Wed·Oct 1, 2025Wednesday·October 1, 2025

1. 01*

   Cosmic domain walls on a lattice: illusive effects of initial conditions

   I. Dankovsky🇷🇺 · S. Ramazanov🇷🇺 · E. Babichev🇫🇷 · D. Gorbunov🇷🇺 · A. Vikman🇨🇿

   Evolution of cosmic domain walls (DWs) settles to the scaling solution, which is often assumed to be independent of initial conditions. However, lattice simulations performed in this work reveal a clear dependence of the scaling DW area on the initial configuration of the sourcing scalar field, specifically, its infrared (IR) properties. Namely, the DW area grows as one suppresses IR modes in the initial scalar field spectrum. This growth is saturated, when the area parameter $\xi$ commonly used in the literature reaches the value ${\xi }_{max}\approx 1.2$. The dependence of $\xi$ on IR modes is argued to be of non-physical origin: it is likely to be due to effects of the lattice boundary. Assuming that physically the memory of initial conditions is erased, one recognizes $\xi \approx 1.2$ obtained in the situation with maximally suppressed IR modes as a genuine universal value of the area parameter in the scaling regime. We demonstrate that ignorance about initial conditions may affect predictions for the energy density of gravitational waves by the factor five. The spectral shape of gravitational waves is also affected by the choice of initial conditions, most notably in the low-frequency part. Likewise, we revisit annihilation of DWs under the influence of a potential bias. It has been previously found in Ref. [19] that the annihilation happens significantly earlier compared to the estimate based on the simple balance between the potential bias and surface energy density. We further support this observation and show that the tendency towards an earlier annihilation gets even stronger upon removing IR modes in simulations.

   hep-phastro-ph.COhep-thPRD(2025)·9 citations
2. 02*

   Extra Radiation Cosmologies: Implications of the Hubble Tension for eV-scale Neutrinos

   Helena García Escudero🇺🇸 · Kevork N. Abazajian🇺🇸

   We present a new analysis on sterile neutrino cosmologies using the Dark Energy Spectroscopic Instrument (DESI) second data release (DR2) baryon acoustic oscillation (BAO) measurements in combination with cosmic microwave background (CMB), CMB lensing, and supernova data. We show that BAO observables are intrinsically less sensitive to the combined effects of relativistic energy density, $N_{\mathrm{eff}}$, and the sum of neutrino masses, $\Sigma m_{\nu }$, which are both augmented in sterile neutrino cosmologies. With SH0ES local expansion rate, $H_0$, data, we find $N_{\mathrm{eff}}=3.43\pm 0.13$, reducing the Hubble tension to $2.4\sigma$. For a 0.1 eV sterile neutrino, we find $N_{\mathrm{eff}}=3.50$ as the best fit. For this representative $N_{\mathrm{eff}}$, we find an upper limit of $m_s<0.17$ eV (95% CL), greater than a factor of four weaker than standard constraints on $\Sigma m_{\nu }$. When SH0ES is included, light sterile neutrinos with masses $m_s\simeq 0.1$-$0.2$ eV are favored at $\gtrsim 3\sigma$, whereas eV-scale sterile masses remain strongly excluded by the data in the cosmologies we study. Our findings confirm our previous results that partially thermalized sub-eV sterile neutrinos are preferred by the SH0ES $H_0$ data. The preferred $m_s$ mass scale overlaps with, but is not identical to, that favored in neutrino oscillation solutions to short-baseline anomalies.

   hep-phastro-ph.COPRD(2026)·5 citations
3. 03*

   Temperature derivative divergence of the electric conductivity and thermal photon emission rate at the critical end point from holography

   Yi-Ping Si🇨🇳 · Danning Li🇨🇳 · Mei Huang🇨🇳

   The thermal photon emission rate $\frac{d\Gamma }{dk}$ and DC eletric conductivity ${\sigma }_Q$ of the strongly coupled quark-gluon plasma (sQGP) are investigated around the critical end point in a $N_f=2+1$ holographic QCD model with parameters obtained from machine-learning. It is found that both thermal photon emission rate and eletric conductivity grow most obviously around $T_c$, which agrees with the previous studies, and the result of eletric conductivity at zero chemical potential resembles the lattice results. Moreover, it is found that both the temperature derivative of the eletric conductivity and thermal photon emission rate diverge at the critical end point.

   hep-phPRD(2026)·1 citation
4. 04*

   Nonlocal effective field theory and its applications

   P. Wang🇨🇳 · Zhengyang Gao🇨🇳 · Fangcheng He🇺🇸 · Chueng-Ryong Ji🇺🇸 · W. Melnitchouk🇺🇸 · Y. Salamu🇨🇳

   We review recent applications of nonlocal effective field theory, focusing in particular on nonlocal chiral effective theory and nonlocal quantum electrodynamics (QED), as well as an extension of nonlocal effective theory to curved spacetime. For the chiral effective theory, we discuss the calculation of generalized parton distributions (GPDs) of the nucleon at nonzero skewness, along with the corresponding gravitational (or mechanical) form factors, within the convolution framework. In the QED application, we extend the nonlocal formulation to construct the most general nonlocal QED interaction, in which both the propagator and fundamental QED vertex are modified due to the nonlocal Lagrangian, while preserving the Ward-Green-Takahashi identities. For consistency with the modified propagator, a solid quantization is proposed, and the nonlocal QED is applied to explain the lepton $g-2$ anomalies without the introduction of new particles or interactions. Finally, with an extension of the chiral effective action to curved spacetime, we investigate the nonlocal energy-momentum tensor and gravitational form factors of the nucleon with a nonlocal pion-nucleon interaction.

