Thu·Nov 20, 2025Thursday·November 20, 2025

1. 01*

   Probing Axion via Mössbauer Spectroscopy

   Shengyi Liu🇨🇳 · Kun-Feng Lyu🇺🇸 · Jie Meng🇨🇳 · Jing Shu🇨🇳 · Yakun Wang🇨🇳 · Yue Zhao🇨🇳

   We propose using the ultra-narrow 88 keV Mössbauer transition in ${}^{109}$Ag to search for QCD axion dark matter. The sub-eV axion field oscillates coherently, inducing a time-varying effective ${\bar{\theta }}_{\mathrm{QCD}}$ angle. This, in turn, modulates the nuclear binding energy. From existing linewidth measurements, we derive constraints on the $f_a^{-1}$-$m_a$ plane that already surpass other laboratory bounds. We further detail an experimental setup to directly probe this time-dependent signature via precision Mössbauer spectroscopy in the gravitational potential. This Letter demonstrates that this approach can significantly extend search capability and probe a vast, unexplored region of axion parameter space. Particularly, this setup can probe axion masses beyond the reach of existing experiments, such as atomic-clock measurements, offering a powerful new way for exploring higher-mass axion dark matter. The sensitivity has the potential to be further improved with advancing experimental capabilities.

   hep-phnucl-ex1 citation
2. 02*

   511 keV Gamma Ray Echo from Particle Decays in Supernovae

   Garv Chauhan🇺🇸 · Cecilia Lunardini🇺🇸

   The formation of a hot and dense core in a core-collapse supernova (SN) can produce massive Beyond Standard Model (BSM) particles. These particles can decay in the stellar envelope, generating positrons either directly or through secondary processes involving neutrinos or photons. We show for the first time that such positrons regardless of their production channel, can thermalize and annihilate at rest with ambient electrons in the outer SN envelope, producing a characteristic echo of 511 keV gamma rays. For axion-like particles (ALPs), we derive bounds on the ALP-photon coupling ($G_{a\gamma }$) using Pioneer Venus Orbiter observations of SN 1987A. We also evaluate the sensitivity of upcoming MeV gap gamma-ray telescopes in the 511 keV range, such as COSI and AMEGO, for future Galactic SNe, which can improve existing constraints or enable ALP discovery. The echo signal is a generic prediction for any particle species that efficiently produces positrons near the stellar surface.

   hep-phastro-ph.HE3 citations
3. 03*

   Improved cosmological constraints on axion-lepton interactions

   Marcin Badziak🇵🇱 · Adam Gomułka🇵🇱 · Maxim Laletin🇵🇱 · Krzysztof Szafrański🇵🇱

   We present updated cosmological constraints on axion-lepton interactions based on state-of-the-art computations of the thermal axion abundance. By combining Planck Cosmic Microwave Background (CMB) data with baryon acoustic oscillation (BAO) measurements from DESI DR2, we derive improved limits on both lepton-flavor-conserving (LFC) and lepton-flavor-violating (LFV) axion couplings. Incorporating finite axion mass effects substantially strengthens the bounds for axion masses above 0.1 eV compared to those inferred from the $\Delta N_{\mathrm{eff}}$ constraint alone. The bounds on the LFC axion-tau coupling and LFV axion couplings to tau and muon or electron are improved by several orders of magnitude and the lower bound on the axion decay constant may exceed $10^6$ and $10^8$ GeV, respectively, for axion masses above 1 eV. Our cosmological constraints on LFC axion couplings to muons and taus and LFV axion couplings to tau and muon or electron are stronger than all other constraints for masses above 0.3 eV. In particular, they are stronger than recent collider constraints from Belle-II on $\tau \to la$ decays, where $l=e$ or $\mu$. The collider constraints on $\mu \to ea$ decays are weaker than the cosmological constraints for axion masses above 100 eV. Our results are relevant for both the QCD axion and axion-like particles (ALPs).

   hep-phastro-ph.COPhys.Dark Univ.(2026)·7 citations
4. 04*

   Structure of non-global logarithms with Cambridge/Aachen clustering

   K. Khelifa-Kerfa🇩🇿

   We determine the structure of both Abelian and non-Abelian non-global logarithms up to four loops for $e^{+}{e}^{-}$ processes in perturbative QCD, where final-state jets are defined using the Cambridge--Aachen (C/A) clustering algorithm. The calculations are performed within the soft (eikonal) approximation using strong-energy ordering of the final-state partons for the case of the dijet invariant mass. The resulting expressions include full colour and complete jet-radius dependence. Compared to the anti-$k_t$ and $k_t$ clustering algorithms, the C/A distribution minimises the impact of these non-global logarithms, making it the preferred choice among the three algorithms.

   hep-phhep-thSciPost Phys.(2026)·2 citations
5. 05*

   Modified TM2 for Reproducing All Best-Fit Values of Neutrino Mixing Angles

   Michael Fodroci🇯🇵 · Teruyuki Kitabayashi🇯🇵

   As measurements of neutrino mixing angles continue to become more precise, it is increasingly likely that in the very near future a realistic neutrino mixing model will be required to precisely reproduce their best-fit values. In this study, a modified TM${}_2$ mixing model which reproduces the best-fit values of all three neutrino mixing angles is proposed. The model reproduces the correct mixing angles within 1$\sigma$ of the current best-fit values and is robust against any future changes of the best-fit values.

   hep-phPTEP(2026)·2 citations
6. 06*

   Large-Width New Physics at Colliders: A Gauge-Invariant Resummation Approach

   Yin-Fa Shen🇺🇸 · Alfredo Gurrola🇺🇸

   Broad resonances challenge the standard Monte-Carlo treatment of unstable particles, which introduces a Breit-Wigner width into leading-order matrix elements and can generate unphysical gauge artifacts. We develop a gauge-consistent framework that combines a Dyson-resummed propagator with Slavnov-Taylor-identity-implied resummed vertices, enabling a consistent implementation in MadGraph5. In the Type-I seesaw model, heavy Majorana neutrinos naturally satisfy $\Gamma \sim m$, leading to strong departures from the Breit-Wigner lineshape, distorted angular correlations, and significant modifications to both $s$- and $t$-channel dynamics. Comparing with the normal and complex-mass schemes, we find that standard treatments can substantially misestimate cross sections and kinematic distributions in the large-width regime. Our results show that existing collider limits on heavy neutrinos-and, more generally, on any broad resonance-should be revisited within a fully resummed framework, opening new opportunities for both experimental searches and theoretical model building.

