Fri·Jul 11, 2025Friday·July 11, 2025

1. 01*

   Quantum simulation of scattering amplitudes and interferences in perturbative QCD

   Herschel A. Chawdhry🇺🇸 · Mathieu Pellen🇩🇪 · Simon Williams🇬🇧

   A flagship application of quantum computers is the simulation of other quantum systems, including quantum field theories. In this article, we show how quantum computers can be employed to naturally calculate Feynman diagrams and their interferences in Quantum Chromodynamics (QCD). We simulate the colour parts of the interactions directly on the quantum computer, while the kinematic parts are for now pre-computed classically. For processes where some of the external particles are identical, we find the first hints of a potential quantum advantage. We validate our techniques using simulated quantum computers. Furthermore, for toy examples we also demonstrate our algorithms on a 56-qubit trapped-ion quantum computer. The work constitutes a further key step towards a full quantum simulation of generic perturbative QCD processes.

   hep-phhep-thquant-phEPJC(2026)·8 citations
2. 02*

   Chiral Cherenkov radiation in the presence of a time-dependent chiral chemical potential

   Kirill Tuchin🇺🇸

   The photon production process $f\to f+\gamma$ in the presence of a time-dependent chiral chemical potential ${\mu }_5$ is studied. The validity of the adiabatic approximation is demonstrated in the ultra-relativistic limit. Analytical expressions for the photon spectrum are derived for two models of the chiral magnetic conductivity $b_0\propto {\mu }_5$: (i) $b_0(t)=A_1+B_1\tanh (t/\tau )$ and (ii) $b_0(t)=A_2(t/\tau )/(1+t^2/{\tau }^2)$. It is known that for constant $b_0$, photon emission may exhibit a resonance for one photon polarization depending on the sign of $b_0$. It is shown that in model (i), up to two resonances may occur, depending on the sign of the asymptotic values $b_0(\infty )$ and $b_0(-\infty )$. No resonances are observed in model (ii). Numerical calculations are performed using parameters relevant to quark-gluon plasma, and the universality of the results is discussed.

   hep-phnucl-thPRC(2025)·4 citations
3. 03*

   Thermodynamic Analysis of Transverse Momentum Spectra in Pb-Pb Collisions at 2.76 TeV: Centrality Dependence of Temperature, Freezeout Parameters and Non-Extensitivity

   M. Waqas🇨🇳 · Hassan Ali Khan🇨🇳 · Wolfgang Bietenholz🇲🇽 · Muhammad Ajaz🇵🇰 · Jihane Ben Slimane🇸🇦 · Haifa I. Alrebdi🇸🇦 · A. Haj Ismail🇦🇪

   We study properties of Pb-Pb collisions at 2.76 TeV in mid-rapidity, $|y|<0.5$, based on data by the ALICE Collaboration. In particular, we examine the transverse momentum ($p_T$) spectra of positively charged (identified) hadrons, ${\pi }^{+}$, $K^{+}$ and $p$, generated in various centrality intervals. We perform individual fits using the thermodynamically consistent Tsallis distribution to extract the following quantities: the non-extensitivity parameter, $q$, the effective temperature, $T_{\mathrm{eff}}$, the kinetic freezeout volume, $V$, the mean transverse flow velocity, ${\beta }_T$, the mean kinetic freezeout temperature, $⟨T_0⟩$, the thermal temperature, $T_{\mathrm{th}}$, and the parameter $\zeta$, which characterizes the fluctuating number of generated particles. From peripheral to central collision, and from lower to higher charged particle multiplicity per pseudorapidity unit, $⟨d{N}_{\mathrm{ch}}/d\eta ⟩$, all these quantities are observed to increase, with the exception of $q$, which has the opposite behavior. The parameters $T_{\mathrm{eff}}$, $q$, and $V$ depend on the hadron mass in a way that supports the scenarios of volume differential freezeout and multiple kinetic freezeout. Furthermore, we extracted $⟨T_{\mathrm{eff}}⟩$ and $⟨q⟩$ for different collisions and energies at LHC and RHIC, and compare their dependencies on $⟨d{N}_{\mathrm{ch}}/d\eta ⟩$ and $⟨N_{\mathrm{part}}⟩$.

   hep-phnucl-thEPJA(2025)·1 citation
4. 04*

   LIQUIDating the Gallium Anomaly

   Garv Chauhan🇺🇸 · Patrick Huber🇺🇸

   The gallium anomaly has a global significance of greater than $5\sigma$. Most viable BSM solutions quickly run into strong tensions with reactor and solar neutrino data. We propose to use indium (${}^{115}\text{In}$) as a target as it offers a low threshold and reasonably high cross section. The neutrino-indium charged current cross section can be calibrated using the well-constrained solar ${}^7\text{Be}$ neutrino flux that lies very close in energy to the ${}^{51}\text{Cr}$ neutrino lines. The triple coincidence provided by ${}^{115}\text{In}$ neutrino capture can be fully exploited by an opaque scintillation detector that also provides energy and position information. We show that a $100$ ton indium target combined with 2 source runs of a $3.4$ MCi ${}^{51}\text{Cr}$ source can probe the complete parameter space of the gallium anomaly, both in the context of a vanilla sterile neutrino as well as more involved BSM scenarios.