   hep-phhep-exnucl-thSymmetry(2026)·1 citation
5. 05*

   Magnetic Helicity, Magnetic Monopoles, and Higgs Winding

   Hajime Fukuda🇯🇵 · Yuta Hamada🇯🇵 · Kohei Kamada🇨🇳 · Kyohei Mukaida🇯🇵 · Fumio Uchida🇯🇵

   Changes in magnetic helicity are often discussed across a variety of fields, from condensed matter physics to early universe cosmology. It is frequently stated that the helicity change is given by the integral of the gauge field strength tensor and its dual over spacetime, $\int F\wedge F$. However, this is incorrect when magnetic monopoles once exist in the spacetime. In this paper, we show the correct formula of the helicity change in such a case for the Maxwell theory with the magnetic monopoles. We also discuss what happens when we embed the Maxwell theory with magnetic monopoles into non-Abelian gauge theories. We show that a similar formula holds for the 't Hooft--Polyakov monopole. In particular, we find the winding numbers and the zeroes of the Higgs field in the non-Abelian gauge theory play a crucial role in the helicity change. The same discussion is also applicable to the electroweak theory, and we discuss the implication of our findings to the baryon number change via the chiral anomaly in the early universe.

   hep-phastro-ph.COhep-thJHEP(2026)·5 citations
6. 06*

   Strong decays of the $D{K}^{\ast }$ and $\bar{D}{K}^{\ast }$ molecular states

   Zi-Li Yue🇨🇳 · Cheng-Jian Xiao🇨🇳 · H. García-Tecocoatzi🇲🇽 · Dian-Yong Chen🇨🇳 · Elena Santopinto🇮🇹

   Inspired by the abundant structure near the threshold of the $D^{(\ast )}{K}^{(\ast )}/{\bar{D}}^{(\ast )}{K}^{(\ast )}$, we estimate the strong decay properties of the $T_{c\bar{s}1}^{f/a}$ and $T_{\bar{c}\bar{s}1}^{f/a}$ with $I(J^P)=0/1(1^{+})$ in $D{K}^{\ast }$ and $\bar{D}{K}^{\ast }$ molecular scenarios in the present paper. By employing the effective Lagrangian approach, the widths of the processes $T_{c\bar{s}1}^f\to D^{\ast }K,D_s^{\ast }\eta ,DK\pi$, $T_{c\bar{s}1}^a\to D^{\ast }K,D_s^{\ast }\pi ,DK\pi$, and $T_{\bar{c}\bar{s}1}^{f/a}\to {\bar{D}}^{\ast }K,\bar{D}K\pi$ are estimated. Considering the present estimations, we propose to search for $T_{c\bar{s}1}^{f/a}$ states in $D^{\ast }K$ and $D_s^{\ast }\pi /D_s^{\ast }\eta$ mass invariant spectra. Their ratios may serve as an important test of the molecular scenario.

   hep-phEPJC(2025)·1 citation
7. 07*

   Efficient tau-pair invariant mass reconstruction with simplified matrix element techniques

   Artur Kalinowski🇵🇱 · Wiktor Matyszkiewicz🇵🇱

   The quality of the invariant mass reconstruction of the di-{\tau} system is crucial for searches and analyses of di-{\tau} resonances. Due to the presence of neutrinos in the final state, the {\tau} {\tau} invariant mass cannot be calculated directly at hadron colliders, where the longitudinal momentum sum constraint cannot be applied. A number of approaches have been adopted to mitigate this issue. The most general one uses Matrix Element (ME) integration for likelihood estimation, followed by invariant mass reconstruction as the value maximizing the likelihood. However, this method has a significant computational cost due to the need for integration over the phase space of the decay products. We propose an algorithm that reduces the computational cost by two orders of magnitude, while maintaining the resolution of the invariant mass reconstruction at a level comparable to the ME-based method. Moreover, we introduce additional features to estimate the uncertainty of the reconstructed mass and the kinematics of the initial {\tau} leptons (e.g., their momenta).

   hep-phhep-exNucl.Instrum.Meth.A(2026)·6 citations
8. 08*

   A Supersymmetric Extension of Axionic Electrodynamics: From Axions and Photons to Axinos and Photinos

   C. Roldán-Domínguez🇧🇷 · H. Belich🇧🇷 · W. Spalenza🇧🇷 · A. L. M. A. Nogueira🇧🇷 · M. Reetz🇧🇷 · J. A. Helayël-Neto🇧🇷

   In this contribution, we investigate a supersymmetric effective extension of Axionic Electrody- namics by adopting the superspace/superfield approach. Rather than focusing on UV-complete axion models, our goal is to analyze how supersymmetry modifies the dynamical and propagat- ing sectors of axion electrodynamics at the effective-field-theory level. In terms of component fields, the resulting Lagrangian describes the interactions among the axion, the photon, and their respective supersymmetric partners, the axino, the saxion and the photino. Supersymmetry in- duces new fermionic self-interactions and a non-polynomial interaction involving the axino, the photino, and the saxion. An interesting aspect to be highlighted is the appearance of fermionic bilinear contributions involving the photino to both the permittivity and permeability tensors of the constitutive relations. We also pay special attention to the dispersion relations in both the bosonic and fermionic sectors, and analyze the effective masses of the different particles in the presence of an external magnetic background, which induces supersymmetry breaking. Finally, with the help of numerical methods, we identify a class of axionic and electromagnetic-field configurations with interesting profiles of the magnetic field.

   hep-phhep-th2 citations
9. 09*

   Interpreting the 95 GeV di-photon and di-tau Excesses in the Georgi-Machacek Model