   hep-ph2 citations
7. 07*

   Potential divergence in tracing $\mu$ and $\tau$ flavors of astrophysical neutrinos

   Zhi-zhong Xing🇨🇳

   We derive general formulas for three flavor fractions $({\eta }_e^{},{\eta }_{\mu }^{},{\eta }_{\tau }^{})$ of the high-energy neutrinos originating from a remote astrophysical source by using their flavor ratios $(f_e^{},f_{\mu }^{},f_{\tau }^{})$ observed at a neutrino telescope, and diagnose a potential divergence associated with ${\eta }_{\mu }^{}$ and ${\eta }_{\tau }^{}$ as an unavoidable consequence of the $\mu$-$\tau$ interchange symmetry exhibiting in the $3\times 3$ lepton flavor mixing matrix $U$. We present a complete set of analytical expressions for $({\eta }_e^{},{\eta }_{\mu }^{},{\eta }_{\tau }^{})$ as functions of two typical $\mu$-$\tau$ symmetry breaking parameters in the standard parametrization of $U$, and apply it to the recent IceCube all-sky neutrino flux data ranging from 5 TeV to 10 PeV in the assumption that the relevant sources have a common flavor composition. We also explain why only ${\eta }_e^{}$ and ${\eta }_{\mu }^{}+{\eta }_{\tau }^{}$ can be extracted from a precision measurement of $f_e^{}$ and $f_{\mu }^{}=f_{\tau }^{}$ in the exact $\mu$-$\tau$ flavor symmetry limit.

   hep-phastro-ph.COastro-ph.HEhep-exNPB(2026)·9 citations
8. 08*

   Towards the full NLO electro-weak corrections to Higgs boson pair production

   Marco Bonetti🇩🇪 · Gudrun Heinrich🇩🇪 · Stephen Jones🇬🇧 · Matthias Kerner🇩🇪 · Philipp Rendler🇩🇪 · Thomas Stone🇬🇧 · Augustin Vestner🇩🇪

   Constraining the Higgs boson self-interaction is one of the main goals for the high luminosity phase of the LHC. A promising channel to this aim is the simultaneous production of two Higgs bosons from gluon fusion. For the interpretation of the data, precise theoretical predictions, also for differential cross sections, are needed. Following current projections this requires electroweak corrections at next-to-leading order. We present the contributions of top-Yukawa and Higgs self-interaction-type, as well as the first steps towards inclusion of the complete NLO electroweak corrections.

   hep-phPoS(2026)·2 citations
9. 09*

   Neutrinoless Double Beta Decay in Light of JUNO First Data

   Shao-Feng Ge🇨🇳 · Chui-Fan Kong🇰🇷 · Manfred Lindner🇩🇪 · João Paulo Pinheiro🇨🇳

   The first results from the JUNO reactor neutrino oscillation experiment improve our knowledge of neutrino masses and mixing parameters, especially the solar angle ${\theta }_s\equiv {\theta }_{12}$ and the solar mass squared difference $\Delta m_s^2\equiv \Delta m_{21}^2$. We discuss the implications of these results on neutrinoless double beta decay by itself and in combination with the global fit of neutrino oscillation experiments, the JUNO first data, and cosmological constraints on the neutrino mass sum. For the effective mass $⟨m_{ee}⟩$, the uncertainties in its lower limits for both mass orderings and upper limits for the normal ordering are largely reduced. Since the cosmological CMB and DESI BAO data put a stringent constraint on the neutrino mass scale, we also show how the probability distribution of both the real and imaginary parts of the effective mass $⟨m_{ee}⟩$ on the complex plane is affected. Especially, the funnel region with $|⟨m_{ee}⟩|\lesssim 1$\,meV receives larger chance to happen. Correspondingly, the chance of determining the two Majorana CP phases simultaneously in this region also increases with reduced uncertainty.

   hep-phhep-exJHEP(2026)·10 citations
10. 10*

    CP Prediction from Residual ${\mathbb{Z}}_2^s$ and ${\overline{\mathbb{Z}}}_2^s$ Symmetries with JUNO First Data

    Shao-Feng Ge🇨🇳 · Chui-Fan Kong🇰🇷 · João Paulo Pinheiro🇨🇳

    The JUNO first data and the recent neutrino global fit results are implemented in the sum rule from the residual ${\mathbb{Z}}_2^s$ and ${\overline{\mathbb{Z}}}_2^s$ symmetries to make prediction of the leptonic Dirac CP phase ${\delta }_D$. Without involving model parameters, the probability distribution of ${\delta }_D$ can be readily obtained from the experimental measurements of the three mixing angles. We then confront the theoretical predictions with the global fit results for the CP phase as well as the T2K and NOvA joint analysis for their CP measurement to give the data preference of the two residual symmetries with Bayes factor for both normal and inverted orderings. We further extend our analysis to a two-dimensional probability distribution to fully explore the correlation between the CP phase ${\delta }_D$ and the atmospheric angle ${\theta }_a\equiv {\theta }_{23}$.

    hep-phhep-exPLB(2026)·11 citations
11. 11*

    Quantum field theory approach to neutrino oscillations in dark matter and implications at JUNO

    Wei Chao🇨🇳

    Neutrino oscillation is a significant physical process worthy of in-depth exploration. In this paper, we investigate the matter effect of massive neutrinos in a scalar-type ultra-light dark matter and calculate the neutrino oscillation probability using the quantum field theory method. The result reveals that the neutrino oscillation probability derived from the quantum field theory approach exhibits no additional time dependence, which marks the most significant distinction from the oscillation result obtained through the quantum mechanics method. Furthermore, we discuss predictions of the Juno experiment regarding neutrino oscillation behavior in scalar-type ultra-light dark matter. This study extends the understanding of the interaction between neutrinos and dark matter, which warrants further exploration.

