic terms that is independent of standard renormalization-group flows. Because it relies only on asymptotic structure rather than on standard relativistic power counting, the method is naturally applicable to theories with modified dispersion relations and non-standard UV scaling. Although formulated here for ultraviolet divergences, the underlying strategy extends straightforwardly to infrared singularities.

    ↳ hep-thgr-qchep-ph1 citation
37. 37*

    Chiral Magnetic effect as the anomaly in the transverse axial vector Ward Identity

    Fei Gao🇨🇳 · Yi Lu🇨🇳 · Minghui Ding🇨🇳 · Xinyang Wang🇺🇸 · Yuxin Liu🇨🇳

    Through analyzing the quark propagator under the magnetic field, we establish that the axial anomaly originates from an additional Dirac structure in quark propagator induced by the magnetic field. This Dirac structure also allows one to connect the axial anomaly with the topological properties of the system by checking the axial vector Ward identity. For the tree level propagator, we reproduce the result of the anomalous axial current as in the Dirac Hamiltonian approach and kinetic theory. Particularly, we confirm that the chiral magnetic effect (CME) comes from the same term that is in charge of the axial anomaly, specifically, as the anomaly of the transversal axial vector Ward Identity. The identity guarantees that the CME conductivity $C_{\mathrm{CME}}$ is a constant as $C_{\mathrm{CME}}=\frac{1}{2{\pi }^2}$, and is robust against the temperature, chemical potential, magnetic field and also interaction. Finally, we verify this numerically by applying the full quark propagator under magnetic field calculated from the functional QCD methods.

    ↳ hep-thhep-phnucl-ex1 citation
38. 38*

    SWIM: Stochastic Warm Inflation Module to generate and analyse Warm Inflationary power spectrum

    Umang Kumar🇮🇳 · Suratna Das🇮🇳

    Numerical analysis to determine the form of the scalar power spectrum in Warm Inflationary paradigm is inevitable. One further needs numerical techniques to analyse any Warm Inflation model with the current observational data through the MCMC codes that are available publicly, like COSMOMC or Cobaya. We present SWIM (Stochastic Warm Inflation Module) written in C++ and Python, that not only helps generate the Warm Inflationary scalar power spectrum, either semi-analytically or fully numerically, but also is integrated with Cobaya enabling the user to constrain the model parameters with current CMB data and thus to put any Warm Inflation model to test. SWIM numerically solves the standard stochastic perturbation equations of Warm Inflation without any approximations, uses machine learning techniques to speed up the MCMC analysis while analysing the fully numerical power spectrum that significantly reduces the computational cost, and is able to accommodate any Warm Inflation model with any form of inflationary potential and dissipative coefficient for numerical analysis. We show that SWIM, in most of the cases, outperforms other numerical codes on Warm Inflation that are designed to yield only the semi-analytical power spectrum as far as the runtimes are concerned. We further point out that there can be situations where the semi-analytical way of determining the scalar power spectrum in Warm Inflation can fall short, and one needs the full numerical power spectrum for parameter estimation given the observational data. In such cases, SWIM is the only code available so far that is designed to perform the task. Hence, SWIM offers a complete numerical platform for thorough analysis of Warm Inflation models against the current cosmological data. SWIM has been made publicly available at https://github.com/umg-kmr/SWIM.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2026)·2 citations
39. 39*

    JWST Constraints on Primordial Magnetic Fields

    Malcolm Fairbairn🇬🇧 · María Olalla Olea-Romacho🇬🇧 · Juan Urrutia🇪🇪 · Ville Vaskonen🇪🇪

    Primordial magnetic fields (PMFs) enhance small-scale structure formation through the Lorentz force acting on baryons, boosting the abundance of low-mass halos and their hosted galaxies. We show that the reionisation history calibrated with the UV luminosity function (UVLF) provides stringent bounds: strong PMFs induce a characteristic double reionisation at $z\approx 24$ that is incompatible with CMB measurements of the optical depth, yielding $\sqrt{⟨B^2⟩}<0.27\mathrm{nG}$ and $<0.18\mathrm{nG}$ for $n_B=-2$ and $n_B=2$ respectively at $95\%\mathrm{CL}$ using Planck priors on $\tau$. This establishes early galaxy observables as among the most sensitive probes of PMFs in Gaussian, non-helical scenarios.

    ↳ astro-ph.COhep-ph0 citations
40. 40*

    spectroxide: A code package for computing cosmic microwave background spectral distortions

    Ethan Baker🇺🇸 · Hongwan Liu🇺🇸 · Siddharth Mishra-Sharma🇨🇭

    We present spectroxide, a code package for computing cosmic microwave background spectral distortions in which all $\sim 14,500$ lines of Rust code, Python interface, and $\sim 400$ automated tests were written by an AI assistant (Claude Code) under human physicist supervision. The solver evolves the photon Boltzmann equation under Compton scattering, double Compton emission, and Bremsstrahlung from $z\sim 5\times 10^6$ to the present, computing spectral distortions from arbitrary heat and photon injection within this redshift range. No fully open-source code of this kind is publicly available; we validate against analytic limits, published spectra, and publicly available precomputed Green's function tables. We document the development as a case study in AI-assisted scientific computing, highlighting how domain expertise caught physics bugs (incorrect dimensional prefactors, near-cancellation errors) that evaded the full automated test suite, and provide recommendations for best practices in human--AI collaborative development of scientific software. We make spectroxide publicly available on GitHub.

    ↳ astro-ph.COastro-ph.IMcs.AIhep-ph1 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.