   hep-ph4 citations
5. 05*

   A comparative study of physics capabilities of a liquid argon and a water based liquid scintillator at DUNE

   Nishat Fiza🇰🇷 · Suhyeon Kim🇰🇷 · Emar Masaku🇰🇷 · Mehedi Masud🇰🇷 · Hokyeong Nam🇰🇷 · Juseong Park🇰🇷 · Yujin Park🇰🇷 · Kim Siyeon🇰🇷

   We present a comprehensive comparison of the physics sensitivities of a Liquid Argon Time Projection Chamber (LArTPC) and a Water-based Liquid Scintillator (WbLS) detector, considering their potential deployment as the fourth far detector module in the DUNE facility. Using GLoBES-based simulations, we evaluate their performance in measuring standard neutrino oscillation parameters (${\theta }_{23},{\delta }_{13}$ and $\Delta m_{31}^2$), both in standard 3-neutrino case, as well as in presence of new physics scenarios involving light sterile neutrinos and neutral-current non-standard interactions (NC NSI). Our findings show that THEIA (a WbLS-based detector) significantly outperforms LArTPC in resolving the CP phase ${\delta }_{13}$,- especially near maximal CP violation, and in lifting the octant degeneracy of ${\theta }_{23}$ due to its superior energy resolution and ability to clearly identify the second oscillation maximum. Furthermore, THEIA offers competitive reconstruction precision even with relatively moderate energy resolutions ($7-10\%/\sqrt{E}$) and demonstrates enhanced robustness under new physics scenarios. These results support the physics-driven case for a hybrid DUNE configuration utilizing both LArTPC and WbLS technologies for optimized sensitivity across the full spectrum of neutrino oscillation and physics beyond the standard model.

   hep-phhep-ex1 citation
6. 06*

   Probing Fundamental Constant Oscillation in the Galactic Center with S-Star Spectroscopy

   Zhaoyu Bai🇮🇱 · Vitor Cardoso🇩🇰 · Yifan Chen🇩🇰 · Tuan Do🇺🇸 · Aurélien Hees🇫🇷 · Huangyu Xiao🇺🇸 · Xiao Xue🇪🇸

   Astrophysical spectroscopy provides a powerful probe of spacetime variations of fundamental constants, as atomic and ionic emission and absorption lines depend sensitively on the fine-structure constant. In particular, coherent temporal oscillations induced by an ultralight scalar background produce characteristic, time-resolved signatures that can be robustly disentangled from intrinsic variability. In the Galactic Center, such scalar backgrounds can be substantially enhanced, either through the formation of dense scalar clouds powered by black hole rotational energy extraction or as ultralight scalar dark matter forming a soliton-like core. These scalar configurations generically induce oscillations of the fine-structure constant, with periods set by the scalar mass and spatial profiles determined by the scalar wavefunction and its coupling to the electromagnetic sector. We show that precise, time-resolved spectroscopy of S-stars orbiting the supermassive black hole Sgr A${}^{\ast }$ provides a sensitive test of these effects, enabling constraints on quadratic scalar-photon couplings in the exceptionally high boson-density environment of the Galactic Center.

   hep-phastro-ph.HEgr-qcJCAP(2026)·16 citations
7. 07*

   The Electromagnetic Form Factors of Pseudoscalar Mesons within the Light-Front Quark Model

   Shuai Xu🇨🇳 · Xiao-Nan Li🇨🇳 · Xing-Gang Wu🇨🇳

   In this paper, we investigate the electromagnetic form factors (EMFFs) and charge radii of pseudoscalar mesons within the light-front quark model (LFQM). Using parameters derived from the confinement of mesonic decay constants, we obtain numerical results, which indicate the following: (i) The EMFFs of charged and neutral mesons exhibit significant differences in their endpoint behaviors but show similar asymptotic behavior in the high momentum transfer ($Q^2$) regions. For the EMFFs of light mesons such as $\pi$ and $K^{+}$, our results are in excellent agreement with experimental data in the low $Q^2$ regions. For the charge radii of mesons, our results also show rough consistency with predictions from other approaches. (ii) For charged mesons, the peak values of $Q^2{F}_P(Q^2)$ are approximately proportional to the mass difference $\Delta m$ between their constituent quarks. Moreover, the mean square radii ${⟨r^2⟩}_P$ of charged mesons decrease with increasing meson mass and decreasing $\Delta m$. For neutral mesons, their charge radii are primarily determined by the electric charge of the heavy quark. These results indicate that quark mass asymmetry significantly influences the behavior of the EMFFs and charge radii of mesons. Experimental data to test these predictions would thus be of great interest.

