Tue·Jun 17, 2025Tuesday·June 17, 2025

1. 01*

   Hunting for Dark Photon-Photon Tridents

   Thong T.Q. Nguyen🇸🇪

   Dark photons, hypothesized to be sufficiently light and/or weakly interacting, offer a compelling candidate for dark matter. Their decay into three photons, referred to as the "dark photon trident" process, becomes the dominant channel when the dark photon mass lies below the electron pair production threshold. This decay channel produces a significant flux of x-rays, presenting an opportunity for indirect detection. In this study, we analyze 16 years of x-ray data from INTEGRAL/SPI to investigate sub-MeV dark photon decay. By incorporating state-of-the-art astrophysical background modeling and accounting for the full one-loop decay amplitude, we achieve world-leading constraints on the kinetic mixing parameter for dark photon masses in the range of 61-1022 keV. These results represent a significant improvement over previous constraints, narrowing the parameter space for viable dark photon dark matter models. Furthermore, our findings highlight the potential of x-ray observatories to probe unexplored regions of parameter space and pave the way for future searches using next-generation instruments designed to detect faint astrophysical signals.

   hep-phastro-ph.HEPoS(2025)·6 citations
2. 02*

   Four-Loop Renormalisation of Chiral Gauge Theories with Non-Anticommuting ${\gamma }_5$ in the BMHV Scheme

   Andreas von Manteuffel🇩🇪 · Dominik Stöckinger🇩🇪 · Matthias Weißwange🇩🇪

   We present the complete 4-loop renormalisation of an Abelian chiral gauge theory in the Breitenlohner-Maison / `t Hooft-Veltman (BMHV) scheme. Employing a non-anticommuting ${\gamma }_5$ in dimensional regularisation, we determine the full set of symmetry restoring counterterms from the quantum action principle. Our calculation represents the highest-order application of the BMHV framework so far, pushing the limits of a self-consistent treatment of ${\gamma }_5$ at the multi-loop level. We describe the computational setup that we developed to perform the computations and discuss key implementation aspects, such as the BMHV algebra and tensor reduction. Our work demonstrates the feasibility of applying the BMHV scheme at high loop orders and establishes a solid foundation for future studies of high-precision electroweak physics.

   hep-phhep-thJHEP(2025)·14 citations
3. 03*

   Study of anisotropic flow of heavy hadrons in Au + Au collisions at $\sqrt{s_{NN}}=$ 200 GeV using HYDJET++ framework

   Sunidhi Saxena🇮🇳 · Gauri Devi🇮🇳 · Rajiv Gupta🇮🇳 · Ajay Kumar🇮🇳

   A comprehensive study of the anisotropic flow of heavy hadrons ($D^0$, $D^{\pm }$, and ${\Lambda }_c$) in Au + Au collisions at $\sqrt{s_{NN}}=200$ GeV using the HYDJET++ model is presented. This study aims to explore the collective behavior and thermalization of charm hadrons at RHIC energy. The modeling of anisotropic flow is performed using a centrality-dependent parameterization of anisotropic parameters. Our model results are consistent with STAR experimental results up to $p_T=4$ GeV/c. It captures the centrality-dependent shifts of the flow peak towards lower $p_T$ as collisions become more peripheral. This shift is attributed to the weaker radial flow in peripheral collisions. The model also reproduces important features such as the number-of-constituent-quark scaling, mass ordering, and baryon-meson grouping, all consistent with experimental observations. Furthermore, we present comparisons with other models, like DUKE, SUBATECH, TAMU, and AMPT. Overall, our results highlight the efficacy of HYDJET++ in describing the collective dynamics of heavy-flavor hadrons in the quark-gluon plasma medium.

   hep-ph1 citation
4. 04*

   Impact on $L$-observables of a new combined analysis of $B_{d,s}\to K^{(\ast )}$ form factors

   Aritra Biswas🇩🇪 · Nico Gubernari🇬🇧 · Joaquim Matias🇪🇸 · Gilberto Tetlalmatzi-Xolocotzi🇩🇪

   We explore the impact of a combined analysis of $B_{d,s}\to K^{(\ast )}$ form factors on a set of $L$-observables. The $L$-observables are constructed from ratios of branching fractions in $B_s\to VV,PP,PV$ versus $B_d\to VV,PP,PV$ decays with $P=K^0,{\bar{K}}^0$ and $V=K^{\ast 0},{\bar{K}}^{\ast 0}$, thereby partially reducing their hadronic uncertainties. We show the change of the Standard Model predictions of the $L$-observables under different determinations of the ratio of the relevant form factors (with correlations) including lattice QCD data and a novel light-cone sum rule analysis. In addition, we provide precise results for all $B_{d,s}\to K^{(\ast )}$ form factors in machine-readable files. We find that the inclusion of our up-to-date results, as well as the use or omission of lattice QCD data for the form factors, has a significant impact on the $L$-observables. We also discuss how the New Physics interpretation is affected by the updated form factors and present revised predictions for the mechanism identified in our analysis of $B\to VP$ decays, now employing more suitable new experimental observables defined in this paper.

   hep-phhep-latJHEP(2025)·7 citations
5. 05*

   Implications of DESI for Dark Matter & Cosmic Birefringence

   Basabendu Barman🇮🇳 · Sudhakantha Girmohanta🇨🇳

   We explore an interacting dark matter (DM)-dark energy (DE) framework that naturally yields an effective dynamical DE equation of state crossing the phantom barrier at early times, as indicated by recent DESI data, while also accounting for the observed isotropic rotation of the cosmic microwave background (CMB) linear polarization. Within this unified framework, we also explain the DM relic abundance without introducing additional fields or couplings. Depending on the DE potential, we identify two viable scenarios: a superheavy freeze-in DM requiring a high reheating temperature, or a strongly interacting dark sector with a GeV-TeV scale thermal DM candidate.

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

   Dark matter spikes with strongly self-interacting particles

   Boris Betancourt Kamenetskaia🇩🇪 · Motoko Fujiwara🇩🇪 · Alejandro Ibarra🇩🇪 · Takashi Toma🇯🇵

   An unavoidable prediction of scenarios with Dark Matter (DM) self-interactions is the existence of number changing processes that convert $n$ initial DM particles into $m$ final ones ($n\to m$ processes), possibly accompanied by Standard Model particles. We argue that the $n\to m$ processes could be probed in DM spikes at the center of galaxies, where the high density may allow sizable rates. We systematically study the implications of the $n\to m$ processes in DM spikes, including other possible interactions involving DM, such as annihilation and self-scattering. We find that for $n\ge 3$, the spike is significantly depleted for $n\to m$ cross-sections favored by DM production via thermal freeze-out. On the other hand, the semi-annihilation of two DM particles into one DM particle and one Standard Model particle preserves in general the structure of the spike. Such density modifications significantly affect phenomenological studies of both astrophysics and particle DM processes around DM spikes.

   hep-phJCAP(2025)·9 citations
7. 07*

   Non-equilibrium real-time dynamics and transport coefficients in Light-Front Holographic QCD

   Fidele J. Twagirayezu🇺🇸

   We propose an extension of Light-Front Holographic QCD (LFHQCD) to investigate non-equilibrium real-time dynamics and transport properties of strongly coupled QCD matter. While LFHQCD has been successfully applied to hadronic spectroscopy and parton distributions, its potential for modeling transport phenomena remains unexplored. We develop a light-front framework to compute key transport coefficients-such as shear viscosity, bulk viscosity, and the jet quenching parameter-by introducing finite-temperature and density effects via holographic black brane backgrounds and incorporating metric fluctuations in the AdS bulk. Using the light-front Schrodinger equation with temperature-modified effective potentials, we derive analytic and numerical results for the dissipative response functions of the strongly coupled quark-gluon plasma. Our approach leverages the Minkowski-space wavefunctions of LFHQCD, enabling real-time modeling of pre-equilibrium and thermalization dynamics inaccessible to Euclidean lattice simulations. This study opens a new frontier in holographic QCD phenomenology and offers testable predictions relevant to heavy-ion collisions at RHIC and LHC.