   Qin Chang🇨🇳 · Xiaokang Du🇨🇳 · Pengxuan Zhu🇦🇺

   We revisit the 95~GeV $\gamma \gamma$ and $\tau \tau$ excesses in the Georgi--Machacek model using a combined fit to a single light $CP$-even custodial singlet $H$. Using the one-loop renormalization group-improved effective potential and positive-definiteness conditions for vacuum stability, together with perturbative unitarity, electroweak precision tests, $B$-physics, and Higgs data, we identify a narrow but viable parameter region. In the allowed region ${\mu }_{\gamma \gamma }$ approaches the experimental central value, while ${\mu }_{\tau \tau }$ reaches only $\sim 0.5$ (about $1.4\sigma$ below the CMS central value) and remains within the $2\sigma$ interval - a good description of the di-photon excess but only a partial accommodation of the di-tau excess. The scenario predicts characteristic patterns in the singlet mixing and triplet vacuum expectation values and is highly testable at the HL-LHC and future lepton colliders via precision ${\kappa }_V$ measurements and direct exotic searches.

   hep-ph5 citations
10. 10*

    Using net quark number gain to probe the phases of QCD

    V. Tomas Mari Surkau🇫🇷 · Urko Reinosa🇫🇷

    We discuss an observable that probes the content of a QCD medium at finite temperature and chemical potential, the net quark number gain. It is the response of the thermal bath to a static quark or antiquark probe. While insignificant at high temperatures, it reveals the bath's tendency to form meson-like or baryon-like configurations (depending on the probe and chemical potential) at low temperatures, which would screen the probe's color charge. The net quark number gain also helps explain how a single quark/antiquark can be added to a supposedly confining medium in the first place: the latter provides the missing quarks/antiquarks to form hadron-like states. We sketch the derivation of this general result for temperatures much smaller than the constituent quark masses and discuss possible further applications to study the various features of the QCD phase diagram.

    hep-phhep-thJ.Subatomic Part.Cosmol.(2025)·2 citations
11. 11*

    Impact of Evaporation Barriers on Solar-Captured Dark Matter Distribution and Evaporation Mass

    Xuan Wen🇨🇳

    Evaporation determines the low-mass reach of solar-captured dark matter because that reach is controlled by the small population of particles closest to the escape threshold. We present an orbit-space calculation of the non-thermal distribution of captured dark matter in the presence of an evaporation barrier generated by a smooth in-medium attraction sourced by the solar medium. We show that the barrier not only deepens the effective potential but also reshapes the near-threshold phase-space structure, displacing the equilibrium distribution away from weakly bound, escape-prone trajectories and toward more tightly bound core-crossing orbits, thereby suppressing evaporation and lowering the evaporation mass. Although the bulk population remains near thermal equilibrium, the near-threshold tail, as reflected in the projected velocity spectrum, acquires characteristic non-thermal structure because the barrier deforms the bound orbit space and preferentially retains particles that repeatedly traverse the hot solar core. The near-threshold tail is therefore essential for determining the low-mass reach of solar dark-matter searches in the barrier regime, and our orbit-space treatment captures the relevant physics in a controlled way.

    hep-phNPB(2026)·0 citations
12. 12*

    Universal critical dynamics near the chiral phase transition and the QCD critical point

    Yunxin Ye🇩🇪 · Johannes V. Roth🇩🇪 · Sören Schlichting🇩🇪 · Lorenz von Smekal🇩🇪

    We use a novel real-time formulation of the functional renormalization group (FRG) for dynamical systems with reversible mode couplings to study Model G and H, which are the conjectured dynamic universality classes of the two-flavor chiral phase transition and the QCD critical point, respectively. We compute the dynamic critical exponent in both models in spatial dimensions $2<d<4$. We discuss qualitative commonalities and differences in the non-perturbative RG flow, such as weak scaling relations which hold in either case versus the characteristic strong scaling of Model G which is absent in Model H. For Model G, we also extract a novel dynamic scaling function that describes the universal momentum and temperature dependence of the diffusion coefficient of iso-(axial-)vector charges in the symmetric phase.

    hep-phEPJ Web Conf.(2026)·0 citations
13. 13*

    ${\Lambda }_b\to {\Lambda }^{(\ast )}\nu \bar{\nu }$ and $b\to s$ $B$ decays

    Jong-Phil Lee🇰🇷

    The baryonic $b\to s$ transition ${\Lambda }_b\to {\Lambda }^{(\ast )}\nu \bar{\nu }$ is analyzed. We combine the mesonic counterpart $B^{+}\to K^{+}\nu \bar{\nu }$ and $B^0\to K^{\ast 0}\nu \bar{\nu }$ as well as other observables involving $B$ mesons like $R(K^{(\ast )})$, $\mathrm{Br}(B_s\to {\mu }^{+}{\mu }^{-})$, $\mathrm{Br}(B^{+}\to K^{+}{\mu }^{+}{\mu }^{-})$, and $P_5^{\prime }(B^{+}\to K^{\ast +}{\mu }^{+}{\mu }^{-})$. Using the constraints from mesonic sector, we present predictions for the currently unobserved baryonic decay modes, which is very complementary to mesonic modes for probing new physics. We find that the new physics scale $M_{\mathrm{NP}}$ to be $2.04\mathrm{TeV}\le M_{\mathrm{NP}}\le 11.76\mathrm{TeV}$ (at $1\sigma$) for ordinary heavy new mediators. Our predictions for the branching ratios $\mathrm{Br}({\Lambda }_b\to {\Lambda }^{(\ast )}\nu \bar{\nu })$ are $2.07(1.07)$ times the standard model estimations, which could be verified at future colliders. We also find a sum rule for $\mathrm{Br}({\Lambda }_b\to \Lambda \nu \bar{\nu })$ and $\mathrm{Br}(B\to K^{(\ast )}\nu \bar{\nu })$ that is very similar to that for $b\to c$ semi-leptonic decays.