   hep-phSCPMA(2026)·6 citations
8. 08*

   Learning Pole Structures of Hadronic States using Predictive Uncertainty Estimation

   Felix Frohnert🇳🇱 · Denny Lane B. Sombillo🇵🇭 · Evert van Nieuwenburg🇳🇱 · Patrick Emonts🇩🇪

   Matching theoretical predictions to experimental data remains a central challenge in hadron spectroscopy. In particular, the identification of new hadronic states is difficult, as exotic signals near threshold can arise from a variety of physical mechanisms. A key diagnostic in this context is the pole structure of the scattering amplitude, but different configurations can produce similar signatures. The mapping between pole configurations and line shapes is especially ambiguous near the mass threshold, where analytic control is limited. In this work, we introduce an uncertainty-aware machine learning approach for classifying pole structures in $S$-matrix elements. Our method is based on an ensemble of classifier chains that provide both epistemic and aleatoric uncertainty estimates. We apply a rejection criterion based on predictive uncertainty, achieving a validation accuracy of nearly $95\%$ while discarding only a small fraction of high-uncertainty predictions. Trained on synthetic data with known pole structures, the model generalizes to previously unseen experimental data, including enhancements associated with the $P_{c\bar{c}}(4312{)}^{+}$ state observed by LHCb. In this, we infer a four-pole structure, representing the presence of a genuine compact pentaquark in the presence of a higher channel virtual state pole with non-vanishing width. While evaluated on this particular state, our framework is broadly applicable to other candidate hadronic states and offers a scalable tool for pole structure inference in scattering amplitudes.

   hep-phcs.AIcs.LGhep-exPRD(2026)·3 citations
9. 09*

   QCD-inspired description of multiplicity distributions in jets

   Yu.L. Dokshitzer🇱🇻 · B.R. Webber🇬🇧

   We suggest a universal QCD-motivated expression for the Polyakov-KNO multiplicity distributions of hadrons in jets and compare it with data from $e^{+}{e}^{-}$ annihilation experiments. The moments and overall shape of the distributions in full events and quark and gluon jets, over a range of energies, are described with reasonable quantitative precision. In particular, the scaling violation predicted by QCD is seen clearly in the moments and high-multiplicity fluctuations.

   hep-phJHEP(2025)·9 citations
10. 10*

    New Isobar Models for $K^{+}\Lambda$ Electroproduction

    Jovan Alfian Djaja🇮🇩 · Terry Mart🇮🇩

    The electroproduction of kaon on proton has been studied using two covariant isobar models. The models incorporate propagators and vertex factors developed in our previous works. In total, the current study includes 26 nucleon resonances and 20 hyperon resonances, with spins up to 13/2. In the electromagnetic vertices, we consider two alternative electromagnetic form factors alongside the commonly used dipole model. The unknown parameters in the models, such as longitudinal coupling constants and form factor cutoffs, are determined by fitting the calculated observables to nearly 2000 experimental data points. The resulting models demonstrate satisfactory consistency with the available experimental data.

    hep-phnucl-thJ.Phys.Conf.Ser.(2025)·1 citation
11. 11*

    Entropy production at electroweak bubble walls from scalar field fluctuations

    M. Eriksson🇨🇭 · M. Laine🇨🇭

    The real-time dynamics of an electroweak phase transition involves large time and distance scales, the domain of hydrodynamics. However, the matching conditions of ideal hydrodynamics across a bubble wall do not fix the fluid profile completely, with the remaining degree of freedom parametrizable through entropy production. Within a framework of Langevin dynamics, viewed as an effective description valid between the hydrodynamic ($k\sim g_{}^{4}T/{\pi }_{}^3$) and soft momentum scales ($k\sim gT$), we determine the entropy production originating from scalar field fluctuations. The entropy discontinuity is shown to remain non-vanishing when the friction coefficient is sent to zero, in apparent violation of the ``local thermal equilibrium'' (LTE) framework. To confirm the finding, we identify its origin within Boltzmann equations, as being part of the $1\to 1$ force associated with the ``ballistic'' regime. The result implies that LTE-based upper bounds on the wall velocity cannot be saturated.

    hep-phJCAP(2025)·8 citations
12. 12*

    Constraints on axionlike particles from 16.5 years of Fermi-LAT data and prospects for VLAST

