Mon·Apr 27, 2026Monday·April 27, 2026

1. 01*

   Solar Reflection of Inelastic Dark Matter

   Haipeng An🇨🇳 · Haoming Nie🇨🇳

   Solar-reflected dark matter (SRDM) consists of dark-matter particles up-scattered and accelerated by energetic electrons in the solar interior, producing a high-velocity tail that can enhance signals in direct-detection experiments, especially for MeV-scale masses. We consider an inelastic dark matter (iDM) model, in which solar scattering populates the excited state; subsequent de-excitation in terrestrial detectors releases the mass-splitting energy, substantially helping the energy release of the collision to be larger than the detector threshold. Using detailed Monte Carlo simulations, we generate the velocity and energy distributions of solar-reflected iDM over a range of dark-matter masses $m_{\chi }$ and mass splittings $\Delta$. We then compute event rates and energy depositions for current xenon and semiconductor experiments. Our results show that these experiments can place new constraints on the parameter space of MeV-scale iDM.

   hep-phastro-ph.SRhep-exPRD(2026)·0 citations
2. 02*

   Loop-Induced Higgs Boson Decays into Gauge Bosons in Radiative Natural Supersymmetry

   Edilson A. Reyes R🇧🇷

   In this article, we study loop-induced Higgs decays into gauge bosons within the framework of Radiative Natural Supersymmetry. We reproduce the one-loop MSSM calculations for the Higgs partial decay widths into a Z boson-photon pair, two photons, and two gluons, providing the corresponding analytical expressions for the scattering amplitudes. We focus on the region of parameter space that maximizes the rare decay width of the process $h\to Z\gamma$, and analyze the correlated predictions for the remaining Higgs decay channels. In the selected region of parameter space, the $h\to Z\gamma$ decay width is enhanced, reaching a maximum value of $\simeq 7.5\mathrm{keV}$, while remaining compatible with the current ATLAS measurement. At the same time, this region satisfies current Higgs constraints from the $h\to \gamma \gamma$ and $h\to gg$ channels. The diphoton mode remains close to the Standard Model expectation, with deviations at the level of $\lesssim 5\%$. The gluon channel exhibits a stronger sensitivity to the considered region of parameter space, leading to a moderate suppression of about $10\%$ in the corresponding partial width.

   hep-phPRD(2026)·0 citations
3. 03*

   Compositeness of near-threshold states in charged hadronic systems

   Tomon Kinugawa🇯🇵 · Tetsuo Hyodo🇯🇵

   We quantify the internal structure of near-threshold bound, virtual, and resonance states in systems where Coulomb and short-range interactions coexist by evaluating the compositeness. Using the Coulomb-modified effective range expansion, we derive an expression for the compositeness in terms of the eigenenergy and Coulomb effective range in the weak-binding limit. We then apply the formulation to several near-threshold states in hadronic and nuclear systems, including $pp$, $\alpha \alpha$, ${\Omega }^{-}{\Omega }^{-}$, ${\Omega }_{ccc}^{++}{\Omega }_{ccc}^{++}$, ${\Xi }^{-}\alpha$, and ${\Omega }^{-}p$.