   hep-phJ.Subatomic Part.Cosmol.(2026)·1 citation
8. 08*

   Tri-hypercharge versus tri-darkcharge

   Duong Van Loi🇻🇳 · A.E. Cárcamo Hernández🇨🇱 · Van Que Tran🇹🇼 · N. T. Duy🇻🇳

   We propose a minimal, ultraviolet-complete, and renormalizable extension of the Standard Model, in which the three generations of ordinary fermions are distinguished by family-dependent hypercharges, while three right-handed neutrinos are separated by a dark gauge symmetry that is trivial for all Standard Model fields. This setup yields a fully flipped inert doublet model. The model naturally realizes a hybrid scotoseesaw mechanism that accounts for the smallness of neutrino masses and the largeness of lepton mixing. Simultaneously, it explains the stability and relic abundance of dark matter through a residual dark parity and addresses the hierarchies of charged fermion masses and the suppression of quark mixing via higher-dimensional operators involving high-scale scalar singlets and vector-like fermions. We explore the phenomenological implications of the model and derive constraints from electroweak precision tests, collider searches, flavor-changing processes, and observations of dark matter.

   hep-phhep-thEPJC(2025)·5 citations
9. 09*

   Studying Maximal Entanglement and Bell Nonlocality at an Electron-Ion Collider

   Wei Qi🇨🇳 · Zijing Guo🇨🇳 · Bo-Wen Xiao🇨🇳

   In this paper, we propose to test quantum entanglement and Bell nonlocality at an Electron-Ion Collider (EIC). By computing the spin correlations in quark-antiquark pairs produced via photon-gluon fusion, we find that longitudinally polarized photons produce maximal entanglement at leading order, while transversely polarized photons generate significant entanglement near the threshold and in the ultra-relativistic regime. Compared to hadron colliders, the EIC provides a cleaner experimental environment for measuring entanglement through the ${\gamma }^{\ast }g\to q\bar{q}$ channel, offering a strong signal and a promising avenue to verify Bell nonlocality. This study extends entanglement measurements to the EIC, presenting new opportunities to explore the interplay of quantum information phenomena and hadronic physics in the EIC era.

   hep-phhep-exnucl-exnucl-th+1PRD(2026)·32 citations
10. 10*

    Revisiting the Realistic Intersecting D6-Brane Model with positive and negative {\mu} Terms

    Imtiaz Khan🇨🇳 · Ali Muhammad🇨🇳 · Tianjun Li🇨🇳 · Shabbar Raza🇵🇰

    In light of current constraints from supersymmetry (SUSY) searches within the LHC, as well as findings from direct dark matter detection experiments such as LUX-ZEPLIN (LZ), we revisit the three-family Pati-Salam model derived from intersecting D6-branes in Type IIA string theory compactified on the $T^6/({\mathbb{Z}}_2\times {\mathbb{Z}}_2)$ orientifold, known for its realistic low-energy phenomenology. Since the muon anomalous magnetic moment might be in accordance with the Standard Model prediction, we conduct a comprehensive scan over the model's parameter space for each sign of the Higgsino mass parameter, $\mu <0$ and $\mu >0$. We find that the gravitino mass is typically greater than 1.5 TeV in both scenarios while simultaneously satisfying the LHC SUSY bounds, B-physics observables, and the Higgs mass constraint. Within the experimentally viable region of the parameter space, the sparticle mass spectra fall within the following ranges: gluinos lie in the range 2-18 TeV; first- and second-generation squarks and sleptons span 3-16 TeV and 1-6 TeV, respectively. For third-generation sfermions, the lightest stop, which can satisfy the dark matter relic density via neutralino-stop coannihilation consistent with the \textit{Planck} 5$\sigma$ bounds, has a mass in the range 0.5-1.2 TeV. The lightest neutralino can be as heavy as 2.9 TeV. Additionally, the lightest stau can be as light as 200 GeV or as heavy as 5.2 TeV. We identify several viable mechanisms, including multiple coannihilation channels and resonance mechanisms, by which the observed dark matter relic abundance is successfully realized.

    hep-phPRD(2025)·0 citations
11. 11*

    Unitarity-Conserving Non-Minimally Coupled Inflation and the ACT Spectral Index

    J.McDonald🇬🇧

    The Atacama Cosmology Telescope (ACT) collaboration has reported a scalar spectral index $n_s=0.9743\pm 0.0034$. This is substantially larger than the classical prediction of non-minimally coupled inflation models such as Higgs Inflation, $n_s\approx 0.965$. Here we revisit the unitarity-conserving non-minimally coupled inflation model proposed in [1]. We show that when the inflaton is a complex non-minimally coupled gauge singlet scalar with additional interactions in the Jordan frame to maintain unitarity, the model predicts $n_s=0.9730$ and $r\approx 9\times 10^{-6}$ for scalar self-coupling $\lambda =0.1$.

    hep-phastro-ph.COPRD(2025)·25 citations
12. 12*

    Double Higgs Production via Vector Boson Fusion in SMEFT

    Athanasios Dedes🇬🇷 · Janusz Rosiek🇵🇱 · Michał Ryczkowski🇮🇹

    While gluon fusion dominates Higgs pair production at the LHC, vector boson fusion (VBF) offers a unique window into Beyond the Standard Model (BSM) physics through its distinctive kinematic features and direct sensitivity to Higgs-vector boson interactions. We perform a comprehensive analysis of double Higgs production via VBF in the Standard Model Effective Field Theory (SMEFT), systematically investigating how dimension-6 and dimension-8 bosonic operators - particularly those involving field derivatives - can enhance the production rate. We identify the most relevant Wilson coefficients (WCs) affecting the trilinear Higgs coupling ($hhh$) and Higgs-vector boson interactions ($hVV$, $hhVV$). Using constraints from global fits and interpolating fit results for unconstrained WCs with Naive Dimensional Analysis, we assess their effects on the $VV\to hh$ ($V=W,Z$) scattering amplitudes and cross-sections. Our analysis includes a study of EFT convergence and validity in models with scalar extensions of the SM. Numerical simulations for the planned High-Luminosity LHC experiment (HL-LHC) in general reveal only a modest and challenging to detect enhancement of the VBF di-Higgs production rate over the SM prediction. However, we show that in optimistic scenarios, such a process could be observed at the HL-LHC. In certain cases, when the enhancement is dominated by the dimension-6 or dimension-8 operators containing field derivatives (and thus leading to stronger energy-dependent effects), this channel becomes competitive with di-Higgs production via gluon fusion. This work highlights the role of VBF di-Higgs production as a complementary channel for probing anomalous Higgs couplings and their impact on BSM physics.

    hep-phPRD(2025)·6 citations
13. 13*

    Proposed measurement of longitudinally polarised vector bosons in $WH$ and $ZH$ production at Hadron colliders

    Rosa Colyer🇬🇧 · Dominik Duda🇬🇧

    The longitudinal polarisation states of the $W$ and $Z$ bosons arise during electroweak (EW) symmetry breaking as the vector bosons absorb the Higgs boson's massless degrees of freedom. Consequently, these states are intrinsically linked to the EW symmetry breaking mechanism. Measuring the Higgs boson's coupling to them thus offers a unique opportunity to deepen our understanding of EW symmetry breaking and potentially opens a window to physics beyond the Standard Model. This work studies vector boson polarisation in associated $WH$ and $ZH$ production at the LHC, proposing analysis strategies for their measurement. We explore kinematic and angular observables and employ machine learning to optimise the separation between the longitudinal and transverse polarisation states. Furthermore, we perform a statistical analysis to assess the feasibility of observing longitudinally polarised $W^{\pm }$ or $Z$ boson production in association with a Higgs boson ($W_{\mathrm{L}}^{\pm }H$ and $Z_{\mathrm{L}}H$) in the ${\ell }^{\pm }\nu \gamma \gamma$ and ${\ell }^{\pm }{\ell }^{\mp }\gamma \gamma$ final states at the LHC. Our studies forecast that $W_{\mathrm{L}}^{\pm }H$ production could be measured by the LHC experiments with $>5.0\sigma$ significance using 300 fb${}^{-1}$ of 14\,TeV proton-proton collision data. We project inclusive $W_{\mathrm{L}}^{\pm }H$ cross section measurement precisions of approximately $30\%$, $15\%$, and $10\%$ with 300 fb${}^{-1}$, 1000 fb${}^{-1}$, and 3000 fb${}^{-1}$, respectively. For $Z_{\mathrm{L}}H$ production, we forecast a measurement reaching $\sim 3.4\sigma$ significance and $35\%$ precision with 3000 fb${}^{-1}$. Based on these results, we recommend repeating these studies using LHC data.