    Zhi-Qi Guo🇨🇳 · Yue-Lin Sming Tsai🇨🇳 · Lei Wu🇨🇳 · Zi-Qing Xia🇨🇳

    Axionlike particles (ALPs), hypothetical particles beyond the Standard Model, are considered as promising dark matter candidates. ALPs can convert into photons and vice versa in a magnetic field via the Primakoff effect, potentially generating detectable oscillation in $\gamma$-ray spectra. This study analyzes 16.5 years of data from the Fermi Large Area Telescope (Fermi-LAT) on NGC 1275, the brightest galaxy in the Perseus cluster, to constrain the ALP parameter space. Our results improve the previous 95\% exclusion limits of the photon-ALP coupling $g_{a\gamma }$ by a factor of 2 in the ALP mass range of $4\times 10^{-10}\mathrm{eV}\lesssim m_a\lesssim 5\times 10^{-9}\mathrm{eV}$. Moreover, we investigate the projected sensitivity of the future Very Large Area $\gamma$-ray Space Telescope (VLAST) on searching for ALPs. We find that (i) the expected sensitivity on the ALP-photon coupling can be stronger than that from the upcoming International Axion Observatory (IAXO) in the ALP mass range of $2\times 10^{-11}\mathrm{eV}\lesssim m_a\lesssim 1\times 10^{-7}\mathrm{eV}$, with the best sensitivity of $g_{a\gamma }\sim 7\times 10^{-13}\mathrm{Ge}{\mathrm{V}}^{-1}$ at $m_a\sim 2\times 10^{-10}\mathrm{eV}$; (ii) VLAST can extend the sensitivity of the ALP masses below $5\times 10^{-12}\mathrm{eV}$, where the ALP-photon coupling $g_{a\gamma }\gtrsim 1.5\times 10^{-11}\mathrm{Ge}{\mathrm{V}}^{-1}$ will be excluded; (iii) the entire parameter space of ALP accounting for TeV transparency can be fully tested. These results demonstrate that VLAST will offer an excellent opportunity for ALPs searches.

    hep-phastro-ph.HEPRD(2025)·4 citations
13. 13*

    Femtoscopy of $DN$ and $\bar{D}N$ systems

    Mikel F. Barbat🇪🇸 · Juan M. Torres-Rincon🇪🇸 · Angels Ramos🇪🇸 · Laura Tolos🇪🇸

    The capability of the ALICE@LHC and STAR@RHIC experiments to reconstruct $D$ mesons has enabled femtoscopic correlation measurements of open-charm mesons in both small and large systems. In this work, we present a theoretical calculation of the correlation functions of $D$ and $\bar{D}$ mesons with nucleons, based on the Koonin-Pratt formalism. We employ an effective Lagrangian to model the interaction between charmed mesons and baryons and apply the TROY formalism to obtain the off-shell $T$-matrix in coupled channels, incorporating the effect of the Coulomb interaction when the pair involves two charged particles. The resulting full coupled-channel wave function is inserted into the Koonin-Pratt equation with channel weights derived from a thermal model. Additionally, we compute the correlation functions using the Lednický-Lyuboshitz approximation with low-energy scattering parameters extracted from the unitarized amplitudes. We compare these two approaches and provide predictions for different correlated pairs. Our results can be tested against current and future experimental data from the ALICE and STAR collaborations in both proton-proton and heavy-ion collisions.

    hep-phnucl-exnucl-thPRD(2026)·4 citations
14. 14*

    Monophotons from Scalar Portal Dark Matter at Neutrino Experiments

    Bhaskar Dutta🇺🇸 · Debopam Goswami🇺🇸 · Aparajitha Karthikeyan🇺🇸

    In this work, we investigate monophoton signatures arising from dark matter via a $2\to 3$ scattering process $\chi +N\to \chi +N+\gamma$ that is mediated by a virtual scalar and a Standard Model photon. Since the final-state photon carries a large fraction of the initial dark matter's energy, this process offers a compelling handle for probing scalar portal dark matter scenarios. Their distinctive energy, angular, and timing distributions allow for effective separation of signal from neutrino-induced backgrounds. We analyze several models featuring different couplings to the scalar mediator, with the scalar photon coupling serving as the common detection channel. To distinguish between the models, we further examined their distinct spatial distributions. We considered the flux of dark matter produced both at the target and absorber of neutrino facilities such as the BNB, NuMI, and LBNF, and investigated the sensitivities at the ongoing SBND, ICARUS-NuMI, and future DUNE ND detectors. We further investigated the differences in the DM fluxes arising from various production mechanisms, as well as the distinctions between the target and absorber contributions. Our results demonstrate that the sensitivities at the considered experiments, especially DUNE ND, can place significantly improved constraints on viable parameter space in various scenarios.