    hep-ph6 citations
14. 14*

    Machine learning approach to QCD kinetic theory

    Sergio Barrera Cabodevila🇪🇸 · Aleksi Kurkela🇳🇴 · Florian Lindenbauer🇦🇹

    The effective kinetic theory (EKT) of QCD provides a possible picture of various non-equilibrium processes in heavy- and light-ion collisions. While there have been substantial advances in simulating the EKT in simple systems with enhanced symmetry, eventually, event-by-event simulations will be required for a comprehensive phenomenological modeling. As of now, these simulations are prohibitively expensive due to the numerical complexity of the Monte Carlo evaluation of the collision kernels. In this talk, we show how the evaluation of the collision kernels can be performed using neural networks paving the way to full event-by-event simulations.

    hep-phnucl-thEPJ Web Conf.(2026)·1 citation
15. 15*

    Pre-hydrodynamic jet momentum broadening beyond the jet quenching parameter

    Alois Altenburger🇦🇹 · Kirill Boguslavski🇦🇹 · Florian Lindenbauer🇦🇹

    We obtain the collision kernel and related dipole cross section during the initial nonequilibrium stages in heavy-ion collisions. These quantities are a crucial input for jet quenching calculations. We further compute the gluon splitting rates in the AMY formalism resulting from this nonequilibrium kernel. Comparing with thermal and commonly used forms, we find that particularly the gluon splitting rate for parton energies of the order of the hard effective temperature significantly differs from these approximations.

    hep-phnucl-thEPJ Web Conf.(2026)·0 citations
16. 16*

    The Physics of Jet Quenching in Perturbative QCD

    Yacine Mehtar-Tani🇺🇸

    Hard processes in collider experiments typically produce QCD jets, which have long served as precision tests of QCD in the vacuum. More recently, heavy-ion programs at RHIC and the LHC have offered a novel perspective on jets, establishing them as unique probes of strongly interacting matter. Experimental observations, including the suppression of high-$p_T$ hadrons and jets, provide compelling evidence for the formation of a new state of matter and its strong coupling to energetic partons. These advances have motivated new theoretical approaches to jet quenching that go beyond standard perturbative techniques, aiming to elucidate the mechanisms of energy dissipation and thermalization of energetic partons in the quark-gluon plasma. This review highlights recent progress, beginning with a unified description of medium-induced radiation across the Landau-Pomeranchuk-Migdal regime and its role in turbulent gluon cascades. We then examine radiative corrections that renormalize the transport coefficient $\hat{q}$, the mechanism of color decoherence in multi-parton systems, and nonlinear QCD evolution equations for jet energy loss. Finally, we confront this framework with experimental measurements, underscoring the need for precision phenomenology to fully exploit the rich data sets from RHIC and the LHC.

    hep-phnucl-th22 citations
17. 17*

    Unitarity, the optical theorem, and the Pauli exclusion principle

    Peter Matak🇸🇰

    We show that the fermionic exclusion principle in scattering problems manifests itself through constraints implied by unitarity and the optical theorem. Configurations that formally allow identical fermions to appear in the same quantum state at the level of intermediate amplitudes are not pathological. Instead, they turn out to be essential for implementing the Pauli principle in scattering processes. Making this connection explicit resolves an apparent tension between the exclusion principle and unitarity and provides a clarified view of how fermionic statistics manifests itself within the $S$-matrix framework.

    hep-ph0 citations
18. 18*

    Polarized Neutral and Charged Current Semi-Inclusive Deep-Inelastic Scattering at NNLO in QCD

    Leonardo Bonino🇨🇭 · Thomas Gehrmann🇨🇭 · Markus Löchner🇨🇭 · Kay Schönwald🇨🇭 · Giovanni Stagnitto🇮🇹

    The semi-inclusive production of identified hadrons in deeply inelastic lepton scattering on polarized nucleons allows to probe the spin structure of the nucleon target in a more detailed level than through fully inclusive processes. We compute the NNLO QCD corrections to longitudinally polarized semi-inclusive deep inelastic processes mediated by electroweak neutral and charged currents. We present the first calculation of polarized electroweak structure functions in the Larin scheme up to NNLO. Additionally, we reformulate the finite scheme transformation to the $\overline{\text{MS}}$ scheme in a quark flavour basis and identify issues in its assignment to partonic channels in previous calculations. Using our results we perform a detailed phenomenological study of polarized cross sections and of single and double spin asymmetries. We observe large electroweak effects, which need to be included in precision studies of polarized observables.

    hep-phJHEP(2026)·13 citations
19. 19*

    Minimal Majorana neutrino mass models

    Antonio Herrero-Brocal🇪🇸 · Avelino Vicente🇪🇸

    We present an extension of the Casas-Ibarra parametrization that applies to all possible Majorana neutrino mass models. This framework allows us to systematically identify minimal models, defined as those with the smallest number of free parameters. We further analyze the phenomenologically relevant combination of the Yukawa matrix, $y^{†}y$, and show that in certain scenarios it exhibits an unexpected reduction in the number of free parameters, depending on just one real degree of freedom. Finally, the application of our results is illustrated in specific models, which can be tested or falsified due to their definite experimental predictions in heavy neutrino and charged lepton flavor violating decays.