    hep-ph10 citations
12. 12*

    Partial-Wave Unitarity Bounds on Higher-Dimensional Operators from 2-to-$N$ Scattering

    Céline Degrande🇧🇪 · Hao-Lin Li🇨🇳 · Ling-Xiao Xu🇮🇹

    We present a systematic method for deriving partial-wave unitarity bounds on Wilson coefficients of higher-dimensional operators in effective field theories involving more than four fields, which naturally appear in tree-level 2-to-$N$ scattering processes with $N\ge 3$. Unlike 2-to-2 scattering, 2-to-$N$ scattering with $N\ge 3$ features multiple amplitudes associated with the same total angular momentum. To resolve these degeneracies, we provide a way to construct an orthonormal amplitude basis by parameterizing the phase space manifold of massless particles using spinor-helicity variables, enabling analytical integration over the phase space with arbitrary particle numbers. We provide Mathematica code to analytically evaluate phase space integrals of interference between two local on-shell amplitudes up to four final-state particles, with straightforward generalization to $N$ final-state particles. As practical applications, we demonstrate the use of this tool by deriving unitarity bounds on some dimension-7 and dimension-8 operators in the Standard Model effective field theory involving five and six fields, respectively.

    hep-ph5 citations
13. 13*

    Probing unitarity violation of lepton flavor mixing matrix with reactor antineutrinos at JUNO and TAO

    Jihong Huang🇨🇳 · Shun Zhou🇨🇳

    Motivated by the precise measurements of neutrino oscillation parameters at Jiangmen Underground Neutrino Observatory (JUNO), we investigate the possibility of probing the unitarity violation of lepton flavor mixing matrix solely with reactor antineutrinos. First, we stress that it is necessary to reconsider the production and detection of neutrinos in a self-consistent way, apart from neutrino propagation, when analyzing experimental sensitivities to unitarity violation. Then, concentrating on JUNO and its satellite experiment Taishan Antineutrino Observatory (TAO), we demonstrate how the event rates of inverse beta decays (i.e., ${\overline{\nu }}_e^{}+p\to e^{+}+n$) for observing ${\overline{\nu }}_e^{}\to {\overline{\nu }}_e^{}$ oscillations, and those of elastic antineutrino-electron scattering (i.e., ${\overline{\nu }}_{\alpha }^{}+e^{-}\to {\overline{\nu }}_{\alpha }^{}+e^{-}$ with $\alpha =e,\mu ,\tau$) for ${\overline{\nu }}_e^{}\to {\overline{\nu }}_{\mu }^{}$ and ${\overline{\nu }}_e^{}\to {\overline{\nu }}_{\tau }^{}$ oscillations, depend on the parameters characterizing unitarity violation. Our investigation will be useful for JUNO and TAO to place independent constraints with more data in the near future.

    hep-phhep-exPLB(2026)·17 citations
14. 14*

    Assessing (H)EFT theory errors by pitting EoM against Field Redefinitions

    Rodrigo Alonso🇬🇧 · Christoph Englert🇬🇧 · Wrishik Naskar🇩🇪 · Shakeel Ur Rahaman🇬🇧

    Truncations of effective field theory expansions are technically necessary but inherently intertwined with the redundancies of general field redefinitions. This can be viewed as a juxtaposition of power-counting and theoretical uncertainties, which seek to estimate neglected higher-dimensional interactions through approaches based on community consensus. One can then understand the invariance of physics under field redefinitions as a data-informed validation of different power-counting schemes, or as a means of assigning theoretical errors in comparison with algebraic, equation of motion-based replacements. Such an approach generalises widely accepted procedures for estimating theoretical uncertainties within the SM to non-renormalisable interactions. We perform a case study for a representative example in Higgs Effective Field theory, focusing on universal Higgs properties tensioned against process-dependent sensitivity expectations.

    hep-phhep-exJHEP(2026)·4 citations
15. 15*

    Towards the LHCb pentaquark modes in the single-charm sector

    Chao-Wei Shen🇨🇳 · Yong-Hui Lin🇩🇪 · Hao-Jie Jing🇨🇳

    The mass spectrum of ${\Lambda }_c$ baryon family is investigated within the $DN$-$D^{\ast }N$ coupled-channel framework using two phenomenological approaches for the low-energy $D^{(\ast )}N$ interactions: the heavy quark effective theory and the flavor-symmetry-constrained effective Lagrangian method. It is shown that the LHCb pentaquark states have direct analogs in the ${\Lambda }_c$ family. Specifically, ${\Lambda }_c(2765)$, ${\Lambda }_c(2910)$, and ${\Lambda }_c(2940)$ mirror the patterns of $P_{c\bar{c}}(4312)$, $P_{c\bar{c}}(4440)$, and $P_{c\bar{c}}(4457)$, respectively. These mirror pentaquark modes offer valuable insights into the quantum numbers of the two heavy $P_{c\bar{c}}$ states, which remain experimentally undetermined. Further exploration of such correlations among exotic hadronic states across different flavor sectors will be crucial for developing a comprehensive theoretical understanding of the modern hadron spectrum.