    hep-phJHEP(2026)·4 citations
15. 15*

    Non-holomorphic Contributions in GMSB with Adjoint Messengers

    Busra Nis🇹🇷 · Cem Salih Un🇹🇷

    We consider models of gauge mediated supersymmetry breaking, in which the breaking is transmitted to the visible sector by the messenger fields from the adjoint representation of MSSM's gauge group. We include the non-holomorphic terms induced by the supersymmetry breaking and involve them in the renormalization group evolution. The main impact from the non-holomorphic terms arises in the right-handed stau mass, which requires large hypercharge interactions with the messengers to accommodate non-tachyonic staus. With the non-holomorphic terms, the stau mass-square can remain positive in the renormalization group evolution, even if the hypercharge interactions are small. Although the radiative non-holomorphic contributions enhance the mass spectrum, their effects in the sparticle mixing rather reduce their overall contributions such that we realize about 25 GeV difference in the right-handed stau mass, while the difference is lowered by about 5 TeV in the lightest mass-eigenstate of staus. We realize 6-7 TeV difference in the sbottom mass, and about 15 TeV in the stop mass. These contributions in the sparticle masses also affect the SM-like Higgs boson mass, and we find that the SM-like Higgs boson can be enhanced as much as about 80 GeV. In a small region of the parameter space we also observe negative non-holomorphic contributions which do not exceed about 1 TeV for the sparticles, and 20 GeV for the SM-like Higgs boson. An interesting impact from the non-holomorphic terms happens in the muon g-2 results. We find that the non-holomorphic contributions can provide a significant decreasing in supersymmetric contributions to muon g-2. We realize that the muon g-2 results can be decreased as much as about -50 x 10^-10 by the non-holomorphic contributions, and consequently one can still accommodate light sleptons and gauginos in the spectrum.

    hep-phEPJC(2026)·3 citations
16. 16*

    Multiple Axions Save High-Scale Inflation

    Dan Kondo🇯🇵 · Hitoshi Murayama🇺🇸

    Many models of dark matter QCD axion requires inflation at a scale $H_{\text{inf}}\lesssim 10^6$~GeV and hence does not allow for a detectable tensor mode fluctuation. This is because the domain wall problem forces the Peccei--Quinn symmetry to be broken during the inflation and the axions to be produced by the misalignment mechanism. We point out that theories with multiple axions can evade this constraint and allow for a high-scale inflation with detectable tensor mode. It only requires a condition on the anomaly coefficients so that there is a unique minimum for the axion potential without a fine-tuning or small parameters.

    hep-phJCAP(2025)·5 citations
17. 17*

    Particles, Forces and the Early Universe

    Risto Raitio🇫🇮

    This article reveals the unexpected result that three a priori distinct ideas--global supersymmetry of preons, Hartle-Hawking cosmology, and Chern-Simons quantum gravity--share common concepts that offer paths beyond the Standard Model. Differences from the MSSM are discussed.

    hep-phgr-qcNPB(2025)·1 citation
18. 18*

    Dark, deep, deconfining: Phase transitions in neutron stars as powerful probes of hidden sectors

    Aryaman Bhutani🇮🇳 · Nirmal Raj🇮🇳 · Zenia Zuraiq🇮🇳

    The interiors of neutron stars enjoy ideal conditions for the conversion of hadrons to a strange quark phase, theorized to be the stablest form of matter. Though numerous astrophysical means to prompt such a deconfinement phase transition have been suggested, they may be pre-empted by a large energy barrier for nucleation of quark matter droplets. We will show that interactions of hidden sectors of particles with nucleons may surmount the barrier if it exceeds deca-GeV energies, and spark a phase transition. The neutron star would then, depending on the equation of state of QCD matter, convert to a black hole and/or set off a gamma-ray burst (GRB). Using the observed existence of ancient neutron stars and estimates of the GRB rate, we then set some of the strictest (albeit conditional) limits on dark matter scatters, annihilations, and decays that are tens of orders stronger than those from terrestrial searches. For smaller energy barriers, lower limits on nucleon decay lifetimes of the order of $10^{64}$~yr may be obtained.

    hep-phastro-ph.HEhep-exPRD(2026)·3 citations
19. 19*

    Quark flavors in hot and dense holographic QCD: setup and comparison to data

    Matti Jarvinen🇰🇷 · Toshali Mitra🇩🇪

    We establish a flavor dependent holographic framework for hot and dense QCD. To this end, we generalize a class of bottom-up holographic models for QCD in the Veneziano limit (V-QCD) by incorporating explicit flavor dependence. Specifically, we develop a $2+1$ flavor model characterized by two massless light quarks and a massive strange quark. Including the non-zero quark mass modifies the tachyon dependence of the model action, which yields a good agreement with the lattice data for thermodynamics in QCD in the low baryon number density and high temperature limit. We compare the model with various hadron resonance gas models at low temperature. We also compute the equation of state (EOS) at high density and low temperatures and found a smooth matching of this EOS with the nuclear matter EOS, suggesting significantly lower latent heat of the nuclear to quark matter transition than in earlier version of the V-QCD model. We observe that the smooth matching with the nuclear theory EOS is only applicable to a subset of potentials; furthermore, constraining the predictions of the model by limiting the potential parameters. We also identify the relevant fixed points of the model, particularly AdS${}_2$ and AdS${}_5$ fixed points.

    hep-phhep-thJHEP(2026)·4 citations
20. 20*

    Braneworld Dark Energy in light of DESI DR2

    Swagat S. Mishra🇬🇧 · William L. Matthewson🇰🇷 · Varun Sahni🇮🇳 · Arman Shafieloo🇰🇷 · Yuri Shtanov🇺🇦