    hep-phhep-ex3 citations
14. 14*

    Dark energy and QCD instanton vacuum in Friedmann-Lemaitre-Robertson-Walker universe

    M. M. Musakhanov🇺🇿

    The standard model of the universe, $\lambda$CDM, is based on the Friedmann-Lemaître-Robertson-Walker metric with a flat three-dimensional coordinate space and the Friedmann equations~\cite{ParticleDataGroup:2024cfk}. The cosmological constant $\lambda$ provides the cancellation of the matter field contributions in the flat (Minkowski) space, as was proposed long ago in 1967 by Zeldovich. The dynamical dark energy appears on the surface of the vacuum energy of matter fields at the flat (Minkowski) space. Within the Standard Model, the gluon Yang-Mills (YM) fields are playing a specific role since the properties of their vacuum, where there is the presence of the gluon condensate, provide the nonperturbative vacuum energy. It is natural to apply the successful instanton liquid model (ILM) of the QCD vacuum and its lowest excitations. Our aim is to calculate the contribution of gluon YM fields to the dark energy density. We find that the universe metric is generating the QCD vacuum excitation, which gives the contribution to the dark energy density. But this one may hardly play a central role in the dynamics of the universe, since its timescale is too small. We also find the equation-of-state parameters $w_0=-1,w_a=0$ in accordance with $\lambda$CDM, while the newest data, analyzed at~\cite{Shajib:2025tpd}, give them at least in the range $-0.91<w_0<-0.73,-1.05<w_a<-0.65$. They are requesting a contribution from an ultralight scalars such an axions, or from YM field topological configurations with the nontrivial holonomy due to the deviation from a pure de Sitter state ~\cite{VanWaerbeke:2025shm}.

    hep-phPRD(2025)·0 citations
15. 15*

    $\eta$-${\eta }^{\prime }$ mixing and its application in the $B^{+}/D^{+}/D_s^{+}\to {\eta }^{(\prime )}{\ell }^{+}{\nu }_{\ell }$ decays

    Yu-Jie Zhang🇨🇳 · Xing-Gang Wu🇨🇳 · Dan-Dan Hu🇨🇳 · Long Zeng🇨🇳

    In this paper, we take into account the intrinsic charm and gluonic contents into the $\eta -{\eta }^{\prime }$ mixing scheme and formulate the tetramixing $\eta -{\eta }^{\prime }-G-{\eta }_c$ to study the mixing properties of ${\eta }^{(\prime )}$ mesons. Using the newly derived mixing parameters, we calculate the transition form factors (TFFs) of $B^{+}/D^{+}/D_s^{+}\to {\eta }^{(\prime )}$ within the QCD light-cone sum rules up to next-to-leading order QCD corrections and twist-4 contributions. Using the extrapolated TFFs, we then calculate the decay widths and branching fractions of the semi-leptonic decays $B^{+}/D^{+}/D_s^{+}\to {\eta }^{(\prime )}{\ell }^{+}{\nu }_{\ell }$. Our results are consistent with the recent Belle and BES-III measurements within reasonable errors.

    hep-phPRD(2025)·5 citations
16. 16*

    QCD Axion Conversion in Magnetospheres of Neutron Stars

    Shubham Yadav🇮🇳

    The axion-converted-photons flux is a principal window for searching QCD axions as a dark matter (DM) candidate. In addition to solving the strong CP problem, these may explain the properties of the mysterious DM. Neutron star (NS) cooling by neutrino/axion emissions rate constrains the astrophysical properties of superdense matter. We attempt to analyse the impact of strong magnetic fields on the emission properties of NS by employing the FPS equation of State (EoS). We use the Tolman Oppenheimer Volkoff (TOV) equations by considering effects of strong fields and generating profiles. We assume Cooper-pair-breaking formation (PBF) and the Bremsstrahlung process occur in the core of NS. We adopt a polynomial fit function of radial profile to analyse the effects of strong magnetic field. Our entire analysis is at an axion mass of $15$ meV and central magnetic field $B_c$=$10^{17}$ G. Our work assumes the core comprises hadronic matter of the spherically symmetric magnetized NSs. We have present the results for the energy spectrum of axions and their subsequent conversion to photons. We show that the cooling rate and the luminosity of axions for NSs change significantly due to the intense magnetic field. We report that the energy spectrum of axions from the Bremsstrahlung process dominates over the PBF process at lesser axion energies, within the possible axion mass range for PSR J1356-6429 NS. Our results reveal that the impact of the magnetic field is less at lower axion energies, indicating the necessity for including a magnetic field in axion-to-photon conversion mechanisms.

    hep-ph0 citations
17. 17*

    Theoretical Summary: Moriond QCD and High-Energy Interactions 2025

    Peter Skands🇦🇺

    The theory talks at Moriond QCD and High-Energy Interactions 2025 covered the full range of scales from BSM, top, Higgs, EW, and hard QCD physics, through resummation, factorisation, and PDFs, to hadronic, heavy-ion, nonperturbative, and lattice QCD. A few talks also touched on methodologies. We here summarise main points of most of these contributions.

    hep-phhep-th0 citations
18. 18*

    Triplet Higgs assisted leptogenesis from axion oscillation after inflation

    Sasmita Mishra🇮🇳

    Leptogenesis via axion oscillation after inflation is an alternate mechanism of thermal leptogenesis. In this mechanism, the requirement of the existence of a lepton number ($L$) violating process in equilibrium to drive the lepton number requires the temperature of leptogenesis at $\sim 10^{13}$ GeV. Triplet scalars, due to their interaction with gauge bosons, make a suitable candidate to prevail in the thermal bath via gauge scattering at such high energy. Also, owing to its interaction with Standard Model (SM) leptons and the Higgs scalar, it can mediate $\Delta L=2$ process. Moreover, just one triplet is enough to serve the purpose as opposed to thermal leptogenesis, where at least one more triplet scalar/right-handed neutrino is required to generate a sizable $CP$ violation. In this work, we study a model where the SM gauge group is extended with $U(1{)}_{\mathrm{PQ}}$, with the addition of one Higgs doublet, one scalar triplet, and one complex scalar singlet. The presence of a complex scalar singlet decouples the PQ symmetry breaking from the electroweak scale. It also provides a common source of an axion-like particle and seesaw scale. The scalar triplet offers a common link between leptogenesis via axion oscillation and neutrino mass. Further, with the presence of one triplet scalar, the lepton flavor violation process is directly determined from low-energy neutrino oscillation data.

    hep-phPRD(2025)·5 citations
19. 19*

    Flavoured jet algorithms: a comparative study

    Arnd Behring🇩🇪 · Simone Caletti🇨🇭 · Francesco Giuli🇮🇹 · Radoslaw Grabarczyk🇬🇧 · Andreas Hinzmann🇩🇪 · Alexander Huss🇨🇭 · Joey Huston🇺🇸 · Ezra D. Lesser🇨🇭 · Simone Marzani🇮🇹 · Davide Napoletano🇮🇹 · Rene Poncelet🇵🇱 · Daniel Reichelt🇨🇭 and 8 other authors