    hep-ph2 citations
16. 16*

    Trimaximal Mixing Patterns Meet the First JUNO Result

    Di Zhang🇩🇪

    The JUNO experiment has recently released its first measurement results based on 59.1 days of data, achieving unprecedented precision in measuring the lepton mixing angle ${\theta }_{12}$. This significant improvement places stringent constraints on certain neutrino mass models and flavor mixing patterns. In this work, we examine the impact of the latest JUNO results on the two trimaximal (i.e., TM1 and TM2) mixing patterns. They are two well-motivated variants of the tri-bimaximal mixing pattern and predict specific correlations between ${\theta }_{12}$ and ${\theta }_{13}$. After taking into account the first JUNO results, the TM1 mixing pattern sits on the edge of the experimentally allowed $1\sigma$ region, while the TM2 mixing pattern lies outside the $3\sigma$ region. To reconcile these TM mixing patterns with the latest experimental data, we further investigate the renormalization group (RG) running effects on them in the both Majorana and Dirac neutrino cases. Our analytical and numerical results show that RG corrections can bring the two TM mixing patterns into excellent agreement with the latest JUNO data if neutrino masses are quasi-degenerate. However, the Majorana case faces severe constraints from neutrinoless double beta decay limits, and particularly, the TM2 mixing pattern with Majorana neutrinos has been essentially ruled out. In the Dirac case, the TM1 mixing pattern is fully consistent with current data including beta decay results, whereas the TM2 pattern is strongly constrained by the KATRIN limit and even could be largely ruled out if the KATRIN experiment reaches its final sensitivity without any discovery. Future high-precision measurements of lepton mixing parameters and absolute neutrino masses in both oscillation and non-oscillation experiments will provide decisive tests of these mixing patterns.

    hep-phhep-exPRD(2026)·19 citations
17. 17*

    New features in the Z2xZ2 3HDM two component DM model

    Jorge C. Romão🇵🇹 · Rafael Boto🇵🇹 · Pedro N. Figueiredo🇵🇹 · João P. Silva🇵🇹

    We investigate the constraints and phenomenology of a three Higgs doublet model (3HDM) with a $\mathbb{Z}2\times \mathbb{Z}2$ symmetry, featuring two inert scalar doublets that give rise to a two-component dark matter (DM) scenario. We analyze the model's vacuum structure, exploring the competition between different symmetry-breaking minima, and subject it to comprehensive theoretical and current experimental constraints. Our analysis reveals previously unexplored regions of parameter space with viable dark matter candidates. Notably, we identify scenarios where both DM particles contribute comparably to the observed relic density, offering distinctive experimental signatures that could guide future searches.

    hep-phMod.Phys.Lett.A(2026)·1 citation
18. 18*

    Fantômas: An analysis of parton distributions in a pion with Bézier parametrizations

    Lucas Kotz🇺🇸 · Aurore Courtoy🇲🇽 · Pavel Nadolsky🇺🇸 · Fredrick Olness🇺🇸 · Maximiliano Ponce-Chavez🇺🇸

    We systematically explore the parametrization dependence of the Parton Distribution Functions (PDFs) to better quantify the true uncertainty from global QCD analyses. To achieve this, we employ a novel technique that automates the generation of polynomial parametrizations for PDFs using Bézier curves. This technique is implemented in a C++ module, named Fantômas, which is now included within the xFitter program. As an example, we examine the charged pion PDF. Our analysis reveals that the sea and gluon distributions in the pion are strongly correlated, and PDF solutions featuring a vanishing gluon and a large quark sea are still experimentally allowed.

    hep-phPoS(2025)·0 citations
19. 19*

    Bridging the Gap: Connecting Atomic Nuclei to Their Quantum Foundations

    Fredrick Olness🇺🇸

    We extend the QCD Parton Model analysis by employing a factorized nuclear structure model that explicitly accounts for both individual nucleons and correlated nucleon pairs. This novel framework establishes a paradigm that directly links the nuclear physics description of matter (in terms of protons and neutrons) to the particle physics schema (in terms of quarks and gluons). Our analysis of high-energy data from lepton Deep-Inelastic Scattering, Drell-Yan, and W/Z production simultaneously extracts the universal effective distribution of quarks and gluons inside correlated nucleon pairs, and their nucleus-specific fractions. The successful extraction of these universal distributions marks a significant advance in our understanding of nuclear structure, as it directly connects nucleon-level and parton-level quantities.

    hep-phnucl-thPoS(2025)·0 citations
20. 20*

    Further Reduction of the PDF Uncertainty in the High-Mass Drell-Yan Spectrum Utilizing Neutral and Charged Current Inputs

    Yao Fu🇺🇸 · Raymond Brock🇺🇸 · Daniel Hayden🇺🇸 · Chien-Peng Yuan🇺🇸

    Uncertainties in the parametrization of Parton Distribution Functions are a serious limiting systematic uncertainty in Large Hadron Collider searches for Beyond the Standard Model physics. This is especially true for measurements at high scales induced by quark and anti-quark collisions, where Drell-Yan continuum backgrounds are dominant. In Phys. Rev. D99, 054004 (2019) we presented a unique strategy for improving uncertainties using neutral current Drell-Yan backgrounds and here we update that strategy and include charged current Drell-Yan final states in the program and demonstrate significant improvements. Through a judicious selection of measurable kinematical quantities can reduce the assigned systematic PDF uncertainties by significant factors in limit-setting or discovery for neutral and charged, high mass Intermediate Vector Bosons. This approach will be take advantage of the huge statistical precision of future High Luminosity, Large Hadron Collider Standard Model datasets and could also improve uncertainties in the high statistics results from LHC Run 3.

    hep-ph3 citations
21. 21*

    Terrestrial Matter Effects on Reactor Antineutrino Oscillations: Constant vs. Fluctuated Density Profiles

    Yu-Feng Li🇨🇳 · Andong Wang🇨🇳 · Ya Xu🇨🇳 · Jing-yu Zhu🇨🇳

    The JUNO Collaboration has recently released its first reactor antineutrino oscillation result, achieving unprecedented precision in the measurement of $\Delta m_{21}^2$ and ${\sin }^2{\theta }_{12}$. We emphasize that the accurate determination and modeling of the terrestrial matter density profile are fundamental for extracting the oscillation parameters and probing the neutrino mass ordering. This paper presents a realistic piecewise-constant model for the shallow crustal density profile along the baselines from Taishan and Yangjiang to the experimental hall, based on geological and petrophysical information. The uncertainty in the density profiles arises from variations in the density and length of each segment, both of which are conservatively estimated to be 10%. A careful comparison of constant and fluctuated density profiles is provided and the implications for the precision measurement of oscillation parameters are discussed. Finally, we also discuss the prospect of shallow crust tomography in future reactor neutrino experiments.