    hep-phJHEP(2026)·3 citations
20. 20*

    Chiral effects and Joule heating in hot and dense matter

    Srimoyee Sen🇺🇸 · Varun Vaidya🇺🇸

    Initial states of dense matter with nonzero electron chiral imbalance could potentially give rise to strong magnetic fields through chiral plasma instability. Previous work indicated that unless chiral chemical potential is as large as the electron vector chemical potential, the growth of magnetic fields due to the instability is washed out by chirality flipping rate enabled by electron mass. We re-examine this claim in a broader range of parameters and find that at higher temperatures the hierarchy is reversed supporting a growing magnetic field for an initial electron chiral chemical potential much smaller than the electron vector chemical potential. Further, we identify a qualitatively new effect relevant for magnetized hot and dense medium where chiral magnetic effect (CME) sourced by density fluctuation acts as a powerful source of Joule heating. Remarkably, even modest chiral chemical potentials (keV) in such environment can deposit energy densities set by the QCD scale in a relatively short time of the order of a few milliseconds or seconds. We speculate how this mechanism makes CME-driven Joule heating a potentially critical ingredient in the dynamics of turbulent density fluctuation of supernovae and neutron star mergers.

    hep-phastro-ph.HEnucl-thPRD(2026)·3 citations
21. 21*

    Pre-equilibrium charm quark dynamics and their impact on D-Meson observables

    Manu Kurian🇮🇳 · Mayank Singh🇺🇸 · Charles Gale🇨🇦 · Sangyong Jeon🇨🇦 · Björn Schenke🇺🇸

    We study the impact of pre-equilibrium evolution on the charm quark $R_{AA}$ and $v_2$ in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV. We observe that there is significant diffusion in the pre-equilibrium evolution, but there is no measurable effect on the final state observables.

    ↳ nucl-thhep-phEPJ Web Conf.(2026)·0 citations
22. 22*

    Updated observational constraints on $\varphi$CDM dynamical dark energy cosmological models

    Chan-Gyung Park🇰🇷 · Bharat Ratra🇺🇸

    We present updated observational constraints on the spatially flat $\varphi$CDM model, where dark energy is described by a minimally coupled scalar field $\varphi$ with an inverse power-law potential $V=V_0{\varphi }^{-\alpha }$. Using Planck 2018 CMB temperature, polarization (P18), and lensing power spectra (lensing), along with a compilation of non-CMB data including baryon acoustic oscillation, type Ia supernova, Hubble parameter, and growth rate measurements, we constrain $\varphi$CDM and $\varphi$CDM+$A_L$ models where $A_L$ is the CMB lensing consistency parameter. The scalar field parameter $\alpha$, which governs dark energy dynamics, is more tightly constrained by non-CMB data than by CMB data alone. For the full dataset, we obtain $\alpha =0.055\pm 0.041$ in the $\varphi$CDM model and $\alpha =0.095\pm 0.056$ in the $\varphi$CDM+$A_L$ model, mildly favoring evolving dark energy over a cosmological constant by $1.3\sigma$ and $1.7\sigma$. The Hubble constant is $H_0=67.55_{-0.46}^{+0.53}$ km s${}^{-1}$ Mpc${}^{-1}$ in the $\varphi$CDM model, consistent with median statistics and some local determinations, but in tension with other local determinations. The constraints for matter density and clustering amplitude (${\Omega }_m=0.3096\pm 0.0055$, ${\sigma }_8=0.8013_{-0.0067}^{+0.0077}$) of the flat $\varphi$CDM model statistically agree with $\Lambda$CDM model values. Allowing $A_L$ to vary reduces tensions between CMB and non-CMB data, although we find $A_L=1.105\pm 0.037$, $2.8\sigma$ higher than unity, consistent with the excess smoothing seen in Planck data. Model comparison using AIC and DIC indicates that the $\varphi$CDM model provides a fit comparable to $\Lambda$CDM, with the $\varphi$CDM+$A_L$ slightly preferred. Overall, while the $\Lambda$CDM model remains an excellent fit, current data leave open the possibility of mildly evolving quintessence-like dynamical dark energy.

    ↳ astro-ph.COgr-qchep-phhep-thInt.J.Mod.Phys.D(2026)·25 citations
23. 23*

    Bulk viscosity from neutron decays to dark baryons in neutron star matter

    Steven P. Harris🇺🇸 · C.J. Horowitz🇺🇸

    The existence of a dark baryon that mixes with the neutron leads to the possibility of neutron decay into a dark sector. Such dark decays have been studied as possibly relevant for the neutron decay anomaly and for their potential impacts on neutron stars. The most popular formulation is a dark sector consisting of a dark baryon $\chi$ and a dark scalar $\varphi$, where a neutron in vacuum decays 1% or less of the time via the channel $n\to \chi +\varphi$. In this work, we consider the effect of this additional neutron decay channel on transport in neutrons star mergers. We find that the neutron dark decay rate in medium is quite slow, and thus the dark baryons modify the dense matter equation of state in a way that decreases the Urca bulk viscosity by, at most, a factor of 2-3. However, if the neutron dark decay was to occur more rapidly, then the bulk viscosity at merger temperatures of tens of MeV would be strongly enhanced, potentially rapidly damping oscillations in merger environments and therefore providing a signature of slowly equilibrating matter in the merger.