   hep-phnucl-thJ.Subatomic Part.Cosmol.(2026)·0 citations
4. 04*

   Flavor specific chiral $U(1{)}_X$ framework for explaining the ATOMKI anomaly

   Aditya Batra🇵🇹 · F. R. Joaquim🇵🇹 · Hemant Prajapati🇮🇳 · Rahul Srivastava🇮🇳

   Recent anomalies in nuclear transitions observed by the ATOMKI Collaboration suggest the existence of a new boson with a mass of $\sim 17$ MeV. A theoretically consistent interpretation requires a framework that not only matches the kinematics but also reproduces the observed decay rates while satisfying stringent experimental constraints. Among various possibilities, an axial-vector or mixed vector--axial-vector mediator $Z^{\prime }$ emerges as the most viable candidate. However, getting such couplings for a light $Z^{\prime }$ gauge boson is a highly nontrivial task. In this work, we construct a gauged chiral, flavor specific $U(1{)}_X$ extensions of the Standard Model where the associated $Z^{\prime }$ boson acts as the $17$ MeV particle. By employing a two Higgs doublet framework, we generate the necessary nonvanishing axial-vector couplings while ensuring gauge anomaly cancellation and consistent fermion mass generation. Focusing on the ${}^8\mathrm{Be}$ and ${}^4\mathrm{He}$ signals, we show that in this model the viable parameter space to resolve the ATOMKI anomalies is also consistent with a diverse set of experimental constraints, including atomic parity violation, beam dump experiments, meson decays, and neutrino nucleus and neutrino electron scatterings. Our results demonstrate that this framework offers a theoretically sound and phenomenologically robust solution to the ATOMKI anomaly.

   hep-phPRD(2026)·4 citations
5. 05*

   Confronting Color Glass Condensate at next-to-leading order with HERA data

   Carlisle Casuga🇫🇮 · Heikki Mäntysaari🇫🇮

   We perform a global analysis of HERA total inclusive cross section and charm quark production data to extract the non-perturbative initial condition for the next-to-leading order Balitsky-Kovchegov (BK) equation. We extend our previous analyses to full next-to-leading order + next-to-leading logarithm (NLO+NLL) accuracy by combining the NLO DIS impact factors with the NLO BK equation that includes the resummation of large double and single logarithms. The developed Bayesian setup extracts the posterior that describes the distribution of the parameters that best fit the data. The posterior distribution allows for estimates of the theoretical uncertainty of the dipole amplitude and, hence, offers a streamlined method for propagating uncertainties in the BK initial condition in NLO CGC calculations.

   hep-phnucl-th3 citations
6. 06*

   Super-Heisenberg protocol for dark matter and high-frequency gravitational wave search

   Wakutaka Nakano🇯🇵 · Ryoto Takai🇯🇵

   We propose a quantum-enhanced sensing scheme for the detection of wave-like dark matter and high-frequency gravitational waves using two-dimensional ion crystals in a Penning trap. The protocol employs spin-motion squeezed states to improve the signal-to-noise ratio and enable a super-Heisenberg scaling with respect to the number of ions over a broad parameter range. We analyze the sensitivity of the protocol to representative wave-like dark matter candidates, including the axion-like particle and the dark photon, as well as to high-frequency gravitational waves, taking into account the decoherence and dephasing of the ion spins. Our results indicate that two-dimensional ion crystals and this new protocol provide a promising platform for probing previously unexplored parameter space in searches for light dark matter and high-frequency gravitational waves.

   hep-phgr-qcphysics.atom-phquant-phPRD(2026)·1 citation
7. 07*

   The possible $K^{\ast }{\Sigma }^{\ast }$ molecular state

   Yin Huang🇨🇳 · Dan Jiang🇨🇳 · Feng Zhang🇨🇳 · Bo Nan Zhang🇨🇳

   Within the framework of the one-boson-exchange model, we systematically investigate the interaction between the vector meson $K^{\ast }$ and the baryon ${\Sigma }^{\ast }$ with the aim of exploring the possibility of forming hadronic molecular states. The $K^{\ast }{\Sigma }^{\ast }$ interaction potential is constructed from $\rho$, $\omega$, and $\pi$ meson exchanges, and the nonrelativistic Schrödinger equation is solved using the Gaussian expansion method. The binding energies are calculated for different total angular momenta $J^P$ and isospin channels $I=1/2$ and $I=3/2$. Our results show that $S$--$D$ wave mixed $K^{\ast }{\Sigma }^{\ast }$ molecular states with $J^P=1/2^{-}$ can be formed only in the $I=3/2$ channel, while no bound state appears in the $I=1/2$ channel. In addition, the $S$--$D$ wave mixed states with $J^P=3/2^{-}$ and $J^P=5/2^{-}$ are also found to support bound-state solutions. For higher partial-wave states in our study, the binding mechanism mainly arises from the interplay between partial-wave mixing and non-central interactions. In particular, the $J^P=1/2^{+}$ channel does not support a bound state, as the meson-exchange interaction is predominantly repulsive. Our analysis further supports the interpretation of the experimentally observed $N(2250)$ and $\Delta (2200)$ states as $K^{\ast }{\Sigma }^{\ast }$ molecular candidates, corresponding to $I=1/2,J^P=9/2^{-}$ and $I=3/2,J^P=7/2^{-}$, respectively.

