Thu·Sep 4, 2025Thursday·September 4, 2025

1. 01*

   Burdening (or not) gravitational waves in the presence of primordial black holes

   Mathieu Gross🇫🇷 · Md Riajul Haque🇮🇳 · Yann Mambrini🇫🇷

   We present the spectrum of primordial gravitational wave (GW) expected from the presence of primordial black holes (PBH) and inflaton in the early Universe. For the first time, we combine the waves produced by the PBH decay, with their density fluctuation counterpart, as well as their effects on the GW produced by the inflaton {\it after} (high frequency modes) and {\it before} (low frequency modes) the end of inflation. We generalize our study for a potential $V(\varphi )\propto {\varphi }^k$ during reheating. We also extend our study, taking into account a possible memory burden effect to see how it can affect the shape of the spectrum.

   hep-phastro-ph.COgr-qcPRD(2025)·11 citations
2. 02*

   Analysis-ready Generative Unfolding

   Anja Butter🇩🇪 · Nathan Huetsch🇩🇪 · Vinicius Mikuni🇺🇸 · Benjamin Nachman🇺🇸 · Sofia Palacios Schweitzer🇩🇪

   Machine Learning (ML)-based unfolding methods have enabled high-dimensional and unbinned differential cross section measurements. While a suite of such methods has been proposed, most focus exclusively on the challenge of statistically removing resolution effects. In practice, unfolding methods must also account for impurities and finite acceptance and efficiency effects. In this paper, we extend a class of unfolding methods based on generative ML to include the full suite of effects relevant for cross section measurements. Our new methods include fully generative solutions as well as generative-discriminative hybrid approaches (GenFoldG and GenFoldC). We demonstrate these new techniques in both Gaussian and simulated LHC examples. Overall, we find that both methods are able to accommodate all effects, thus adding a complementary and analysis-ready method to the unfolding toolkit.

   hep-phhep-ex8 citations
3. 03*

   Constraining axial non-standard neutrino interactions with MINOS and MINOS+

   S. Abbaslu🇮🇷 · Y. Farzan🇮🇷

   We show that the neutral current data of the MINOS and MINOS+ experiments can provide information on the axial neutral current non-standard interactions of neutrinos with the $u$ and $d$ quarks; {\it i.e.,} on ${ϵ}_{\alpha \beta }^{Aq}$. We derive bounds on the $ee$, $e\tau$ and $\tau \tau$ components of these couplings and show that the MINOS(+) bounds on ${ϵ}_{e\tau }^{Aq}$ and ${ϵ}_{\tau \tau }^{Aq}$ are currently the world leading ones. The bound on the isospin singlet case, ${ϵ}_{\tau \tau }^{Au}={ϵ}_{\tau \tau }^{Ad}$ is of particular interest because while this isospin singlet NSI is theoretically motivated, it was practically unconstrained before these results.

   hep-phEPJC(2026)·3 citations
4. 04*

   Exploring Fermionic Dark Matter in the Presence of Scalar Leptoquarks

   Shyamashish Dey🇮🇳 · Santosh Kumar Rai🇮🇳

   We study an extension of the vector-like lepton dark matter model by introducing scalar leptoquarks that modify the properties of the vector-like lepton dark matter candidate, helping it evade stringent direct detection constraints. In the minimal setup, the neutral component of a pure $SU(2)$ doublet vector-like lepton fails to simultaneously account for the observed relic abundance while remaining consistent with current direct detection limits. We show that the addition of the scalar leptoquarks can induce corrections to the mass of the vector-like lepton dark matter, splitting it into two non-degenerate pseudo-Dirac states. This mass splitting can help evade the direct detection bounds naturally. In addition, the extended setup also opens up a larger parameter space of the model that can accommodate the correct relic density.