    hep-phJHEP(2026)·11 citations
22. 22*

    Resolving Ratio Redundancy in Chemical Freeze-out Studies with Principal Component Analysis and Bayesian Calibration

    Nachiketa Sarkar🇮🇳

    We introduce a Principal Component Analysis (PCA)--Bayesian framework for extracting chemical freeze-out conditions in relativistic heavy-ion collisions that resolves long-standing ambiguities in hadron-ratio--based analyses. By constructing all possible hadron-yield ratios from a chosen set of species and transforming them into an orthogonal PCA basis, the method removes linear redundancies and eliminates the information loss and systematic uncertainties associated with ratio selection. Energy-wise Bayesian calibration of the Hadron Resonance Gas (HRG) model is then performed directly in this decorrelated space, with a Gaussian Process emulator enabling fast and accurate model evaluations. A detailed Sobol sensitivity analysis, together with the PCA loading structure, identifies the most informative ratio combinations and reveals a transition from chemical-potential--dominated to temperature-controlled freeze-out with increasing $\sqrt{s_{NN}}$. The calibrated model reproduces all measured ratios, and the extracted freeze-out parameters are consistent with previous HRG determinations.

    hep-phnucl-th0 citations
23. 23*

    SURFing to the Fundamental Limit of Jet Tagging

    Ian Pang🇺🇸 · Darius A. Faroughy🇺🇸 · David Shih🇺🇸 · Ranit Das🇺🇸 · Gregor Kasieczka🇩🇪

    Beyond the practical goal of improving search and measurement sensitivity through better jet tagging algorithms, there is a deeper question: what are their upper performance limits? Generative surrogate models with learned likelihood functions offer a new approach to this problem, provided the surrogate correctly captures the underlying data distribution. In this work, we introduce the SUrrogate ReFerence (SURF) method, a new approach to validating generative models. This framework enables exact Neyman-Pearson tests by training the target model on samples from another tractable surrogate, which is itself trained on real data. We argue that the EPiC-FM generative model is a valid surrogate reference for JetClass jets and apply SURF to show that modern jet taggers may already be operating close to the true statistical limit. By contrast, we find that autoregressive GPT models unphysically exaggerate top vs. QCD separation power encoded in the surrogate reference, implying that they are giving a misleading picture of the fundamental limit.

    hep-phcs.LGhep-exphysics.data-an4 citations
24. 24*

    The Heavy Dark Photon Handbook: Cosmological and Astrophysical Bounds

    Andrea Caputo🇨🇭 · Jaeyoung Park🇨🇭 · Seokhoon Yun🇰🇷

    We investigate cosmological and astrophysical constraints on dark photons with masses $\sim 10^{-1}$-$10^3$ MeV. These dark photons can be copiously produced either in the early universe or during core-collapse supernovae, potentially leaving distinct observational signatures. First, we derive updated constraints from cosmological and astrophysical observables that rely on the thermal relic abundance of dark photons, including the CMB spectrum, primordial light element abundances, and galactic/extragalactic gamma-ray flux. We consider the minimal reheating temperature possible, $T_{\mathrm{RH}}=6\mathrm{MeV}$, such that our constraints are conservative, but unavoidable within the minimal dark photon model. Then, for supernova-sourced dark photons, we systematically examine all relevant observational bounds, revisit the standard cooling argument and derive limits from other arguments such as fireball formation, low energy supernovae and galactic positron injection.

    hep-phPRD(2026)·28 citations
25. 25*

    How light can ALP dark matter be?

    Kierthika Chathirathas🇩🇪 · Thomas Schwetz🇩🇪

    We assume axion-like particles (ALPs) to provide the full dark matter abundance and derive various lower bounds on the ALP mass. We contrast the post- and pre-inflationary symmetry breaking cases and present allowed regions in the plane of ALP mass and energy scale of inflation. For the post-inflationary case, we revisit bounds from isocurvature perturbations taking into account that, as suggested by simulations, axion radiation by cosmic strings during the scaling regime provides the dominant production mechanism of dark matter, obtaining significantly weaker limits than previously. Combining isocurvature, with constraints from black hole superradiance and free streaming, we find that the bound $m_a\gtrsim 10^{-17}$ eV applies for most cases considered here. It can be potentially relaxed to $\sim 6\times 10^{-19}$ eV only in the post-inflationary case with a strongly temperature-dependent axion mass, subject to uncertainties on the axion emission spectrum. Significantly stronger bounds are obtained in the post-inflationary scenario from the non-observation of CMB tensor modes, which can be as strong as $m_a>5\times 10^{-7}$ eV for small reheating efficiencies, $ϵ\lesssim 5\times 10^{-4}$.

    hep-phastro-ph.COJCAP(2026)·6 citations
26. 26*

    Axiverse Baryogenesis

    Pouya Asadi🇺🇸 · David Cyncynates🇺🇸 · Stefania Gori🇺🇸

    The QCD axion may offer a unified origin for the baryon asymmetry and dark matter through axiogenesis. However, in the minimal QCD axion scenario, axiogenesis either underproduces baryons or overproduces dark matter, and the required kinetic misalignment initial conditions are in tension with axion quality. In this \textit{Letter}, we demonstrate that the axiverse naturally resolves these tensions: the QCD axion emerges as a linear combination of multiple axion-like fields, evading the overclosure problem thanks to new dissipation channels , while introducing additional Peccei--Quinn symmetries that ensure a high quality QCD axion. We illustrate these points in a toy model with two axions. This framework predicts a rich phenomenology within experimental reach, including dark matter detection prospects, astrophysical signals, and collider signatures.

    hep-ph6 citations
27. 27*

    Constraints on lepton-flavor mixing with third-generation new physics

    Sebastiano Covone🇨🇭 · Pol Morell🇪🇸 · Arianna Tinari🇨🇭

    We study the implications of an approximate $U(2{)}^5$ flavor symmetry at the TeV scale, under the assumption of new physics predominantly coupled to the third-generation fermions, focusing on the breaking of the $U(2{)}_{\ell }$ subgroup governing the mixing between second- and third-generation left-handed leptons. We derive constraints on the corresponding spurion parameter $\delta$ from current data on lepton flavor violating (LFV) and lepton flavor universality (LFU) observables, finding that $R_{K^{(\ast )}}$ and $\mathcal{B}(B_s\to \mu \mu )$ give the most stringent bound on $\delta$, yielding $|\delta |<0.051$ at 95% CL. In addition, we provide updated bounds for LFV decay rates and discuss prospects for future sensitivity improvements, finding that future LFV searches could further tighten constraints on the mixing between second- and third-generation leptons.