   hep-phhep-th0 citations
8. 08*

   QCD vacuum pressure and its influence on the equation of state of non-strange quark stars

   Cheng-Ming Li🇨🇳 · Guang-Hao Yu🇨🇳 · Ya-Peng Zhao🇨🇳 · Zhibin Li🇨🇳 · Jin-Li Zhang🇨🇳 · Yong-Liang Ma🇨🇳 · Yong-Feng Huang🇨🇳

   Solutions of the quark gap equation and the corresponding vacuum pressure are investigated within a modified Nambu-Jona-Lasinio model, which is a basic issue for studying the QCD equation of state (EOS) and the properties of hypothetical non-strange quark stars. In this study, the coupling strength $G$ is modified as $G=G_1+G_2⟨\bar{\psi }\psi ⟩$ to highlight the feedback effect of the quark condensate on the gluon propagator. Our analysis reveals that the influence of the vacuum pressure on EOS stiffness critically depends on whether the chiral phase transition is a first-order transition or a smooth crossover. A small ratio $G_1/G$ $(0.74\sim 0.75)$ leads to a low vacuum pressure and a first-order chiral phase transition, a scenario favored by the existence of massive pulsars. Conversely, a large $G_1/G$ $(>0.96)$ leads to a high vacuum pressure and a crossover, but the corresponding EOS is ruled out by recent pulsar mass-radius observations. The model parameter space, restricted by four constraints, indicates the current quark mass is in the range $4.08\le m\le 4.13$ MeV, with the quark condensate feedback contribution accounting for approximately 25\%. Furthermore, it is argued that the merging compact binary in GW170817 could be non-strange quark stars, and the tidal deformability is constrained to $\Lambda (1.4)\le 646$.

   hep-ph2 citations
9. 09*

   The exact column texture: tree-level Yukawa universality in heterotic $Z_3\times Z_3$ orbifolds

   Navid Ardakanian

   On $T^6/(Z_3\times Z_3)$ heterotic orbifolds where three quark generations arise from $Z_3$ fixed-point triplication, we prove that the leading-order tree-level Yukawa amplitude -- the three-point coupling among massless string states -- has an exact column texture: $Y_{\mathrm{lead}}(i,j)=c{\epsilon }^{q_R[j]}$, with the $O(1)$ coefficient $c$ universal across all left-handed generations $i$. Five independent lines of evidence are given: (1) the worldsheet instanton geometry on the $SU(3)$ root lattice gives identical areas for all non-degenerate triangles, making the geometric $O(1)$ coefficient exactly $1$; (2) the generation direction necessarily has trivial Wilson line, rendering all three generations gauge-identical, as verified across all 77 MSSM-like models in the Mini-Landscape classification; (3) an extension to two-Wilson-line models, verified on the complete Parr-Vaudrevange-Wimmer classification of 3,337 $Z_3\times Z_3$ MSSM models, confirms that no Wilson line configuration can break gauge blindness; (4) the Kähler metric is generation-universal by $\Delta (54)$ representation theory; (5) the full Froggatt-Nielsen chain computation with 534 trilinear superpotential couplings and vacuum-aligned singlet VEVs produces left-circulant Yukawa matrices whose eigenstructure is generation-universal. The Froggatt-Nielsen column texture is therefore not an approximation but an exact property of the leading-order string amplitude. Non-trivial $O(1)$ coefficients, which are required for CKM mixing angles beyond the Wolfenstein hierarchy, must originate from beyond-leading-order contributions: integrated-out heavy messenger propagators (tree-level in the low-energy effective theory), vacuum-alignment effects, multi-instanton corrections, or loop corrections.