    ↳ astro-ph.HEhep-phnucl-thPRD(2026)·5 citations
24. 24*

    Perturbation theory, irrep truncations, and state preparation methods for quantum simulations of SU(3) lattice gauge theory

    Praveen Balaji🇺🇸 · Cianan Conefrey-Shinozaki🇺🇸 · Patrick Draper🇺🇸 · Jason K. Elhaderi🇺🇸 · Drishti Gupta🇺🇸 · Luis Hidalgo🇺🇸 · Andrew Lytle🇺🇸

    We study methods for efficient preparation of approximate ground states of $SU(3)$ lattice gauge theory on quantum hardware. Working in a variant of the electric basis, we introduce a refinement of the irrep truncation based on the energy density of site singlets, which provides a finer gradation of simulation complexity. Using strong-coupling perturbation theory as a guide, we develop simple ansatz circuits for ground state preparation and test them via classical simulation on small lattices, including the $2\times 2$ plaquette lattice in $d=2$ and the cube in $d=3$. We contrast state fidelities and resource requirements of variational methods against adiabatic state preparation and introduce a method that hybridizes the two approaches. Finally, we report on the public release of \texttt{ymcirc} -- a package of tools for building $SU(3)$ circuits and processing measurements -- and \texttt{pyclebsch}, a package for efficiently computing $SU(N)$ Clebsch-Gordan coefficients.

    ↳ hep-lathep-phquant-phPRD(2026)·18 citations
25. 25*

    Study of chaos and scrambling in hairy AdS Soliton

    Adrita Chakraborty🇵🇱 · Balbeer Singh🇮🇳

    In this work, we perform a comprehensive study of the classical and quantum chaos in a candidate five-dimensional hairy AdS soliton. It is a horizonless geometry holographically dual to a confining field theory with finite scalar potential. We probe classical chaos by using particle geodesics and closed classical string. While the former shows no signature of chaos, the latter provides chaotic dynamics of the string using the Lyapunov exponent and the evolution of the Poincaré section. We perform an independent spectral analysis using the tools of the random matrix theory (RMT), namely the level space distributions and the Dyson-Mehta(DM) ${\Delta }_3$-statistics. We observe a clear transition from the low energy Wigner-Gaussian Orthogonal Ensemble (GOE) distribution to the high energy Poisson distribution. This signifies a flow from quantum chaos in the infrared to integrability in the ultraviolet. We quantitatively characterize the inherent quantum scrambling in the dual theory by computing the butterfly velocity, the rate of spatial spread of the information scrambling, inside the bulk. We undergo two independent holographic methods -- entanglement wedge reconstruction and derivation of out-of-time-ordered correlators via shockwave analysis. In these methods, we heuristically consider the region near the soliton tip to provide the infrared physics of scrambling in analogy with the near-horizon region of a black hole. We find that the hair parameter controls various scrambling properties. Finally, we make comments on the interplay between insulator/superconductor phase transition in hairy soliton geometry and dynamical transition from integrability to chaos as both of these are affected by the presence of the hair parameter.

    ↳ hep-thhep-phJHEP(2026)·2 citations
26. 26*

    Cosmological constraints on nonphantom dynamical dark energy with DESI Data Release 2 Baryon Acoustic Oscillations: A 3$\sigma$+ lensing anomaly

    Shouvik Roy Choudhury🇹🇼 · Teppei Okumura🇹🇼 · Keiichi Umetsu🇹🇼

    We consider a 12-parameter cosmological model with non-phantom dynamical dark energy (NPDDE), where non-phantom implies that the equation of state (EoS) of dark energy (DE), $w(z)\ge -1$ for all redshifts $z$. Thus, the DE EoS covers the parameter space corresponding to the popular single scalar-field dark energy models, i.e., Quintessence. The cosmological model comprises 6 parameters of the $\Lambda$-Cold Dark Matter ($\Lambda$CDM) model, and additionally the dynamical DE EoS parameters ($w_0$, $w_a$), the scaling of the lensing amplitude ($A_{\mathrm{lens}}$), sum of the neutrino masses ($\sum m_{\nu }$), the effective number of non-photon relativistic degrees of freedom ($N_{\mathrm{eff}}$), and the running of the scalar spectral index (${\alpha }_s$). We derive constraints on the parameters by combining the latest Dark Energy Spectroscopic Instrument (DESI) Data Release (DR) 2 Baryon Acoustic Oscillation (BAO) measurements with cosmic microwave background (CMB) power spectra from Planck Public Release (PR) 4, CMB lensing data from Planck PR4 and Atacama Cosmology Telescope (ACT) DR6, uncalibrated Type Ia supernovae (SNe) data from the Pantheon+ and Dark Energy Survey (DES) Year 5 (DESY5) samples, and Weak Lensing (WL) data from DES Year 1. Our major finding is that with CMB+BAO+WL and CMB+BAO+SNe+WL, we find 3$\sigma$+ evidence for $A_{\mathrm{lens}}>1$, indicating a higher than expected CMB lensing amplitude relative to the NPDDE prediction of unity. This implies that for cosmology to accommodate realistic quintessence-like dark energy models (as opposed to unrealistic phantom DE), one would also need to explain a relatively significant presence of the lensing anomaly.

    ↳ astro-ph.COhep-phApJL·53 citations
27. 27*

    Multi-strangeness matter from ab initio calculations

    Hui Tong🇩🇪 · Serdar Elhatisari🇹🇷 · Ulf-G. Meißner🇩🇪 · Zhengxue Ren🇨🇳

    Hypernuclei and hypernuclear matter connect nuclear structure in the strangeness sector with the astrophysics of neutron stars, where hyperons are expected to emerge at high densities and affect key astrophysical observables. We present the first {\em ab initio} calculations that simultaneously describe single- and double-$\Lambda$ hypernuclei from the light to medium-mass range, the equation of state for $\beta$-stable hypernuclear matter, and neutron star properties. Despite the formidable complexity of quantum Monte Carlo~(QMC) simulations with multiple baryonic degrees of freedom, by combining nuclear lattice effective field theory with a newly developed auxiliary-field QMC algorithm we achieve the first sign-problem free {\em ab initio} QMC simulations of hypernuclear systems containing an arbitrary number of neutrons, protons, and $\Lambda$ hyperons, including all relevant two- and three-body interactions. This eliminates reliance on the symmetry-energy approximation, long used to interpolate between symmetric nuclear matter and pure neutron matter. Our unified calculations reproduce hyperon separation energies, yield a neutron star maximum mass consistent with observations, predict tidal deformabilities compatible with gravitational-wave measurements, and give a trace anomaly in line with Bayesian constraints. By bridging the physics of finite hypernuclei and infinite hypernuclear matter within a single {\em ab initio} framework, this work establishes a direct microscopic link between hypernuclear structure, dense matter composition, and the astrophysical properties of neutron stars.