    hep-phPLB(2026)·6 citations
28. 28*

    The Penrose Transform and the Kerr-Schild double copy

    Emma Albertini🇮🇹 · Michael L. Graesser🇺🇸 · Gabriel Herczeg🇺🇸

    There are a number of classical double copies, each providing a prescription for generating solutions to the Maxwell and scalar wave equations from exact solutions of Einstein's equations. Two such prescriptions are the Kerr-Schild and twistorial double copies. We argue that for a broad class of self-dual vacuum solutions of the Kerr-Schild form, which we refer to as twistorial Kerr-Schild spacetimes, these two prescriptions are in fact equivalent. The approach is elementary, utilizing null Lorentz transformations, with homogenous functions on twistor space playing a central role. The equivalence is illustrated explicitly for the example of the self-dual (Kerr)-Taub-NUT spacetime. A detailed proof and several more examples will be presented in a long-form companion to this letter.

    ↳ hep-thgr-qchep-ph4 citations
29. 29*

    Sampling Polynomial Rational Remainders with SP$\mathbb{Q}$R: A new Package for Polynomial Division and Elimination

    Vsevolod Chestnov🇮🇹 · Giulio Crisanti🇬🇧

    We introduce SP$\mathbb{Q}$R, a new Mathematica package for the division and elimination of variables from polynomial systems. SP$\mathbb{Q}$R works by sampling and reconstructing results over finite fields, in an analogous manner to many state of the art Integration by Parts algorithms for Feynman integrals. This allows SP$\mathbb{Q}$R to effectively overcome expression swell during the construction of Gröbner bases, which in many cases is the major bottleneck in such computations. Benchmarks on state of the art Macaulay resultants show that SP$\mathbb{Q}$R can deliver substantial gains over symbolic computer algebra workflows -- reducing both runtime and memory footprint by multiple orders of magnitude. Likewise when applied to study Feynman integrals, we show how SP$\mathbb{Q}$R can be used to find previously unknown Landau singularities.

    ↳ hep-thhep-phmath-phmath.MP5 citations
30. 30*

    New algorithms for Feynman integral reduction and $\epsilon$-factorised differential equations

    Iris Bree🇩🇪 · Federico Gasparotto🇩🇪 · Antonela Matijašić🇩🇪 · Pouria Mazloumi🇩🇪 · Dmytro Melnichenko🇩🇪 · Sebastian Pögel🇨🇭 · Toni Teschke🇩🇪 · Xing Wang🇨🇳 · Stefan Weinzierl🇩🇪 · Konglong Wu🇨🇳 · Xiaofeng Xu🇨🇳

    In this paper, we give a detailed account of the algorithm outlined in [1] for Feynman integral reduction and $\epsilon$-factorised differential equations. The algorithm consists of two steps. In the first step, we use a new geometric order relation in the integration-by-parts reduction to obtain a basis of master integrals, whose differential equations on the maximal cut are of a Laurent polynomial form in the regularisation parameter $\epsilon$ and compatible with a filtration. This step works entirely with rational functions. In a second step, we provide a method to $\epsilon$-factorise the aforementioned Laurent differential equations. The second step may introduce algebraic and transcendental functions. We illustrate the versatility of the algorithm by applying it to different examples with a wide range of complexity.

    ↳ hep-thhep-phmath-phmath.MPPRD(2026)·24 citations
31. 31*

    Viscous Dark Energy and Mass-Varying Dark Matter in Lyra Manifold: Cosmological Dynamics and Observational Constraints

    Giridhari Deogharia🇮🇳 · Madhurima Pandey🇮🇳 · Ashadul Halder🇮🇳

    We investigate the cosmological dynamics of a universe described by Lyra's geometry in the presence of dark energy (DE) and dark matter (DM). Dark energy is modeled as a quintessence scalar field with bulk viscosity, while dark matter is allowed to interact with the scalar sector. The displacement vector field, arising naturally in Lyra's manifold, provides an additional geometric contribution. By employing dynamical system techniques, we analyze stability properties and late-time attractors. Our results indicate that viscosity and DE--DM interaction enrich the phase space structure and can help address both the cosmic acceleration and the coincidence problem. Furthermore, by performing a Markov Chain Monte Carlo (MCMC) analysis with recent observational datasets, we derive best-fit values for the model parameters that exhibit good consistency with current data.

    ↳ astro-ph.COgr-qchep-ph1 citation
32. 32*

    Detectability of axion-like dark matter for different time-delay interferometry combinations in space-based gravitational wave detectors

    Yong-Yong Liu🇨🇳 · Jing-Rui Zhang🇨🇳 · Ming-Hui Du🇨🇳 · He-Shan Liu🇨🇳 · Peng Xu🇨🇳 · Yun-Long Zhang🇨🇳

    In the space-based gravitational wave detections, the axion-like dark matter would alter the polarization state of the laser link between spacecrafts due to the birefringence effect. However, current designs of space-based laser interferometer are insensitive to variations in the polarization angle. Thus, the additional wave plates are employed to enable the response of the axion-induced birefringence effect. We calculate and compare the sensitivities of different space-based detectors, accounting for three time-delay interferometry combinations, including Monitor, Beacon, and Relay. We find that the Monitor and Beacon combinations have better sensitivity in the high-frequency range, and the optimal sensitivity reaches $g_{a\gamma }\sim 10^{-13}{\text{GeV}}^{-1}$, while the Sagnac combination is superior in the low-frequency range. We also find that ASTROD-GW can cover the detection range of axion-like dark matter mass down to $10^{-20}\text{eV}$.