    The accurate identification of heavy-flavour jets, those which originate from bottom or charm quarks, is crucial for precision studies of the Standard Model and searches for new physics. However, assigning flavour to jets presents significant challenges, primarily due to issues with infrared and collinear (IRC) safety. This paper aims to address these challenges by evaluating recently-proposed jet algorithms designed to be IRC-safe and applicable in high-precision measurements. We compare these algorithms across benchmark heavy-flavour production processes and kinematic regimes that are relevant for LHC phenomenology. Exploiting both fixed-order calculations in QCD as well as parton shower simulations, we analyse the infrared sensitivity of these new algorithms at different stages of the event evolution and compare to flavour-labelling strategies currently adopted by LHC collaborations. The results highlight that, while all algorithms lead to more robust flavour-assignments compared to current techniques, they vary in performance depending on the observable and energy regime. The study lays groundwork for robust, flavour-aware jet analyses in current and future collider experiments to maximise the physics potential of experimental data by reducing discrepancies between theoretical and experimental methods.

    hep-phhep-exJHEP(2025)·14 citations
20. 20*

    Can Effective $4-$Quark Operators Describe Signals of a Supersymmetric Diquark Model at the LHC?

    Manuel Drees🇩🇪 · Cong Zhang🇩🇪

    The Standard Model Effective Field Theory (SMEFT) is constrained by current LHC data. Supposedly extensions of the Standard Model (SM) involving heavy particles can be constrained by matching onto the SMEFT. However, the reliability of these indirect constraints compared to those derived directly from the UV model remains an open question. In this paper, we investigate whether $4-$quark operators can accurately capture the effects of an $R-$parity-violating (RPV) supersymmetric model on the production of pairs of top quarks, for parameters that satisfy all known constraints and lead to measurable effects. We assume that the sbottom is the lightest supersymmetric particle and focus on its interaction with a light quark and a top quark; the sbottom thus acts like a specific diquark. The $4-$quark operators arise by integrating out the sbottom at tree level. We analyze measurements of inclusive top pair production by the CMS and ATLAS collaborations. We find that the $4-$quark operators can accurately describe the RPV model's effects only for very heavy sbottom squarks, where the effects are well below the sensitivity of LHC experiments for all values of the RPV coupling that satisfy unitarity constraints. Therefore present or near-future bounds on this RPV model can not be derived from SMEFT analyses.

    hep-phhep-exPRD(2026)·1 citation
21. 21*

    Connecting dilaton thermal fluctuation with the Polyakov loop at finite temperature

    Bing-Kai Sheng🇨🇳 · Yong-Liang Ma🇨🇳

    Understanding the character of the deconfinement phase transition is one of the fundamental challenges in particle physics. In this work, we derive a formula for the expectation value of the Polyakov loop -- the order parameter of the deconfinement phase transition -- in pure $\mathrm{SU}({\mathrm{N}}_{\mathrm{c}})$ gauge systems at finite temperatures starting from the Coleman\textendash Weinberg-type effective potential encoding the trace anomaly of QCD. Our results are in good agreement with the Lattice QCD data and can effectively describe the large-$N_{\mathrm{c}}$ behaviors of the expectation value of the Polyakov loop. Notably, our findings predict the strongest first-order deconfinement phase transition as $N_{\mathrm{c}}\to +\infty$. Furthermore, to establish a relation between the dilaton field and the Polyakov loop, we also derive the scale transformation rule for temperature based on quantum statistical mechanics. The results of this work may shed a light on the connection between deconfinement phase transition and evolution of scale symmetry in the thermal system.

    hep-phhep-latnucl-thJHEP(2026)·2 citations
22. 22*

    Joint analysis of reactor and accelerator CE$\nu$NS data on germanium: implications for the Standard Model and nuclear physics

    M. Atzori Corona🇮🇹 · M. Cadeddu🇮🇹 · N. Cargioli🇮🇹 · G. Co'🇮🇹 · F. Dordei🇮🇹 · C. Giunti🇮🇹

    This work presents the first comprehensive joint analysis of all available Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS) data on germanium: those observed at the Spallation Neutron Source (SNS) by the COHERENT collaboration and those of the nuclear reactors revealed by the CONUS+ experiment using germanium detectors. In addition to COHERENT and CONUS+, we incorporate reactor data from TEXONO and $\nu$GeN, thereby enhancing both the statistical significance and the systematic reliability of our study. We provide state-of-the-art determinations of key nuclear physics and Standard Model parameters, including the neutron root-mean-square (rms) radius of germanium nuclei, the weak mixing angle, and the neutrino charge radius. The observed tension of about $2\sigma$ between the COHERENT germanium measurement and the Standard Model prediction motivates a detailed reassessment of the theoretical cross-section. In particular, we examine the impact of nuclear form factors and uncertainties in the nuclear radius, as well as the potential influence of a systematic shift in the neutrino flux normalisation at the SNS. Our results highlight the reliability of CE$\nu$NS as a precision tool, reinforced by the complementarity of different experimental inputs, and lay the groundwork for future advances in the field.

    hep-phhep-exnucl-thPLB(2025)·13 citations
23. 23*

    Global QCD analysis of spin PDFs in the proton with high-$x$ and lattice constraints

    C. Cocuzza🇺🇸 · N. T. Hunt-Smith🇦🇺 · W. Melnitchouk🇺🇸 · N. Sato🇺🇸 · A. W. Thomas🇦🇺

    We perform a comprehensive global QCD analysis of spin-dependent parton distribution functions (PDFs), combining all available data on inclusive and semi-inclusive deep-inelastic scattering (DIS), as well as inclusive weak boson and jet production in polarized $pp$ collisions, simultaneously extracting spin-averaged PDFs and fragmentation functions. Including recent Jefferson Lab DIS data at high $x$, together with subleading power corrections to the leading twist framework, allows us to verify the stability of the PDFs for $W^2\ge 4$ GeV${}^2$ and quantify the uncertainties on the spin structure functions more reliably. We explore the use of new lattice QCD data on gluonic pseudo Ioffe-time distributions, which, together with jet production and high-$x$ DIS data, improve the constraints on the polarized gluon PDF. The expanded kinematic reach afforded by the data into the high-$x$ region allows us to refine the bounds on higher twist contributions to the spin structure functions, and test the validity of the Bjorken sum rule.

    hep-phhep-latnucl-thPRD(2025)·22 citations
24. 24*

    Global fits and the 95 GeV diphoton excesses in the Supersymmetric Georgi-Machacek Model

    Yingnan Xu🇨🇳 · Dikai Li🇨🇳 · Roberto Vega🇺🇸 · Roberto Vega-Morales🇪🇸 · Keping Xie🇺🇸

    Recently the ATLAS and CMS experiments have reported modest excesses in the diphoton channel at around 95 GeV.~A number of recent studies have examined whether these could be due to an extended electroweak symmetry breaking (EWSB) sector, including the well known Georgi-Machacek (GM) model.~Here we examine whether the excesses can be explained by a light exotic Higgs boson in the \emph{Supersymmetric} GM (SGM) model which has the same scalar spectrum as the conventional GM model, but with a more constrained Higgs potential and the presence of custodial Higgsino fermions.~We perform a global fit of the SGM model including all relevant production and decay channels, some of which have been neglected in previous studies, which severely constrain the parameter space.~We find that the SGM model can fit the data if the LHC diphoton excesses at 95\,GeV are due to the lightest custodial singlet Higgs boson which contributes $(5-7)\%$ to EWSB, but \emph{cannot} accommodate the LEP $b\bar{b}$ excess, in contrast to other recent studies of the GM model.~Since the SGM model has a highly constrained Higgs potential, the rest of the mass spectrum is sharply predicted, allowing for targeted searches at the LHC or future colliders.~We also compare the SGM model with the non-supersymmetric GM model and identify how they can be distinguished at the LHC or future colliders.