    ↳ nucl-thastro-ph.HEastro-ph.SRhep-lat+18 citations
28. 28*

    Event Tokenization and Masked-Token Prediction for Anomaly Detection at the Large Hadron Collider

    Ambre Visive (1 and 2)🇳🇱 · Polina Moskvitina (3 and 2)🇳🇱 · Clara Nellist (1 and 2)🇳🇱 · Roberto Ruiz de Austri (4)🇪🇸 · Sascha Caron (3 and 2) ((1) Institute of Physics, University of Amsterdam, Amsterdam, The Netherlands, (2) Nikhef, Dutch National Institute for Subatomic Physics, Amsterdam, The Netherlands, (3) High Energy Physics, Radboud University, Nijmegen, The Netherlands, (4) Instituto de Física Corpuscular, IFIC-UV/CSIC, Paterna, Spain)🇳🇱

    We propose a novel use of Large Language Models (LLMs) as unsupervised anomaly detectors in particle physics. Using lightweight LLM-like networks with encoder-based architectures trained to reconstruct background events via masked-token prediction, our method identifies anomalies through deviations in reconstruction performance, without prior knowledge of signal characteristics. Applied to searches for simultaneous four-top-quark production, this token-based approach shows competitive performance against established unsupervised methods and effectively captures subtle discrepancies in collider data, suggesting a promising direction for model-independent searches for new physics.

    ↳ hep-exhep-ph2 citations
29. 29*

    Two-component diffuse Galactic gamma-ray emission revealed with Fermi-LAT

    Qi-Ling Chen🇨🇳 · Qiang Yuan🇨🇳 · Yi-Qing Guo🇨🇳 · Ming-Ming Kang🇨🇳 · Chao-Wen Yang🇨🇳

    The enigma of cosmic ray origin and propagation stands as a key question in particle astrophysics. The precise spatial and spectral measurements of diffuse Galactic gamma-ray emission provide new avenues for unraveling this mystery. Based on 16 years of Fermi-LAT observations, we find that the diffuse gamma-ray spectral shapes are nearly identical for low energies (below a few GeV) but show significant dispersion at high energies (above a few GeV) across the Galactic disk. We further show that the diffuse emission can be decomposed into two components, a universal spectral component dominating at low energies which is consistent with the expectation from interactions of background cosmic rays and the interstellar matter, and a spatially variant component dominating at high energies which is likely due to local accelerators. These findings suggest that there is dual-origin of the Galactic diffuse emission, including the ``cosmic ray sea'' from efficient propagation of particles and the ``cosmic ray islands'' from inefficient propagation of particles, and thus shed new light on the understanding of the propagation models of Galactic cosmic rays.

    ↳ astro-ph.HEhep-ph0 citations
30. 30*

    Initial spin fluctuations in heavy-ion collisions and where to find them

    Giuliano Giacalone🇨🇭 · Enrico Speranza🇮🇹

    Collective spin phenomena in the final states of heavy-ion collisions are typically understood to originate from vorticity and shear in the quark-gluon plasma. Here, we ask whether spin could already be present in the initial condition of the collisions. In particular, we argue that if a spin density exists at the beginning of the QGP expansion, it should experience event-by-event fluctuations due to the finite number of participant nucleons. In this contribution, we propose a simple model of fluctuating spin initial conditions for event-by-event spin hydrodynamics based on the Glauber Monte Carlo paradigm. We postulate that, if the net spin of the events is conserved from the initial to the final state, then initial state fluctuations of spin should manifest in specific spin correlations of $\Lambda$ hyperons. Within our picture, we predict that this signal is much larger in central O+O collisions than in central Pb+Pb collisions.

    ↳ nucl-thhep-exhep-phnucl-exEPJ Web Conf.(2026)·0 citations
31. 31*

    Quantum fermion emission from excited kinks

    Sergio Alameda-Calvo🇪🇸 · Jose J. Blanco-Pillado🇪🇸 · Alberto García Martín-Caro🇪🇸

    The amplitude of an excited shape mode in a kink is expected to decay with a well-known power law via scalar radiation emission due to the nonlinear self-coupling of the scalar field. In this work we propose an alternative decay mechanism via pair production of fermions in a simple extension of the ${\varphi }^4$ model in which the scalar field is coupled to a (quantum) fermionic field through a Yukawa-like interaction term. We study the power emitted through fermions as a function of the coupling constant in the semi-classical limit (without backreaction) and compare it to the case of purely scalar radiation emission.