    ↳ gr-qcastro-ph.COhep-phEPJC(2026)·5 citations
33. 33*

    First observation of deuteron-{\Lambda} correlations at RHIC

    STAR Collaboration

    Precise experimental information on hyperon-nucleon interactions is scarce but of paramount importance to our understanding of the inner structure of compact stars. In this letter, we report the first experimental results of correlation functions between deuterons (d) and {\Lambda} hyperons in Au+Au collisions at \sqrt{s_{NN} = 3.0 GeV measured by the STAR experiment at RHIC. A clear enhancement at small relative momenta has been observed in the correlation function. Through a Bayesian inference analysis, the source size parameters as a function of collision centrality and the spin- dependent strong interaction parameters (scattering length f0 and effective range d0) are extracted using the Lednický-Lyuboshitz formalism. The derived doublet spin state parameters (f0, d0) lead to a novel method to precisely determine {\Lambda} separation energy for the weakly bounded hypertriton ^{3}_{{\Lambda}}H.

    ↳ nucl-exhep-phnucl-thPRL(2026)·10 citations
34. 34*

    Is There New Physics Beyond 30 TeV in the BOAT?

    Filip Rescic🇪🇸 · Luis Recabarren Vergara🇮🇹 · Michele Doro🇮🇹 · Tomislav Terzić🇭🇷

    We show that the GRB 221009A spectrum detected by LHAASO can be used to probe effects of quadratic subluminal Lorentz Invariance Violation (LIV) through the enhancement of the observed flux at the highest energies. In particular, we argue that excesses in the GRB 221009A data currently classified as non-detections at energies $E\gtrsim 30$ TeV warrant further investigation, as they may indicate a recovery of the intrinsic source spectrum consistent with the LIV-induced suppression of $\gamma \gamma \to e^{-}{e}^{+}$ interactions within the quadratic subluminal scenario. This would increase the accessible parameter space of the energy scale of new physics.

    ↳ astro-ph.HEhep-phPhys.Dark Univ.(2026)·0 citations
35. 35*

    Extracting Mellin moments of double parton distributions from lattice data

    Markus Diehl🇩🇪 · Oskar Grocholski🇩🇪 · Daniel Reitinger🇩🇪 · Andreas Schäfer🇩🇪 · Christian Zimmermann🇺🇸

    Reconstructing Mellin moments of double parton distributions from calculations on a Euclidean lattice requires taking an integral over a variable that may be regarded as a Ioffe time. The Fourier conjugate of this variable plays the role of a kinematic skewness in the double parton distributions. We discuss the skewness dependence of the relevant hadronic correlation functions. Using several models, we study the impact of this dependence on extracting moments of double parton distributions from existing lattice data.

    ↳ hep-lathep-phJHEP(2026)·1 citation
36. 36*

    Relativistic mean-field model with density- and isospin-density-dependent couplings

    Gabriel Frohaug🇺🇸 · Konstantin Maslov🇺🇸 · Veronica Dexheimer🇺🇸 · Joaquin Grefa🇺🇸 · Johannes Jahan🇺🇸 · Claudia Ratti🇺🇸 · Tulio E. Restrepo🇺🇸

    We present a new hadronic EoS with hyperons built within the relativistic mean-field (RMF) formalism with baryon-density- and isospin-density-dependent couplings. Motivated by microscopic calculations showing density- and isospin-asymmetry-dependence of self-energies, we implement a new form for the baryon-meson couplings. The parameters for the couplings are constrained by a Bayesian analysis, which anchors the model to nuclear saturation properties, chiral effective field theory ($\chi$EFT) predictions for pure neutron matter, heavy-ion collision data, and HALQCD-based hyperon potential calculations at 3-momentum $|\mathbf{k}|=0$ in both isospin-symmetric and pure neutron matter. The resulting EoS satisfies neutron star mass-radius constraints from NICER and GW170817, providing another way to address the hyperon puzzle. The low-density part of the EoS is described via nuclear statistical equilibrium with modern mass tables (AME20/FRDM12, 8244 nuclei), providing a novel and complete general-purpose EoS for astrophysical simulations.

    ↳ nucl-thastro-ph.HEhep-phPRD(2026)·5 citations
37. 37*

    From Qubits to Couplings: A Hybrid Quantum Machine Learning Framework for LHC Physics

    Marwan Ait Haddou🇲🇦 · Mohamed Belfkir🇦🇪 · Salah Eddine El Harrauss🇦🇪

    In this paper, we propose a new Hybrid Quantum Machine Learning (HyQML) framework to improve the sensitivity of double Higgs boson searches in the $HH\to b\bar{b}\gamma \gamma$ final state at $\sqrt{s}$ = 13.6 TeV. The proposed model combines parameterized quantum circuits with a classical neural network meta-model, enabling event-level features to be embedded in a quantum feature space while maintaining the optimization stability of classical learning. The hybrid model outperforms both a state-of-the-art XGBoost model and a purely quantum implementation by a factor of two, achieving an expected 95% CL upper limit on the non-resonant double Higgs boson production cross-section of $1.9\times {\sigma }_{\text{SM}}$ and $2.1\times {\sigma }_{\text{SM}}$ under background normalization uncertainties of 10% and 50%, respectively. In addition, expected constraints on the Higgs boson self-coupling ${\kappa }_{\lambda }$ and quartic vector-boson-Higgs coupling ${\kappa }_{2V}$ are found to be improved compared to the classical and purely quantum models.

    ↳ hep-exhep-phPTEP(2026)·1 citation
38. 38*

    Impact of cosmic expansion on gravitational wave spectra from strongly supercooled first-order phase transitions

    Marek Lewicki🇵🇱 · Ville Vaskonen🇮🇹

    We compute the gravitational wave spectra from strongly supercooled first-order phase transitions, explicitly incorporating the evolution of the background metric across the transition from thermal inflation to radiation domination. We find that the spectral shape remains largely unchanged apart from a causality-induced super-horizon tail. However, in contrast to standard expectations, for slow transitions we show that the peak amplitude and frequency exhibit a weaker dependence on the transition rate $\beta$ than the usual scaling of $\propto {\beta }^{-2}$ and $\propto \beta$, respectively.