    hep-ph0 citations
25. 25*

    CALICO: Computing Annihilators from Linear Identities Constraining (differential) Operators

    Giuseppe Bertolini🇮🇹 · Gaia Fontana🇨🇭 · Tiziano Peraro🇮🇹

    We elaborate on the method of parametric annihilators for deriving integral relations. Parametric annihilators are differential operators that annihilate multivalued integration kernels appearing in suitable integral representations of special functions. We illustrate this approach in a way that applies to a broad variety of integral representations. We describe a method for computing parametric annihilators based on efficient linear solvers and use them to derive relations between a wide class of special functions related to important problems in high-energy physics. We also formulate a similar method for deriving differential equations satisfied by the independent integrals within an integral family. We show applications to several classes of special functions, including hypergeometric functions, loop integrals in various representations (including Baikov, loop-by-loop Baikov, Lee-Pomeransky and Schwinger representations) and duals of loop integrals. We finally present the public Mathematica package CALICO for computing parametric annihilators and its usage in several examples of high relevance in theoretical particle physics.

    hep-phhep-thJHEP(2025)·7 citations
26. 26*

    Two Higgs Doublet Solutions to the Strong CP Problem

    Quentin Bonnefoy🇫🇷 · Lawrence J. Hall🇺🇸 · Claudio Andrea Manzari🇺🇸 · Bea Noether🇺🇸

    We solve the strong CP problem in a broad class of two Higgs doublet theories that will be probed at the Large Hadron Collider and at future colliders. These theories feature CP and Abelian flavor symmetries, both broken softly in the scalar potential, that yield realistic quark masses and mixings. The flavor symmetry charges are chosen so that $\bar{\theta }=0$ at tree level for all values of the Yukawa and quartic couplings of the theory. We prove that in all such theories the 1-loop contribution to $\bar{\theta }$ also vanishes, independently of the mass scale of the second Higgs doublet. We study two illustrative models with flavor group ${\mathbb{Z}}_3$. The direct contributions to the neutron electric dipole moment are negligible in both models. While the 2-loop contribution to $\bar{\theta }$ is less than $10^{-12}$ in one model, it can be as large as $10^{-10}$ in the other, yielding the prospect of a signal in planned experiments. Even with Abelian flavor symmetries, CP violation in neutral kaon mixing is generally expected to yield naturalness bounds on the masses of additional Higgs doublets of order 20 TeV. We prove that for all models in our class, where the flavor symmetry forces $\bar{\theta }$ to vanish at tree-level, the flavor-changing neutral currents are CP-conserving, yielding model-dependent bounds from neutral meson mixing near 1 TeV. Mixing of the two CP-even scalars gives corrections to the couplings of the 125 GeV Higgs state to $\bar{t}t,\bar{b}b,\bar{c}c,\bar{\tau }\tau$ and $\bar{\mu }\mu$, giving possible signals at high luminosity runs at LHC and at future colliders. Furthermore, distinctive correlations between corrections in the various channels can probe the underlying flavor symmetry.

    hep-phhep-exhep-thJHEP(2026)·4 citations
27. 27*

    Multi-messenger FIMP

    Debasish Borah🇮🇳 · Nayan Das🇮🇳 · Sahabub Jahedi🇨🇳 · Dipankar Pradhan🇮🇳

    We propose a multi-messenger frontier probe of non-thermal or freeze-in massive particle (FIMP) dark matter (DM) by considering an effective field theory (EFT) setup. Assuming leptophilic operators connecting DM with the standard model (SM) bath, we consider DM mass ($m_{\mathrm{DM}}$) and the reheat temperature of the Universe ($T_{\mathrm{rh}}$) in a regime which prevents DM-SM thermalisation. Low $T_{\mathrm{rh}}$ allows sizeable DM-SM interactions even for non-thermal DM allowing the latter to be probed at direct, indirect detection frontiers as well as future electron-positron and muon colliders. An extended reheating period governed by monomial inflaton potential after its slow-roll phase not only generates the required abundance of non-thermal DM via ultraviolet (UV) freeze-in but also brings the scale-invariant primordial gravitational waves (GW) within reach of near future experiments across a wide range of frequencies. While particle physics experiments can probe $T_{\mathrm{rh}}\sim O(10)$ GeV and FIMP DM with mass $m_{\mathrm{DM}}\sim O(1)$ TeV, future GW detectors are sensitive to a much wider parameter space.

    hep-phastro-ph.COJHEP(2025)·10 citations
28. 28*

    The fast, the slow and the merging: probes of evaporating memory burdened PBHs

    Alessandro Dondarini🇮🇹 · Giulio Marino🇮🇹 · Paolo Panci🇮🇹 · Michael Zantedeschi🇮🇹

    The so-called memory-burden effect implies that evaporating Primordial Black Holes (PBHs) inevitably stabilize before complete decay. This stabilization opens a new mass window for PBH Dark Matter below $10^{15}$g. The transition to the memory-burdened phase is not instantaneous but unfolds over cosmological timescales, with some PBHs entering this phase in the present epoch. Additionally, a fraction of PBHs undergo mergers today, forming ''young'' semiclassical black holes that evaporate at unsuppressed rates. Both processes generate fluxes of stable astrophysical particles, which are constrained by current measurements of high-energy $\gamma$-rays and neutrinos. Moreover, the steep increase in energy injection at higher redshifts perturbs the ionization history of the Universe, leading to complementary bounds from observations of the CMB temperature and polarization anisotropies. We find that the reopened window enabled by the memory-burden effect is largely within reach of detection, both locally and across cosmological distances. We further describe how our findings restrict the values of the critical exponent characterizing the memory burden phenomenon.

    hep-phastro-ph.COastro-ph.HEgr-qc+1JCAP(2025)·35 citations
29. 29*

    Dark Matter Freeze-In and Small-Scale Observables: Novel Mass Bounds and Viable Particle Candidates

    Francesco D'Eramo🇮🇹 · Alessandro Lenoci🇮🇱 · Ariane Dekker🇺🇸

    The suppression of cosmological structure at small scales is a key signature of dark matter (DM) produced via freeze-in in the low-mass regime. We present a comprehensive analysis of its impact, incorporating recent constraints from Milky Way satellite counts, strong gravitational lensing with JWST data, and the Lyman-$\alpha$ forest. We adopt a general strategy to translate existing warm dark matter (WDM) bounds into lower mass limits for a broad class of DM candidates characterized by quasi-thermal phase space distributions. The benefits of this approach include computational efficiency and the ability to explore a wide range of models. We derive model-independent bounds for DM produced via two-body decays, scatterings, and three-body decays, and apply the framework to concrete scenarios such as the Higgs portal, sterile neutrinos, axion-like particles, and the dark photon portal. Results from specific models confirm the validity of the model-independent analysis.

    hep-phastro-ph.COPRD(2025)·19 citations
30. 30*

    A Determination of ${\alpha }_s(m_Z)$ at $\mathbf{a}{\mathbf{N}}^3\mathbf{L}{\mathbf{O}}_{\mathbf{QCD}}\otimes {\mathbf{NLO}}_{\mathbf{QED}}$ Accuracy from a Global PDF Analysis

    The NNPDF Collaboration: Richard D. Ball🇬🇧 · Andrea Barontini🇮🇹 · Juan Cruz-Martinez🇨🇭 · Stefano Forte🇮🇹 · Felix Hekhorn🇫🇮 · Emanuele R. Nocera🇮🇹 · Juan Rojo🇳🇱 · Roy Stegeman🇬🇧