   hep-phhep-th0 citations
10. 10*

    Machine Learning for Multi-messenger Probes of New Physics and Cosmology: A Review and Perspective

    Andrea Addazi🇨🇳 · Konstantin Belotsky🇷🇺 · Vitaly Beylin🇫🇷 · Timur Bikbaev🇷🇺 · Deen Chen🇨🇳 · Filippo Fabrocini🇨🇳 · Stefano Giagu🇮🇹 · Krid Jinklub🇨🇳 · Artem Kharakhashyan🇷🇺 · Maxim Khlopov🇫🇷 · Vladimir Korchagin🇷🇺 · Maxim Krasnov🇷🇺 and 9 other authors

    The multi-messenger exploration of dark matter and physics beyond the Standard Model has emerged as a central direction in modern astro-particle physics, particularly following the discovery of gravitational waves. In this work, we present a comprehensive review and forward-looking perspective on machine-learning-enhanced multi-messenger approaches, combining information from gravitational waves, cosmic rays, gamma rays, neutrinos, and collider experiments. We summarize the current state of the field, discuss recent methodological developments, and outline a coherent research program aimed at integrating heterogeneous datasets within a unified inference framework. Our collaboration proposes here a plan for forthcoming analyses aiming at extracting information on the properties and interactions of dark matter, and finally on its genesis, combining multi-messenger astronomy techniques and inputs from laboratory physics. The main objectives planned in this line of research comprise: i) the multi-messenger analysis of new physics in cosmology, including mainly, but not only, several different models of dark matter; ii) the phenomenology of new physics signatures in ground-based cosmic rays experiments, with cross-correlation to the corresponding physical, astrophysical and cosmological observations; iii) the development of machine learning methods for data analysis in ground-based cosmic rays experiments, in light of the new physics signatures. We note that several groups have explored the use of multi-messenger observations, including gravitational waves, to probe alternative dark matter candidates. The present work builds on these developments by focusing on the role of machine learning in integrating heterogeneous datasets. We foresee that such a cross-fertilizing approach will represent the right path to extract information about the main questions left in fundamental physics.

    hep-phastro-ph.COgr-qcSymmetry(2026)·0 citations
11. 11*

    Recent Developments in SMEFT: Theory, Tools, and Phenomenology

    Michał Ryczkowski🇮🇹

    Despite the remarkable success of the Standard Model in describing fundamental interactions, unresolved phenomena such as dark matter, dark energy, and matter-antimatter asymmetry strongly suggest the existence of physics beyond the Standard Model. The absence of new particle discoveries at the LHC indicates that such New Physics may be significantly heavier than the electroweak scale. In this context, Effective Field Theories offer a powerful framework for studying the indirect effects of heavy New Physics. This contribution reviews some of the recent advancements, computational tools, and phenomenology of Effective Field Theories, with a particular focus on the Standard Model Effective Field Theory.

    hep-phActa Phys.Polon.Supp.(2026)·0 citations
12. 12*

    The potential of directional neutrino detection to observe neutrino spin oscillations

    Konstantin A. Kouzakov🇷🇺 · Fedor M. Lazarev🇷🇺 · Alexander I. Studenikin🇷🇺

    A nonzero neutrino magnetic moment arises already in the minimally extended Standard Model with right-handed massive Dirac neutrinos. The well-known consequence of the neutrino magnetic moment is the phenomenon of neutrino spin oscillations in a magnetic field. It can manifest itself not only as a lack in the flux of active cosmic neutrinos arriving on Earth but also as characteristic features in low-energy neutrino elastic scattering processes. Following our approach developed earlier, in this work we study the influence of arbitrary spin-flavor state of incoming neutrino on low-energy neutrino scattering off different particles in a detector. We demonstrate that superposition of left- and right-handed helicity neutrino states gives rise to an azimuthal asymmetry in the angular distribution of the recoil momenta. We present numerical calculations for elastic neutrino scattering on electrons, protons and 40Ar and 132Xe nuclei, demonstrating the azimuthal-asymmetry effect. Our results indicate the unique potential of directional neutrino detection to observe the neutrino spin oscillations.