    Recent observational results from the DESI collaboration reveal tensions with the standard $\Lambda$CDM model and favour a scenario in which dark energy (DE) decays over time. The DESI DR2 data also suggest that the DE equation of state (EoS) may have been phantom-like ($w<-1$) in the past, evolving to $w>-1$ at present, implying a recent crossing of the phantom divide at $w=-1$. Scalar field models of DE naturally emerge in ultraviolet-complete theories such as string theory, which is typically formulated in higher dimensions. In this work, we investigate a broad class of $thawingscalarfieldmodels$, including the simple quadratic, quartic, exponential, symmetry-breaking and axion potentials, propagating on a (4+1)-dimensional ghost-free phantom braneworld, and demonstrate that their effective EoS exhibits a phantom-divide crossing. Alongside the Hubble parameter and EoS of DE, we also analyse the evolution of the $Om$ diagnostic, and demonstrate that the time dependence of these quantities is in excellent agreement with the DESI DR2 observations. Furthermore, we perform a comprehensive parameter estimation using Markov Chain Monte Carlo sampling, and find that the ${\chi }^2$ values for all our models are remarkably close to that of the widely used CPL parametrisation, indicating that our models fit the data very well.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2025)·39 citations
21. 21*

    20 GeV halo-like excess of the Galactic diffuse emission and implications for dark matter annihilation

    Tomonori Totani🇯🇵

    Fifteen years of the Fermi Large Area Telescope (LAT) data in the halo region of the Milky Way (MW) are analyzed to search for gamma rays from dark matter annihilation. Gamma-ray maps within the region of interest ($|l|\le 60^{\circ }$, $10^{\circ }\le |b|\le 60^{\circ }$) are modeled using point sources, the GALPROP models of cosmic-ray interactions, isotropic background, and templates of Loop I and the Fermi bubbles, and then the presence of a halo-like component is further examined. A statistically significant halo-like excess is found with a spectral peak around 20 GeV, while its flux is consistent with zero below 2 GeV and above 200 GeV. Examination of the fit residual maps indicates that a spherically symmetric halo component fits the map data well. The radial profile agrees with annihilation by the smooth NFW density profile, and may be slightly shallower than this, especially in the central region. Various systematic uncertainties are investigated, but the 20 GeV peak remains significant. In particular, the halo excess with a similar spectrum is detected even relative to the LAT standard background model, which contains non-template patches adjusted to match the observed map. The halo excess spectrum can be fitted by annihilation with a particle mass $m_{\chi }\sim$ 0.5-0.8 TeV and cross section $⟨\sigma \upsilon ⟩\sim$ (5-8)$\times 10^{-25}\mathrm{c}{\mathrm{m}}^3{\mathrm{s}}^{-1}$ for the $b\bar{b}$ channel. This cross section is larger than the upper limits from dwarf galaxies and the canonical thermal relic value, but considering various uncertainties, especially the density profile of the MW halo, the dark matter interpretation of the 20 GeV ``Fermi halo'' remains feasible. The prospects for verification through future observations are briefly discussed.

    ↳ astro-ph.HEastro-ph.COhep-phJCAP(2025)·24 citations
22. 22*

    Lattice investigation of custodial two-Higgs-doublet model at weak quartic couplings

    Guilherme Catumba🇪🇸 · Atsuki Hiraguchi🇹🇼 · Wei-Shu Hou🇹🇼 · Karl Jansen🇩🇪 · Ying-Jer Kao🇹🇼 · C.-J. David Lin🇹🇼 · Alberto Ramos🇪🇸 · Mugdha Sarkar🇹🇼

    The $SU(2)-$gauged custodial two-Higgs-doublet model, which shares the same global-symmetry properties with the standard model, is studied non-perturbatively on the lattice. The additional Higgs doublet enlarges the scalar spectrum and opens the possibility for spontaneous breaking of the global symmetry. In this work we start by showing the occurrence of spontaneous breaking of the custodial symmetry in a region of the parameter space of the model. Following this, both the spectrum and the running of the gauge coupling are examined at weak quartic couplings in the presence of the custodial symmetry. The calculations are performed with energy cutoffs ranging from 300 to 600 GeV on a line of constant standard model physics, obtained by tuning bare couplings to fix the ratio between the masses of the Higgs and the $W$ bosons, as well as the value of the renormalized gauge coupling at the scale of the $W$ boson mass. The realizable masses for the additional scalar states are explored. For the choice of bare quartic couplings in this work, the estimated lower bound of these masses is found to be well below the $W$ boson mass, and independent of the cutoff. We also study the finite temperature electroweak transition along this line of constant standard model physics, revealing properties of a smooth crossover behavior.