    We present a determination of the strong coupling ${\alpha }_s(m_Z)$ from a global dataset including both fixed-target and collider data from deep-inelastic scattering and a variety of hadronic processes, with a simultaneous determination of parton distribution functions (PDFs) based on the NNPDF4.0 methodology. This determination is performed at NNLO and approximate N${}^3$LO (aN${}^3$LO) perturbative QCD accuracy, including QED corrections and a photon PDF up to NLO accuracy. We extract ${\alpha }_s$ using two independent methodologies, both of which take into account the cross-correlation between ${\alpha }_s$ and the PDFs. The two methodologies are validated by closure tests that allow us to detect and remove or correct for several sources of bias, and lead to mutually consistent results. We account for all correlated experimental uncertainties, as well as correlated theoretical uncertainties related to missing higher order perturbative corrections (MHOUs). We study the perturbative convergence of our results and the impact of QED corrections. We assess individual sources of uncertainty, specifically MHOUs and the value of the top quark mass. We provide a detailed appraisal of methodological choices, including the choice of input dataset, the form of solution of evolution equation, the treatment of the experimental covariance matrix, and the details of Monte Carlo data generation. We find ${\alpha }_s(m_Z)=0.1194_{-0.0014}^{+0.0007}$ at aN${}^3$LO${}_{\mathrm{QCD}}\otimes {\mathrm{NLO}}_{\mathrm{QED}}$ accuracy, consistent with the latest PDG average and with recent lattice results.

    hep-phhep-exEPJC(2025)·20 citations
31. 31*

    Theory Uncertainties in the Extraction of ${\alpha }_s$ from Drell-Yan at Small Transverse Momentum

    Thomas Cridge🇧🇪 · Giulia Marinelli🇩🇪 · Frank J. Tackmann🇩🇪

    We perform a detailed pseudodata study to estimate the expected theory uncertainty in the extraction of the strong coupling constant, ${\alpha }_s(m_Z)$, from a fit to the measured Drell-Yan transverse momentum ($q_T$) spectrum at small $q_T\ll m_Z$. We consider two approaches to estimate the dominant perturbative uncertainties. We first discuss that the traditional approach based on varying unphysical scales is insufficient here because it cannot correctly account for bin-by-bin theory correlations in the $q_T$ spectrum, which are critically important in this case. We then use this case as a nontrivial application of a new approach based on theory nuisance parameters (TNPs), which encodes the correct theory correlations by construction. Moreover, the TNPs can be profiled in the fit thereby allowing the data to constrain the theory uncertainties in a consistent manner. We furthermore discuss the interplay with nonperturbative effects in the peak region $q_T\lesssim 10$ GeV, from where most of the ${\alpha }_s$ sensitivity originates. The associated nonperturbative uncertainties on ${\alpha }_s$ when fitting only the $q_T$ spectrum are large. They can in principle be reduced by including additional constraints on the nonperturbative Collins-Soper kernel from lattice QCD calculations. We find that these improvements in the treatment of perturbative and nonperturbative uncertainties and their correlations will enable a competitive ${\alpha }_s$ extraction from Drell-Yan data at small $q_T$. We also discuss the implications of our findings, calling into question a recent ${\alpha }_s$ extraction from the $Z$ $q_T$ spectrum by the ATLAS experiment.

    hep-phhep-exJHEP(2025)·10 citations
32. 32*

    Cosmographic analysis of sign-switching dark energy

    Mariam Bouhmadi-López🇪🇸 · Beñat Ibarra-Uriondo🇪🇸

    Inspired by the well-studied ${\Lambda }_{\mathrm{s}}$CDM model, we propose and investigate a class of dynamical dark energy models that evolve from a negative cosmological constant, transitioning to a positive value at low redshifts. Specifically, we introduce a dark energy framework based on a generalised ladder-step function for the cosmological constant. Furthermore, we present two additional models in which the cosmological constant undergoes a smooth sign change at a specified redshift. We provide a detailed discussion of the construction and theoretical properties of these models, analysing their background cosmological evolution using a cosmographic approach and the statefinder hierarchy parameters. Our results are compared with those obtained for the standard $\Lambda$CDM and ${\Lambda }_{\mathrm{s}}$CDM models. We also perform a careful analysis of the types of singularities that may arise in these models due to a sign change in the cosmological constant. Notably, we show that a continuous sign change removes the sudden singularity present in the ${\Lambda }_{\mathrm{s}}$CDM model, replacing it with a milder $w$-singularity.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2025)·30 citations
33. 33*

    Compton amplitude and Contact term(s) in the Spinor Helicity formalism

    Aakash Kumar · Arnab Rudra · Rahul Shaw

    In gauge theories, contact terms play an important role in ensuring gauge invariance. In the spinor helicity formalism, the choice of a gauge-fixing condition manifests itself in the form of the choice of reference vector to write the massless polarization vector(s). However, this choice must be irrelevant in any gauge-invariant observable. We use this principle to determine contact term for Electromagnetic Compton amplitude. We considered three-point function between two massive particles \& a photon to be one which is responsible for soft photon theorem/Coulomb and demonstrate that it is possible to use the above-mentioned principle to find the contact term for the tree-level Compton amplitude of two bosonic massive spinning particles and two photons. The final result does not suffer from any spurious poles.

    ↳ hep-thhep-ph1 citation
34. 34*

    Inflationary attractors and radiative corrections in light of ACT data

    William J. Wolf🇬🇧

    In light of the recent results from the Atacama Cosmology Telescope (ACT), which have provided a notable shift in the constraints on $(n_s,r)$ and placed several otherwise viable models of inflation in tension with the latest data, we investigate the possible effects that radiative corrections can have on $\xi$-attractor and $\alpha$-attractor models of inflation. These models, which share much in common with Starobinsky inflation, have likewise been put under pressure by these results. We find that percent (and even sub-percent) level radiative corrections can easily shift both of these classes of inflation models comfortably into the regions of parameter space favoured by the most recent constraints. However, the flexibility under such corrections calls into question to what extent it is possible to precisely pin down model-specific predictions for important cosmological observables.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2026)·69 citations
35. 35*

    From Explicit Diffeomorphism Breaking to Spontaneous Unimodularization

    Yuri Bonder🇲🇽 · Johas D. Morales🇲🇽

    This contribution investigates modifications of General Relativity that allow or mimic energy nonconservation. We focus on Unimodular Gravity (UG), a theory that explicitly breaks diffeomorphism invariance, and show that it can lead to particle acceleration, opening the door to experimental constraints. We also argue that UG admits a well-posed initial value formulation, despite the presence of nondynamical structures. Finally, we introduce a simple model that spontaneously mimics UG, but in which a cosmological constant cannot arise as an integration constant.

    ↳ gr-qchep-ph1 citation
36. 36*

    On the Renormalization Group flow of distributions

    Astrid Eichhorn🇩🇪 · Aaron Held🇫🇷

    Renormalization Group flows relate the values of couplings at different scales. Here, we go beyond the Renormalization Group flow of individual trajectories and derive an evolution equation for a distribution on the space of couplings. This shift in perspective can provide new insights, even in theories for which the Renormalization Group flow of individual couplings is well understood. As a first application, we propagate errors under the Renormalization Group flow. Characteristic properties of an error distribution, such as its maximum or highest density region, cannot be propagated at the level of individual couplings, but require our evolution equation for the distribution on the space of couplings. We demonstrate this by calculating the most probable value for the metastability scale in the Higgs sector of the Standard Model. Our second application is the emergence of structure in sets of couplings. We discover that infrared-attractive fixed points do not necessarily attract the maximum of the distribution when the Renormalization Group is evolved over a finite range of scales. Instead, sharply peaked maxima can build up at coupling values that cannot be inferred from individual trajectories. We demonstrate this emergence of structure for the Standard Model, starting from a broad distribution at the Planck scale. The Renormalization Group flow favors the phenomenological ordering of third-generation Yukawa couplings and, strikingly, we find that the most probable values for the Abelian hypercharge and Higgs quartic coupling lie close to their observed values.