    ↳ astro-ph.COhep-phPhys.Dark Univ.(2026)·12 citations
39. 39*

    Effects of short-range correlations at high densities on neutron stars with and without DM content: role of the repulsive self-interaction

    Odilon Lourenço🇧🇷 · Everson H. Rodrigues🇧🇷 · Carline Biesdorf🇪🇸 · Mariana Dutra🇧🇷

    In this work, we investigate how short-range correlations affect relativistic hadronic models at high densities, with direct consequences for the structure of neutron stars, both with and without dark matter content. Two versions of the model are examined: one with vector self-interactions up to second order (${\omega }_0^2$) and another including a fourth-order term (${\omega }_0^4$). We show that SRC tend to soften the equation of state when only the quadratic term is present, but produce a noticeable stiffening once the ${\omega }_0^4$ term is included. The corresponding Tolman-Oppenheimer-Volkoff solutions for pure neutron stars indicate that short-range correlations reduce the maximum mass in the first case but increase it in the second. Extending the analysis to stars containing a fermionic dark matter component, within the two-fluid formalism, we verify that the same features appear in the respective mass-radius diagrams. In particular, the decrease of the maximum mass with increasing dark matter fraction is partly compensated by the SRC effects in the hadronic sector for the model with the fourth-order term. In all cases, the resulting parametrizations are consistent with recent astrophysical constraints, including the joint NICER-XMM-Newton analyses of the pulsars PSR J0030+0451 and PSR J0740+6620, as well as the gravitational-wave event GW190425.

    ↳ nucl-thhep-phPRD(2026)·2 citations
40. 40*

    Holographic Constraints on the String Landscape

    Alek Bedroya🇺🇸 · Paul J. Steinhardt🇺🇸

    We show that holography imposes strong and general constraints on scalar field potentials in the string landscape, determined by the asymptotic structure of the underlying spacetime. Applying these holographic consistency conditions, we identify broad classes of scalar potentials that are incompatible with a well-defined dual description. These include potentials with extended plateaus, excessively steep or shallow asymptotics, certain zero crossings, and specific alignments of stable AdS minima in moduli space. In particular, making the standard assumption that the CFT dual to a stable AdS vacuum must be realized as a worldvolume theory of a brane in string theory, we show that the brane selects an infinite-distance limit in moduli space where parametric scale separation is forbidden. Furthermore, the steepness and positivity of the potential are restricted in that infinite distance direction. We also find that requiring the validity of the effective theory in the future vacuum, a natural holographic criterion, automatically enforces the Trans-Planckian Censorship Conjecture (TCC) for classical cosmological solutions with positive potentials. Taken together, these constraints exclude the leading proposals to realize scale-separated AdS vacua and metastable de Sitter vacua in the string theory landscape such as DGKT and KKLT.

    ↳ hep-thastro-ph.COgr-qchep-ph7 citations
41. 41*

    How Bright in Gravitational Waves are Millisecond Pulsars for the Galactic Center GeV Gamma-Ray Excess? A Systematic Study and Implications for Dark Matter

    Ming-Yu Lei🇨🇳 · Bei Zhou🇺🇸 · Xiaoyuan Huang🇨🇳

    The existence of dark matter (DM) is supported by various macroscopic observations, but its microscopic nature remains elusive. The Galactic Center GeV gamma-ray excess (GCE) has been a leading candidate signal for particle DM annihilation. However, an unresolved population of millisecond pulsars (MSPs) in the bulge provides the alternative explanation for the excess. Identifying these MSPs in electromagnetic bands is difficult due to source confusion, pulse broadening, and extinction. Gravitational waves (GWs) provide a complementary probe: a steadily rotating, non-axisymmetric MSP emits a nearly monochromatic GW signal in the sensitive band of ground-based detectors, with amplitude set by its ellipticity. In this work, we systematically investigate the GW emission from the MSP population proposed to explain the GCE and its detectability with current and future detectors. We consider three major scenarios for the origin of ellipticity and model the population properties of these MSPs. We also consider both isolated MSPs and MSPs in binary systems, as well as Doppler effects in the detection. We find that while the signal is below the reach of current interferometers, next-generation detectors such as the Einstein Telescope (ET) and Cosmic Explorer (CE) may detect a fraction of those MSPs, offering a novel test of the MSP interpretation of the GCE. Future directed searches toward the Galactic Center with continued improvements in sensitivities will either uncover this long-sought MSP population or place stringent limits on their ellipticities and abundance, with important implications for both the astrophysical and DM interpretations of the GCE.

    ↳ astro-ph.HEgr-qchep-exhep-ph4 citations
42. 42*

    The Noisy Universe

    Gabriela Barenboim🇪🇸 · Aurora Ireland🇺🇸 · Albert Stebbins🇺🇸

    We present observational constraints on large-scale white noise (LSWN) in the cosmic density field, a phenomenon predicted to arise from non-linear mode coupling during cosmological evolution. Building on the theoretical framework of Paper I, where we demonstrated that non-linearities inevitably redistribute power from small to large scales through mode mixing, we confront these predictions with current cosmological data. We modify the CLASS Boltzmann code to incorporate a white noise component $k_{\mathrm{BH}}/k$ in the primordial power spectrum and perform parameter estimation using current cosmological data. The non-detection of excess power on the largest observable scales places stringent upper bounds: $k_{\mathrm{BH}}\le 1.80\times 10^{-13}{\mathrm{Mpc}}^{-1}$ at 99\% confidence. These constraints imply the primordial power spectrum must deviate from perfect scale invariance on small scales, either through a cutoff at $k_{\mathrm{cut}}\lesssim 3{\mathrm{pc}}^{-1}$ or through running of the spectral index with ${\alpha }_s\lesssim -0.015$. Our results demonstrate that LSWN provides a powerful probe of the primordial spectrum at scales orders of magnitude smaller than directly observable, offering unique constraints on early-universe physics.

    ↳ astro-ph.COgr-qchep-phPRL(2026)·6 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.