    ↳ hep-thhep-phJHEP(2026)·0 citations
32. 32*

    Dark forces suppress structure growth

    Marco Costa🇨🇦 · Cyril Creque-Sarbinowski🇺🇸 · Olivier Simon🇺🇸 · Zachary J. Weiner🇨🇦

    No experimental test precludes the possibility that the dark matter experiences forces beyond general relativity---in fact, a variety of cosmic microwave background observations suggest greater late-time structure than predicted in the standard $\Lambda$ cold dark matter model. We show that minimal models of scalar-mediated forces between dark matter particles do not enhance the growth of unbiased tracers of structure: weak lensing observables depend on the total density perturbation, for which the enhanced growth of the density contrast in the matter era is cancelled by the more rapid dilution of the background dark matter density. Moreover, the same background-level effects imply that scenarios compatible with CMB temperature and polarization anisotropies in fact suppress structure growth, as fixing the distance to last scattering requires a substantially increased density of dark energy. Though massive mediators undo these effects upon oscillating, they suppress structure even further because their gravitational impact as nonclustering subcomponents of matter outweighs the enhanced clustering strength of dark matter. We support these findings with analytic insight that clarifies the physical impact of dark forces and explains how primary CMB measurements calibrate the model's predictions for low-redshift observables. We discuss implications for neutrino mass limits and other cosmological anomalies, and we also consider how nonminimal extensions of the model might be engineered to enhance structure.

    ↳ astro-ph.COhep-phJCAP(2026)·16 citations
33. 33*

    Constraints on the Thompson optical depth to the CMB from the Lyman-$\alpha$ forest

    Olga Garcia-Gallego🇬🇧 · Vid Iršič🇬🇧 · Martin G. Haehnelt🇬🇧 · James S. Bolton🇬🇧

    We present the first constraints on the electron optical depth to reionization, ${\tau }_{\mathrm{e}}$, from the Lyman-$\alpha$ forest alone for physically motivated reionization models that match the reionization's end-point, $z_{\mathrm{end}}$, required by the same astrophysical probe, and for symmetric reionization models with fixed duration, $\Delta z$, commonly adopted in CMB reionization analyses. Compared to traditional estimates from the latter, the Lyman-$\alpha$ forest traces the ionization state of the IGM through its coupling with the thermal state. We find an explicit mapping between the two solving the chemistry and temperature evolution equations for hydrogen and helium. Our results yield ${\tau }_{\mathrm{e}}$=$0.042_{-0.02}^{+0.047}$ (95% C.L) and ${\tau }_{\mathrm{e}}$=$0.042_{-0.015}^{+0.024}$ for reionization models with $z_{\mathrm{end}}$ and $\Delta z$-fixed, respectively, disfavoring a high ${\tau }_{\mathrm{e}}$=0.09 by 2.57$\sigma$ and 4.31$\sigma$. With mock Lyman-$\alpha$ forest data that mimics the precision of future larger quasar sample datasets, we would potentially obtain tighter ${\tau }_{\mathrm{e}}$ constraints and exclude such a high ${\tau }_{\mathrm{e}}$ with a higher significance, paving the way for novel constraints on the epoch of reionization from a large-scale structure probe independent of the CMB.

    ↳ astro-ph.COhep-phhep-thPRResearch(2026)·13 citations
34. 34*

    Geodesics in Quantum Gravity

    Benjamin Koch🇦🇹 · Ali Riahinia🇦🇹 · Angel Rincon🇨🇿

    We investigate the motion of test particles in quantum-gravitational backgrounds by introducing the concept of q--desics, quantum-corrected analogs of classical geodesics. Unlike standard approaches that rely solely on the expectation value of the spacetime metric, our formulation is based on the expectation value of quantum operators, such as the the affine connection-operator. This allows us to capture richer geometric information. We derive the q--desic equation using both Lagrangian and Hamiltonian methods and apply it to spherically symmetric static backgrounds obtained from canonical quantum gravity. Exemplary results include, light-like radial motion and circular motion with quantum gravitational corrections far above the Planck scale. This framework provides a refined description of motion in quantum spacetimes and opens new directions for probing the interface between quantum gravity and classical general relativity.

    ↳ gr-qchep-phhep-thPRD(2025)·2 citations
35. 35*

    QCD in strong magnetic fields: fluctuations of conserved charges and EoS

    Heng-Tong Ding🇨🇳 · Jin-Biao Gu🇨🇳 · Arpith Kumar🇨🇳 · Sheng-Tai Li🇨🇳

    Strong magnetic fields can profoundly affect the equilibrium properties, characterized by the equation of state and bulk thermodynamics of strongly interacting matter. Although such fields are expected in off-central heavy-ion collisions, directly measuring their experimental imprints remains extremely challenging. To address this, we propose the baryon-electric charge correlations ${\chi }_{11}^{\mathrm{BQ}}$ and the chemical potential ratio ${\mu }_{\mathrm{Q}}/{\mu }_{\mathrm{B}}$ as magnetic-field-sensitive probes, based on (2+1)-flavor QCD lattice simulations at physical pion masses. Along the transition line, ${\chi }_{11}^{\mathrm{BQ}}$ and $({\mu }_{\mathrm{Q}}/{\mu }_{\mathrm{B}}{)}_{\mathrm{LO}}$ in Pb-Pb collisions increase by factors of 2.1 and 2.4 at $eB\simeq 8M_{\pi }^2$, respectively. To bridge theoretical predictions and experimental observations, we construct HRG-based proxies and apply systematic kinematic cuts to emulate STAR and ALICE detector acceptances. Furthermore, we extend this investigation to the QCD equation of state, and examine the leading-order thermodynamic coefficients for strangeness-neutral scenarios up to $eB\simeq 0.8{\mathrm{GeV}}^2\sim 45m_{\pi }^2$, revealing intriguing non-monotonic structures.

    ↳ hep-lathep-phnucl-exnucl-thJ.Subatomic Part.Cosmol.(2026)·4 citations

* 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.