    ↳ hep-thhep-ph2 citations
37. 37*

    Regular Spacetimes in the Effective Metric Description

    Mattia Damia Paciarini🇩🇰 · Mikołaj Myszkowski🇩🇰 · Francesco Sannino🇩🇰 · Vania Vellucci🇩🇰

    Over the past few decades, significant effort has been directed towards developing various regularized models for compact objects. Recently, a new observable-based parametrization was introduced to account for black hole deformations in a model-independent fashion, referred to as the Effective Metric Description (EMD) \cite{Binetti:2022xdi, DelPiano:2023fiw, DelPiano:2024gvw, DelPiano:2024nrl}. In this paper, we carry out a systematic investigation of the regularity of static and spherically symmetric spacetimes by extending the EMD. We derive the conditions under which curvature scalars remain finite everywhere and the associated spacetime is geodesically complete. Our results are then used to classify the cores of regular spacetimes based on their asymptotic behavior near the origin. To illustrate our findings, we apply our regularity conditions to known black hole examples.

    ↳ gr-qchep-phhep-thEPJC(2026)·2 citations
38. 38*

    A Complete Derivation of the Fermion Spectrum from the Recognition Composition Law

    Jonathan Washburn🇺🇸 · Elshad Allahyarov🇺🇸

    We present a first-principles derivation of the masses of all twelve known fermions -- three charged leptons, six quarks, and three neutrinos -- and the fine-structure constant ${\alpha }^{-1}$, from a single discrete functional equation, the Recognition Composition Law (RCL), with \textbf{zero continuously adjustable parameters}. The mass spectrum follows from the RCL supplemented by four regularity conditions and eight structural theorems (T1--T8): the golden ratio $\phi =(1+\sqrt{5})/2$ emerges as the unique hierarchy base (T6); an 8-step period is fixed by the 3-cube Hamiltonian cycle (T7); three spatial dimensions are selected by a unique combinatorial identity (T8). All integers entering the mass formula are the six combinatorial invariants of the 3-cube $Q_3$; none is fitted. The sole empirical input is the electron mass, which fixes an irreducible unit-conversion constant~${\tau }_0$. Predictions are confronted with PDG measurements. Charged-lepton masses are reproduced at sub-ppm accuracy for the muon and $\sim 10^{-4}$ for the tau (Table~\ref{tab:lepton_validation}). All six quark masses are predicted at integer level; first-generation quarks agree to better than $1\%$, while second/third-generation residuals of $2$--$16\%$ are expected integer-precision effects (Table~\ref{tab:quark_validation}). Neutrino mass-squared splittings agree with NuFIT~5.3 within $1$--$2\sigma$, normal ordering is predicted, and $\Sigma m_{\nu }\approx 0.063$~eV satisfies cosmological bounds. All structural claims are machine-verified in Lean~4 (179 files, 0~\texttt{sorry}; \texttt{github.com/\allowbreak jonwashburn/\allowbreak recognition-science}).

    ↳ physics.gen-phhep-ph1 citation
39. 39*

    Flavor Symmetries and Winding Modes

    Xueqi Li🇺🇸 · Xiang-Gan Liu🇺🇸 · Hans Peter Nilles🇩🇪 · Michael Ratz🇺🇸 · Alex Stewart🇺🇸

    Modular flavor symmetries have been proposed as a new way to address the flavor problem. It is known that they can emerge from string compactifications. We discuss this connection in detail, and show how the congruence subgroups of SL(2,Z), which underlie many modular flavor symmetries, emerge from stringy duality symmetries by orbifolding. This requires an analysis of massive states, which reveals a picture that is more intricate than the well-known situation on the torus. It involves towers of states of different quantum numbers, related by modular transformations. Members of different towers become massless at different points in moduli space. We also show that, at least in the Z_3 orbifold, the string selection rules can be understood as discrete remnants of continuous gauge symmetries. Non-Abelian discrete flavor symmetries arise as relics of various, relatively misaligned, continuous Abelian gauge symmetries. The generators of these U(1) symmetries give rise to CP-violating Clebsch-Gordan coefficients. If the modulus settles close to a critical point, the corresponding gauge bosons may be light enough to be searched for at future colliders.

    ↳ hep-thhep-phJHEP(2025)·4 citations
40. 40*

    Simple quintessence models in light of DESI-BAO observations

    James M. Cline🇨🇦 · Varun Muralidharan🇨🇦

    Recent analyses from the DESI collaboration suggest that the dark energy density of the Universe may be decreasing with time, slowing the acceleration of the scale factor $a$. Typically these studies are performed assuming an ansatz for the equation of state $w(a)$. In this work, we instead consider simple models of a scalar quintessence potential with linear and quadratic behavior, which could be more representative of real models than particular parametrizations of $w(a)$. We observe a significant preference for dynamical dark energy when using supernova data from DESY5 along with DESI BAO and Planck data, at the cost of slightly exacerbating the Hubble tension. However, when using supernova data from Pantheon+ or Union3, we find only a mild preference for dynamical dark energy.

    ↳ astro-ph.COhep-phPRD(2025)·33 citations
41. 41*

    Evolution of energy density fluctuations in the presence of a magnetic field

    Shreyansh S. Dave🇮🇳 · Subrata Pal🇮🇳

    In this proceeding, we study the evolution of energy density fluctuations in the presence of a static and uniform magnetic field. By numerically solving the relativistic Boltzmann-Vlasov equation within the relaxation time approximation and performing the momentum mode analysis of different wavelength fluctuations, we show that the magnetic field increases the damping of mode oscillations. This causes a qualitative change in the fluctuations present in the system at the timescale required to achieve a local equilibrium state.

    ↳ nucl-thhep-phhep-thJ.Subatomic Part.Cosmol.(2025)·0 citations
42. 42*

    Thermodynamics of black and white holes in ensemble of Planckons

    G.E. Volovik🇷🇺

    The Tsallis-Cirto non-extensive statistics with $\delta =2$ describes the processes of splitting and merging of black holes and their thermodynamics. Here we consider a toy model, which matches this generalized statistics and extends it by providing the integer valued entropy of the black hole, $S_{\mathrm{BH}}(N)=N(N-1)/2$. In this model the black hole consists of $N$ the so-called Planckons -- objects with reduced Planck mass $m_{\mathrm{P}}=1/\sqrt{8\pi G}$ -- so that its mass is quantized, $M=N{m}_{\mathrm{P}}$. The entropy of each Planckon is zero, but the entropy of black hole with $N$ Planckons is provided by the $N(N-1)/2$ degrees of freedom -- the correlations between the gravitationally attracted Planckons. This toy model can be extended to a charged Reissner-Nordström (RN) black hole, which consists of charged Planckons. Despite the charge, the statistical ensemble of Planckons remains the same, and the RN black hole with $N$ Planckons has the same entropy as the electrically neutral hole, $S_{\mathrm{RNBH}}(N)=N(N-1)/2$. This is supported by the adiabatic process of transformation from the RN to Schwarzschild black hole by varying the fine structure constant. The adiabaticity is violated in the extreme limit, when the gravitational interaction between two Planckons is compensated by the repulsion between their electric charges, and the RN black hole loses stability. The entropy of a white hole formed by the same $N$ Planckons has negative entropy, $S_{\mathrm{WH}}(N)=-N(N-1)/2$.

    ↳ gr-qchep-phJ.Exp.Theor.Phys.(2025)·7 citations
43. 43*

    Stochastic background of gravitational waves from cosmic-rays

    Aurélien Barrau🇫🇷 · Juan García-Bellido🇪🇸 · Killian Martineau🇫🇷 · Daryna Yushchenko🇫🇷

    Cosmic-rays are charged particles moving in magnetic fields. They not only emit well-known synchrotron photons but also gravitational radiation. We clarify the characteristics of the gravitational wave signal in this specific situation and underline some unexpected features. A phenomenological approximation for the radiated power is given. We derive the shape and peaking frequency of the associated stochastic backgrounds of gravitational waves for both electrons and protons, either of galactic or extra-galactic origin.