    ↳ hep-lathep-phJHEP(2025)·2 citations
23. 23*

    Exploring non-cold dark matter in a scenario of dynamical dark energy with DESI DR2 data

    Tian-Nuo Li🇺🇸 · Peng-Ju Wu🇨🇳 · Guo-Hong Du🇺🇸 · Yan-Hong Yao🇨🇳 · Jing-Fei Zhang🇺🇸 · Xin Zhang🇺🇸

    Recent observations of DESI hint that dark matter (DM) may not be cold but have a non-zero equation of state (EoS) parameter, and that dark energy (DE) may not be a cosmological constant. In this work, we explore the possibility of a non-zero DM EoS parameter within the framework of dynamical DE. We perform analysis by using the latest baryon acoustic oscillation (BAO) data from DESI DR2, the cosmic microwave background (CMB) data from Planck, and the type Ia supernova (SN) data from DESY5 and PantheonPlus. When using the combination of CMB, BAO, and SN data, our results indicate a preference for a non-zero DM EoS parameter at the $2.8\sigma$ and $3.3\sigma$ level within the content of a constant DE EoS. In contrast, for a time-evolving DE EoS parameterized by $w_0$ and $w_a$, this preference decreases to $0.8\sigma$ and $1.1\sigma$. Furthermore, allowing a non-zero DM EoS yields best-fit values of $w_0$ and $w_a$ that exhibit smaller deviations from the $\Lambda$CDM expectations, and Bayesian evidence analysis shows a comparable preference for this model relative to $\Lambda$CDM. The overall results of this work indicate that a non-zero DM EoS parameter warrants further exploration and investigation.

    ↳ astro-ph.COgr-qchep-phPhys.Dark Univ.(2025)·59 citations
24. 24*

    Modeling Uncertainties on the Z Boson Background in the Context of High Precision W Boson Mass Measurements

    Maarten Boonekamp🇫🇷 · Matthias Schott🇩🇪 · Chen Wang🇩🇪

    The precise determination of the $W$ boson mass, $m_W$, is a cornerstone of electroweak precision tests and a critical input to global fits of the Standard Model (SM). While most existing measurements of $m_W$ are in agreement with SM predictions, the recent result from the CDF collaboration exhibits a significant deviation from the SM prediction but also exceeding $4\sigma$ from the global average of all other high precision measurements. This prompts renewed scrutiny of potential sources of systematic bias. In this study, we investigate the modeling of the $Z$ boson background, which is particularly relevant in the muon decay channel of the $W$ boson, where undetected muons can mimic missing transverse momentum. Using updated theoretical predictions and high-precision simulations, we construct reweighted templates to evaluate the impact of possible mismodeling in the $Z$ background. Our analysis suggests that such effects can induce a shift in the extracted $m_W$ value of up to 8~MeV in the muon decay channel. While this shift is non-negligible and exceeds the originally quoted uncertainty from this source, it remains insufficient to explain the full discrepancy observed in the CDF measurement.

    ↳ hep-exhep-phEPJC(2026)·0 citations
25. 25*

    Probing small-scale primordial power spectra with induced gravitational waves

    Di Wu🇨🇳 · Zhi-Chao Li🇨🇳 · Peng-Yu Wu🇨🇳 · Fei-Yu Chen🇨🇳 · Jing-Zhi Zhou🇨🇳

    Large-scale primordial perturbations have been well constrained by current cosmological observations, but the properties of small-scale perturbations remain elusive. This study focuses on second-order induced gravitational waves generated by large-amplitude primordial scalar and tensor perturbations on small scales. In this case, the induced gravitational waves include contributions from three types of source terms: scalar-scalar, tensor-scalar, and tensor-tensor. To distinguish them from second-order scalar induced gravitational waves (SIGWs), we refer to those generated by these three source terms as tensor-scalar induced gravitational waves (TSIGWs). We provide the analytical expressions for the kernel functions and the corresponding energy density spectra of second-order TSIGWs. By combining observations of stochastic gravitational wave background (SGWB) across different scales, TSIGWs can be used to constrain small-scale primordial curvature perturbations and primordial gravitational waves. Furthermore, we discuss the feasibility of TSIGWs dominating the current pulsar timing array (PTA) observations under various primordial power spectra scenarios. Our results indicate that TSIGWs generated by monochromatic primordial power spectra might be more likely to dominate the current PTA observations.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2026)·4 citations
26. 26*

    A case study of GW190425 for classifying binary neutron star versus binary black hole mergers and constraining asymmetric dark matter with gravitational wave detectors

    Sanika Khadkikar🇺🇸 · Divya Singh🇺🇸

    The LIGO Scientific, Virgo, and KAGRA collaboration has identified two binary neutron star merger candidates, GW170817 and GW190425, along with several binary black hole candidates. While GW170817 was confirmed as a BNS merger through its electromagnetic counterparts, GW190425 lacked such observations, leaving its classification uncertain. We examine the possibility that GW190425 originated from black holes that merged after dark matter accretion caused their progenitor neutron stars to implode. Using this event, we place constraints on dark matter parameters, such as its mass and interaction cross section. We simulate GW190425-like events and analyze them using future gravitational wave detector networks, including upcoming upgrades to current detector networks and next-generation observatories. We show that a network with A+ sensitivity can not classify a GW190425-like event with sufficient confidence. Detector networks with A# sensitivity can classify such events only if the neutron stars follow a relatively stiff equation of state, whose stronger tidal imprint differs measurably from a binary black hole waveform. Next-generation observatories like the Einstein Telescope and Cosmic Explorer recover the tidal signature even for soft, compact stars, enabling confident classification. Finally, we forecast the dark matter constraints that future gravitational wave networks could achieve for similar events.