    hep-phhep-thPLB(2026)·0 citations
13. 13*

    Mechanisms of high energy polarized photoproduction of ${\pi }^{-}{\Delta }^{++}$

    Vanamali Shastry🇺🇸 · Łukasz Bibrzycki🇵🇱 · Vincent Mathieu🇪🇸 · Glòria Montaña🇪🇸 · Alessandro Pilloni🇮🇹 · César Fernández-Ramírez🇪🇸 · Robert J. Perry🇺🇸 · Arkaitz Rodas🇺🇸 · Adam P. Szczepaniak🇺🇸 · Daniel Winney🇲🇽

    We present an amplitude analysis of high-energy polarized photoproduction of ${\pi }^{-}{\Delta }^{++}$ within a Regge exchange framework. A Regge amplitude model incorporating $\pi$, $\rho$, $b_1$, and $a_2$ trajectory exchanges is fit simultaneously to spin density matrix elements measured by the GlueX experiment at photon energies of $E_{\gamma }=8.2$--$8.8$ GeV and differential cross section data from SLAC. By including SDME data, the fit constrains not only the magnitudes but also the relative phases of the helicity amplitudes. The results confirm the dominance of pion exchange at small momentum transfer, while natural parity exchanges become significant at larger $t$. We analytically continue the $s$-channel amplitude to the $t$-channel, taking care of the kinematical singularities, and isolate the dynamical residues at the meson poles. The extracted $\pi N\Delta$ coupling constant is found to be consistent with the value obtained from the decay width of the $\Delta (1232)$. For the $\rho N\Delta$, $b_{1}N\Delta$, and $a_{2}N\Delta$ vertices, first extractions of the relevant coupling constants are provided.

    hep-phnucl-th2 citations
14. 14*

    Dalitz Plot Kinematics for a Lorentz-Violating Three-Body Decay

    Joshua O'Connor

    We outline the analysis of three-particle interactions and decay processes for leading-order modifications in a Lorentz-violating quantum field theory.

    hep-phPRD(2025)·2 citations
15. 15*

    Inclusive semileptonic $D_s\to X_s\ell \bar{\nu }$ decays from lattice QCD: continuum and chiral extrapolation

    Ryan Kellermann🇯🇵 · Alessandro Barone🇩🇪 · Ahmed Elgaziari🇬🇧 · Shoji Hashimoto🇯🇵 · Zhi Hu🇯🇵 · Andreas Jüttner🇨🇭 · Takashi Kaneko🇯🇵

    We present results for the inclusive semileptonic $D_s\to X_s\ell \bar{\nu }$ decay rate from lattice QCD. Chiral and continuum extrapolations are performed using gauge ensembles generated with 2+1 flavours of Möbius domain-wall fermions. Systematic errors are fully addressed including those from the integral over all possible final states. Our results are in agreement with currently available experimental data, with an error at the few-percent level.

    ↳ hep-lathep-phPRD(2026)·4 citations
16. 16*

    Vacuum structure of a scalar field on a torus with uniform magnetic flux

    Mayumi Akamatsu🇯🇵 · Hiroki Imai🇯🇵 · Makoto Sakamoto🇯🇵 · Maki Takeuchi🇯🇵

    We investigate the vacuum expectation value of a complex scalar field on a two-dimensional torus with quantized magnetic flux $M$. A characteristic feature of this system is the emergence of a critical area: when the area of the torus exceeds this critical value, the vacuum expectation value becomes nonvanishing. Furthermore, any nonzero vacuum expectation value necessarily exhibits nontrivial dependence on the coordinates of the torus. Employing the lowest-mode approximation, we find a single vacuum configuration for $M=1$, whereas two and six degenerate vacuum configurations arise for $M=2$ and $M=3$, respectively. We then analyze the symmetry properties of these vacuum configurations and determine whether they preserve or spontaneously break the symmetry of the underlying system.