    ↳ gr-qcastro-ph.COastro-ph.GAhep-phMod.Phys.Lett.A(2026)·0 citations
44. 44*

    Self-organized criticality in a relativistic Yukawa theory with Luttinger fermions

    Holger Gies🇩🇪 · Marta Picciau🇩🇪

    We propose and investigate a Yukawa model featuring a dynamical scalar field coupled to relativistic Luttinger fermions. Using the functional renormalization group (RG) as well as large-$N_{\text{f}}$ or perturbative expansions, we observe the emergence of an infrared attractive partial fixed point in all interactions at which all couplings become RG irrelevant. At the partial fixed point, the scalar mass parameter is RG marginal, featuring a slow logarithmic running towards the regime of spontaneous symmetry breaking. The long-range behavior of the model is characterized by mass gap formation in the scalar and the fermionic sector independently of the initial conditions. Most importantly, a large scale separation between the low-energy scales and the microscopic scales, e.g., a high-energy cutoff scale, is naturally obtained for generic initial conditions without the need for any fine-tuning. We interpret the properties of our model as a relativistic version of self-organized criticality, a phenomenon observed in specific statistical or dynamical systems. This entails natural scale separation and universal long-range observables. We determine nonperturbative estimates for the latter including the scalar and fermionic mass gaps.

    ↳ hep-thhep-phInt.J.Theor.Phys.(2025)·6 citations
45. 45*

    Extensive and Intensive Aspects of Astrophysical Systems and Fine-Tuning

    Meir Shimon🇮🇱

    Most astrophysical systems in our Universe are characterized by shallow gravitational potentials, with dimensionless compactness $|\Phi |\equiv r_s/R\ll 1$, where $r_s$ and $R$ are their Schwarzschild radius and typical size, respectively. While the existence and characteristic scales of such virialized systems depend on gravity, we demonstrate that the value of $|\Phi |$ -- and thus the non-relativistic nature of most astrophysical objects -- arises from microphysical parameters, specifically the fine structure constant and the electron-to-proton mass ratio, and is fundamentally independent of the gravitational constant $G$. It then follows that peak rms values of large-scale astrophysical velocities and escape velocities associated with naturally formed astrophysical systems are determined by electromagnetic and atomic physics, not by gravitation, and that the compactness $|\Phi |$ is always set by microphysical scales -- even for the most compact objects, such as neutron stars, where $|\Phi |$ is determined by quantities like the pion-to-proton mass ratio. Our results emphasize the central but underappreciated role played by dimensionless microphysical constants in shaping the macroscopic gravitational landscape of the Universe. In particular, we clarify that this independence of the compactness $|\Phi |$ from $G$ applies specifically to entire, virialized or degeneracy pressure-supported systems, naturally formed astrophysical systems -- such as stars, galaxies, and planets -- that have reached equilibrium between self-gravity and microphysical processes. Finally, we point out that a clear distinction between intensive and extensive astrophysical/cosmological properties could potentially shed a new light on the mass hierarchy and the cosmological constant problems; both may be related to the large complexity of our Universe. (abbridged)

    ↳ gr-qcastro-ph.COhep-phUniverse(2025)·1 citation
46. 46*

    Experimental search for electric dipole moments of light radioactive nuclei

    Chavdar Dutsov🇨🇭 · Timothy Hume🇨🇭 · Maxim Pospelov🇺🇸 · Philipp Schmidt-Wellenburg🇨🇭

    We discuss a search for the electric dipole moment (EDM) of a light beta-radioactive ion using a compact ion trap by adapting the "frozen-spin" method. The measurement will be done on ions stripped of their valence electrons, thereby bypassing the significant Schiff screening that hinders the application of successful contemporary EDM searches using heavy neutral atoms and molecules to light nuclei. We identified ${}^8$Li as the most promising candidate for a proof-of-concept EDM search and we estimate that the current indirect proton EDM limit of a few $10^{-25}e\cdot$cm set by ${}^{199}$Hg measurements can be surpassed with a week of measurement time at existing facilities.

    ↳ hep-exhep-phPRD(2025)·4 citations
47. 47*

    Vacuum Geometry of the Standard Model

    Yang-Hui He🇬🇧 · Vishnu Jejjala🇿🇦 · Brent D. Nelson🇺🇸 · Hal Schenck🇺🇸 · Michael Stillman🇺🇸

    Vacuum structure of a quantum field theory is a crucial property. In theories with extended symmetries, such as supersymmetric gauge theories, the vacuum is typically a continuous manifold, called the vacuum moduli space, parametrized by the expectation values of scalar fields. Starting from the R-parity preserving superpotential at renormalizable order, we use Gröbner bases to determine the explicit structure, as an algebraic variety, of the vacuum geometry of the minimal supersymmetric extension of the Standard Model. Gröbner bases have doubly exponential computational complexity (for this case, $7^{2^{1023}}$ operations); we exploit symmetry and multigrading to render the computation tractable. This geometry has three irreducible components of complex dimensions $1$, $15$, and $29$, each being a so-called rational variety. The defining equations of the components express the solutions to F-terms and D-terms in terms of the gauge invariant operators and are interpreted in terms of classical geometric constructions.

    ↳ hep-thhep-phmath.AGPLB(2026)·0 citations
48. 48*

    Not-quite-primordial black holes

    Wenzer Qin🇺🇸 · Soubhik Kumar🇺🇸 · Priyamvada Natarajan🇺🇸 · Neal Weiner🇺🇸

    We propose a new mechanism for the formation of seeds of supermassive black holes at early cosmic epochs. Our scenario explores density fluctuations that are enhanced relative to $\Lambda$CDM expectations, but with amplitudes that are not large enough to form primordial black holes, and that can still lead to collapsed dark matter halos at very early times. For halos forming prior to $1+z\approx 200$, the Cosmic Microwave Background (CMB) is energetic enough to suppress the formation of molecular hydrogen, hence preventing cooling and fragmentation, as a consequence of which baryons falling into the potential well of the halo may undergo ``direct collapse" into a black hole. We show using a few illustrative models how this mechanism may account for the abundance of high-redshift black holes inferred from observations by the \textit{James Webb Space Telescope} while remaining consistent with limits from CMB spectral distortions. Limits on the primordial power spectrum are also derived by requiring that the universe not re-ionize too early.

    ↳ astro-ph.COastro-ph.GAhep-ph25 citations
49. 49*

    The Vacuum Moduli Space of the Minimal Supersymmetric Standard Model

    Yang-Hui He🇬🇧 · Vishnu Jejjala🇿🇦 · Brent D. Nelson🇺🇸 · Hal Schenck🇺🇸 · Michael Stillman🇬🇧

    A starting point in the study of the minimal supersymmetric Standard Model (MSSM) is the vacuum moduli space, which is a highly complicated algebraic variety: it is the image of an affine variety $X\subset {\mathbb{C}}^{49}$ under a symplectic quotient map $\varphi$ to ${\mathbb{C}}^{973}$. Previous work computed the vacuum moduli space of the electroweak sector; geometrically this corresponds to studying a restriction of $\varphi$: ${\mathbb{C}}^{13}\stackrel{{\varphi }^{\text{res}}}{⟶}{\mathbb{C}}^{22}$. We analyze the geometry of the full vacuum moduli space for superpotentials $W_{\mathrm{minimal}}$ (without neutrinos) and $W_{\mathrm{MSSM}}$ (with neutrinos) in ${\mathbb{C}}^{973}$. In both cases, we prove that $X$ consists of three irreducible components $X_1$, $X_2$, and $X_3$, and determine the images $M_i$ of the $X_i$ under $\varphi$. For $W_{\mathrm{minimal}}$ we show they have, respectively, dimensions $1$, $15$, and $29$, and prove that each of the $M_i$ is a rational variety, while for $W_{\mathrm{MSSM}}$ we show that $M_3$ is the only component. Restricting the $M_i$ to the electroweak sector, we recover known results. We describe the components of the vacuum moduli space geometrically in terms of incidence varieties to a product of Segre varieties.

    ↳ hep-thhep-phmath.AGPRD(2026)·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.