    ↳ astro-ph.HEgr-qchep-phPRD(2026)·6 citations
27. 27*

    A Semi-Analytic model for Effects of Fuzzy Dark Matter Granule Perturbations on Orbital Motion

    Yu Zhao🇺🇸 · Andrew Benson🇺🇸 · Xiaolong Du🇺🇸

    In fuzzy dark matter scenarios, the quantum wave nature of ultralight axion-like particles generates stochastic density fluctuations inside dark matter halos. These fluctuations, known as granules, perturb the orbits of subhalos and other orbiting bodies. While previous studies have simulated these effects using N-body techniques or modeled them statistically using diffusion approximations, we propose an alternative framework based on representing the perturbations as a Fourier series with random coefficients, which can be applied to individual orbits, not just populations. We extend the model to finite-size subhalos, identifying a critical length scale below which subhalos behave as point-mass particles. In contrast, larger subhalos exhibit suppressed perturbations from granules due to their extended mass profiles. Using FDM-Simulator, we validate our finite-size model by isolating granule accelerations and confirming their statistical effects on subhalo dynamics.

    ↳ astro-ph.COhep-phMNRAS(2025)·3 citations
28. 28*

    TAMBO: A Deep-Valley Neutrino Observatory

    TAMBO Collaboration: Carlos A. Argüelles🇺🇸 · José Bazo🇵🇪 · Christopher Briceño🇵🇪 · Mauricio Bustamante🇩🇰 · Saneli Carbajal🇵🇪 · Víctor Centa🇵🇪 · Jaco de Swart🇺🇸 · Diyaselis Delgado🇺🇸 · Tommaso Dorigo🇸🇪 · Anatoli Fedynitch🇹🇼 · Pablo Fernández🇪🇸 · Alberto M. Gago🇵🇪 and 17 other authors

    Although the field of neutrino astronomy has blossomed in the last decade, physicists have struggled to fully map the high-energy neutrino sky. TAMBO, a mountain-based neutrino observatory, aims to solve that issue -- and find clues of new physics along the way.

    ↳ astro-ph.HEhep-exhep-ph20 citations
29. 29*

    Fluctuations in Hill's equation parameters and application to cosmic reheating

    Leia Barrowes🇺🇸 · Fred C. Adams🇺🇸 · Anthony M. Bloch🇺🇸 · Scott Watson🇺🇸

    Cosmic inflation provides a compelling framework for explaining several observed features of our Universe, but its viability depends on an efficient reheating phase that converts the inflaton's energy into Standard Model particles. This conversion often proceeds through non-perturbative mechanisms such as parametric resonance, which is described by Hill's equation. In this work, we investigate how stochastic fluctuations in the parameters of Hill's equation can influence particle production during reheating. We show that such fluctuations can arise from couplings to light scalar fields, and can significantly alter the stability bands in the resonance structure, thereby enhancing the growth of fluctuations and broadening the region of efficient energy transfer. Using random matrix theory and stochastic differential equations, we decompose the particle growth rate into deterministic and noise-induced components and demonstrate analytically and numerically that even modest noise leads to substantial particle production in otherwise stable regimes. These results suggest that stochastic effects can robustly enhance the efficacy of reheating across a wide swath of parameter space, with implications for early Universe cosmology, UV completions involving multiple scalar fields, and the resolution of the cosmological moduli problem.

    ↳ astro-ph.COhep-phmath-phmath.MPPRD(2025)·2 citations
30. 30*

    Relativistic quantum mechanics and quantum field theory

    Urjit A. Yajnik🇮🇳

    Relativistic quantum mechanics can be considered to have begun with a search for wave equations corresponding to each intrinsic spin. However, relativistic quantum physics differs fundamentally from the non-relativistic wave mechanics. It requires a formalism allowing \ creation and destruction of particles. This gets proper treatment only in a framework called quantum field theory. This article is a semi-historic account of the intriguing new features which emerge as a part of quantum field theory. Such a discussion is impossible without a basic presentation of the formalism itself. Hence some mathematics is included in finer print. The article is directed mostly to those familiar with essential classical mechanics and basic quantum mechanics, though I strive to provide a flavour of the subject to the keenly interested non-physics reader.

    ↳ physics.hist-phhep-phhep-thquant-phJournal of the Indian Institute of Scienc…·0 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.