    ↳ hep-thhep-ph0 citations
17. 17*

    Five benefits of grand unified $SU(5)$ brane world scenario

    Masato Arai🇯🇵 · Filip Blaschke🇨🇿 · Minoru Eto🇯🇵 · Masaki Kawaguchi🇨🇳

    We construct an $SU(5)$ Grand Unified Theory on domain walls in the five-dimensional space-time. In this setup, we introduce an adjoint scalar field and a singlet that together form a set of five domain-wall solutions, realizing a dynamical brane-world. The same scalar fields also localize chiral fermion zero modes around the walls via the Jackiw-Rebbi mechanism, break $SU(5)$ down to the Standard Model gauge group via geometric Higgs mechanism and simultaneously trap gauge fields through a field-dependent gauge kinetic term. Furthermore, they enable localization of the Higgs field, providing a novel solution to the doublet-triplet splitting problem. As a result, all essential ingredients of the model are realized by a single adjoint scalar field and a singlet, making the construction very economical. We propose two realizations of the Higgs sector, derive the four-dimensional effective theory, and demonstrate that the Standard Model Yukawa couplings at the weak scale can be reproduced from the five-dimensional Yukawa couplings by the renormalization group analysis with a suitable choice of parameters.

    ↳ hep-thhep-phPRD(2026)·0 citations
18. 18*

    Four-dimensional QCD equation of state from a quasi-parton model with physics-informed neural networks

    Fu-Peng Li🇨🇳 · Long-Gang Pang🇨🇳 · Guang-You Qin🇨🇳

    The equation of state (EoS) of strongly interacting matter at finite temperature and chemical potentials (baryon, charge, and strangeness) is a crucial input for hydrodynamic simulations of relativistic heavy-ion collisions. We construct a four-dimensional EoS using a deep-learning-assisted quasi-particle model (DLQPM) within a physics-informed neural network (PINN) framework, in which the masses of light quarks, strange quarks, and gluons are parameterized as functions of temperature and chemical potentials ($T,{\mu }_B,{\mu }_Q,{\mu }_S$). The model is constrained by lattice QCD data at vanishing chemical potentials and provides a thermodynamically consistent extrapolation to finite ${\mu }_{B,Q,S}$. The DLQPM accurately reproduces the lattice-calculated cumulants ${\chi }_{i,j,k}^{B,Q,S}$ at ${\mu }_{B,Q,S}=0$, and its predicted EoS at various chemical potentials agrees well with results from the generalized $T^{\prime }$-expansion method in lattice QCD. Furthermore, the calculated baryon-strangeness correlation $C_{BS}$ is consistent, within uncertainties, with preliminary STAR data. This work offers a reliable EoS for exploring the QCD phase structure in the beam energy scan region.

    ↳ nucl-thhep-ph1 citation
19. 19*

    Two flavor neutrino oscillations in presence of non-Hermitian dynamics

    Kritika Rushiya🇮🇳 · Gaurav Hajong🇮🇳 · Bhabani Prasad Mandal🇮🇳 · Poonam Mehta🇮🇳

    We develop a consistent mathematical framework for studying two flavor neutrino oscillations in presence of non-Hermitian dynamics. We consider two approaches : (a) bi-orthonormal inner product defined by a positive-definite metric operator $\mathcal{G}$ and (b) the density matrix prescription by Brody and Graefe [Phys. Rev. Lett. 109, 230405 (2012)]. For the $\mathcal{P}\mathcal{T}$-symmetric case, we show that the $\mathcal{G}$ metric approach does not work well (probabilities are not conserved) both in $\mathcal{P}\mathcal{T}$-unbroken as well as $\mathcal{P}\mathcal{T}$-broken regime. Hence, we adopt the density matrix prescription by Brody and Graefe which is a positive semi-definite map. In the density matrix prescription, we note that probability in the steady state limit is not necessarily $1/2$ thereby indicating non-Markovian behavior.

    ↳ quant-phhep-phhep-th0 citations
20. 20*

    Quark Number Susceptibilities and Conserved Charge Fluctuations in $(2+1)$-flavor QCD with Möbius domain-wall fermions (MDWF)

    Jishnu Goswami🇩🇪 · Yasumichi Aoki🇯🇵 · Hidenori Fukaya🇯🇵 · Shoji Hashimoto🇯🇵 · Issaku Kanamori🇯🇵 · Takashi Kaneko🇯🇵 · Yoshifumi Nakamura🇯🇵 · David Ward🇯🇵 · Yu Zhang (JLQCD Collaboration)🇩🇪

    We calculate second- and selected fourth-order conserved-charge fluctuations in $(2+1)$-flavor QCD using Möbius domain-wall fermions (MDWF) along a line of constant physics. Gauge ensembles were generated for two light-to-strange quark-mass ratios, $m_l/m_s=1/10$ and $1/27.4$, corresponding to heavier-than-physical and physical pion masses, respectively. For $m_l/m_s=1/10$, calculations were carried out on lattices with temporal extents $N_{\tau }=12$ and $16$, enabling an assessment of lattice-spacing effects at heavier pion mass. For $m_l/m_s=1/27.4$, calculations were performed at $N_{\tau }=12$, allowing us to study the light-quark-mass dependence down to the physical point. Below the pseudocritical temperature, second-order electric-charge, strangeness, and off-diagonal conserved-charge fluctuations are consistent with QMHRG2020 hadron resonance gas calculations. Across the crossover region, these observables rise rapidly and tend toward their Stefan--Boltzmann limits. Selected fourth-order cumulants were also computed at the physical pion mass. Although these observables are statistically more demanding, several channels with controlled uncertainties permit a first comparison with hadron resonance gas calculations.

    ↳ hep-lathep-ph4 citations
21. 21*

    The Effect of Mass Loss and Convective Overshooting on the Pre-Collapse Structure, Composition, and Neutrino Emission of Red Supergiants

    McKenzie A. Myers · Claire B. Campbell · Kelly M. Patton · Segen BenZvi🇺🇸 · Marta Colomer Molla🇧🇪 · Alec Habig🇺🇸 · James P. Kneller🇺🇸 · Dan Milisavljevic · Jeffrey Tseng

    Prior to core collapse, the neutrino emission from red supergiants (RSGs) is so large that a nearby ($\lesssim 1$kpc) RSG will become visible in current and near-future neutrino detectors. The rate of emission and the spectra of the pre-supernova (pre-SN) neutrinos from RSGs are sensitive to the temperature, density, and detailed isotopic composition of the core. During the last year of the star's life, these properties change considerably. Several factors of stellar evolution modeling - such as the treatment of mass loss and convective overshooting - alter the thermal conditions and composition of the RSG core as it approaches collapse. In this paper we present the first study of how varying the treatment of mass loss and convective overshooting together affects the pre-collapse core properties and neutrino emission of RSGs. We use the stellar evolution instrument MESA and construct a grid of 32 models with zero-age main sequence masses of $\{12,15,18,20\}$ $M_{\odot }$, use the so-called 'Dutch' mass-loss scheme with wind efficiencies of $\{0.2,0.4,0.8,1.0\}$, and consider two convective overshooting schemes. Our models use a large 206-isotope nuclear network in order to accurately compute the structure and composition of the star. We find that, in the last few days of the star's life, the general trend of the conditions and composition in the core of the star is one of contraction, heating, and deleptonization, but that during this phase, this general trend will be interrupted by the initiation of core silicon burning and shell burning episodes that cause the core to expand and undergo convective mixing with material of a higher proton fraction that temporarily reverses the deleptonization. The pre-SN neutrino emission reflects these changes with a gradual shift to higher energies and larger flux that becomes dominated by beta processes a few hours prior to the collapse.

    ↳ astro-ph.SRastro-ph.HEhep-phnucl-th2 citations
22. 22*

    Dense Matter and Compact Stars in Strong Magnetic Fields

    Monika Sinha🇮🇳 · Vivek Baruah Thapa🇮🇳

    Compact stars serve as natural systems where matter exists at densities far beyond those achievable in laboratory experiments. Among them, magnetars are expected to possess interior magnetic fields that may reach values of the order of $10^{17}-10^{18}$ G. These extreme conditions are expected to alter the microscopic and macroscopic properties of dense matter. In this review, we examine how strong magnetic fields affect fermionic matter through mechanisms such as Landau quantization and anomalous magnetic moment interactions. We further discuss the behaviour of magnetized hadronic matter within relativistic mean-field approaches and consider the possible emergence of additional degrees of freedom, including hyperons, $\Delta$ resonances, meson condensates and quark matter. The consequences of these effects for neutron-star structure and observational constraints are also briefly outlined.

    ↳ astro-ph.HEhep-phnucl-thUniverse(2026)·4 citations
23. 23*

    Gauge-independent approach to inflation in quadratic gravity

    Adrian Palomares🇨🇳 · Ying-li Zhang🇨🇳 · Jinsu Kim🇨🇳

    We investigate the scalar sector of linear cosmological perturbations in quadratic gravity. Working in the Einstein frame, we derive the equations of motion in a gauge-independent manner and express them in terms of three sets of gauge-invariant variables. This approach allows us to distinguish genuine physical effects from gauge artefacts, which is particularly relevant for assessing the stability of perturbations in this theory. In the superhorizon limit, we obtain the leading-order behaviour of the relevant gauge-invariant variables and analyse the perturbations in commonly used gauges. We find that the Newtonian gauge exhibits an apparent instability, characterised by the exponential growth of the metric perturbations. However, this growth is non-generic and gauge-dependent; in the other gauges analysed in this work, the perturbations remain well behaved within the perturbative regime. Our analysis also demonstrates how the evolution behaviour of a gauge-invariant variable changes under the frame transformation and clarifies the relation between results obtained in the Jordan and Einstein frames.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2026)·0 citations
24. 24*

    Precision Analysis for ${\mathbf{H}}_0$ Using Upcoming Multi-band Gravitational Wave Observations

    Setabuddin🇮🇳 · Md Riajul Haque🇮🇳 · Ratna Koley🇮🇳 · Supratik Pal🇮🇳

    We investigate how multi-band gravitational wave (GW) observations can constrain the uncertainties in the Hubble parameter ($H_0$) using primordial black holes (PBHs) as possible sources. Our framework combines scalar-induced and merger-induced GWs from PBHs, and forecasts on a combination of two future detectors Square Kilometre Array (SKA) and the Einstein Telescope (ET), enabling a multi-band analysis. We perform a statistical forecast of the PBH parameters, $M_{\mathrm{PBH}}$ and $f_{\mathrm{PBH}}$, using signal-to-noise ratio (SNR) estimates and Fisher matrix analysis. Imposing $\mathrm{SNR}\ge 1$, we identify the accessible PBH parameter space and propagate these uncertainties to estimate the corresponding uncertainties in $H_0$. For $\delta {\theta }_i/{\theta }_i\le 0.1$, with ${\theta }_i\equiv M_{\mathrm{PBH}}(f_{\mathrm{PBH}})$, we find $\delta H_0\lesssim 2\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$ in a conservative approach, improving to $\delta H_0\lesssim \mathcal{O}(0.1)\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$ for $\delta {\theta }_i/{\theta }_i\le 0.01$ for an optimistic approach of precision measurement. The results are further found to be largely insensitive to the fiducial choice of the $H_0$, with only moderate dependence on the PBH collapse efficiency. These findings demonstrate that multi-band GW observations provide an independent and complementary approach to constraining the uncertainties in $H_0$, with the potential to provide a novel, cosmic distance ladder-independent measure of the Hubble parameter.

    ↳ astro-ph.COgr-qchep-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.