   hep-phEPJC(2026)·1 citation
5. 05*

   Correlator with tensor currents and two masses at two loops

   Terry Generet🇬🇧 · Nico Gubernari🇬🇧 · Eetu Loisa🇬🇧

   We calculate the vacuum-to-vacuum correlator of two quark tensor currents with two massive quarks, retaining full momentum dependence. For the first time, we include perturbative corrections up to next-to-leading order. Our fully analytical expressions are provided in machine-readable form. Furthermore, we present numerical results for various input parameters, including an estimate of the scale uncertainties. Our results are essential input for applications of dispersive methods, including unitarity bounds and QCD sum rules.

   hep-phEPJC(2026)·3 citations
6. 06*

   Perturbative QCD

   Gudrun Heinrich🇩🇪 · Anton Olsson🇩🇪

   We give an introduction to perturbative Quantum Chromodynamics, focusing on a pedagogical description of concepts and methods to calculate cross sections measured at high energy colliders. After introducing basic concepts that allow for a perturbative expansion, such as factorisation and asymptotic freedom, we introduce loop integrals and the treatment of ultraviolet and infrared divergences in QCD. The definition of jets and event shape observables is also discussed. Finally, we give a brief overview of the current state of the art.

   hep-ph1 citation
7. 07*

   Precision gravity constraints on large dark sectors

   Christopher Ewasiuk🇺🇸 · Stefano Profumo🇺🇸

   General relativity, treated as a low energy effective field theory, predicts quantum corrections to Newtons law of gravitation arising from loops of matter and graviton fields. While these corrections are negligible for the Standard Model particle content, the situation changes dramatically in the presence of a hidden or dark sector containing a very large number of light degrees of freedom. In such cases, loop induced modifications to the Newtonian potential can accumulate to levels testable in laboratory and astrophysical probes of gravity at short distances. In this work we systematically derive and constrain the impact of large dark sectors on precision tests of Newtons law, translating effective field theory predictions into the experimental language of Yukawa type deviations and inverse square law deformations. By mapping precision fifth force constraints onto bounds on species multiplicities and masses, we show that current and forthcoming experiments already impose nontrivial constraints on the size and structure of hidden sectors coupled only gravitationally. For truly massless hidden states, present data still permit multiplicities as large as 1e61, with modest spin dependence; for finite masses the constraints reduce to the familiar short range Yukawa parameterization. Our results provide a model independent framework for confronting dark sector scenarios with precision gravity data and clarify how non minimal scalar couplings, potential higher derivative poles at large species number, and Kaluza Klein towers fit within this picture. The approach is complementary to cosmological probes: Big Bang Nucleosynthesis and the Cosmic Microwave Background constrain relic abundances under specified production histories, whereas laboratory tests constrain the spectrum of light states irrespective of their cosmological population.

   hep-phastro-ph.HEgr-qchep-thJHEP(2026)·1 citation
8. 08*

   Searching for Dark Pions with the MoEDAL-MAPP Detector at the LHC

   Shafakat Arifeen🇨🇦 · Pierre-Philippe Ouimet🇨🇦 · James Pinfold🇨🇦 · Michael Staelens🇪🇸

   We investigate the potential for detecting pion-like dark matter within the framework of a Strongly Interacting Massive Particle (SIMP) model using the MoEDAL Apparatus for Penetrating Particles (MAPP) at the LHC. The model, motivated by Chiral Perturbation Theory, features milli-charged dark pions that couple to Standard Model particles via kinetic mixing with a dark photon. Production channels considered include Drell--Yan pair production and photon fusion via the Wess--Zumino--Witten term, the latter providing a distinctive three-body final state signature. Cross-sections are computed using MadGraph and WHIZARD for a range of dark pion masses, decay constants, and dark $Z$ boson masses. Sensitivity projections for MAPP-1 during the High-Luminosity LHC phase are presented under a background-free assumption, showing competitive reach into previously unexplored parameter space for milli-charged dark pseudoscalars. These results highlight the complementary role of MoEDAL-MAPP in probing dark sector models and motivate further detector-level simulations to refine exclusion limits.

   hep-phJHEP(2026)·1 citation
9. 09*

   Two-flavor chirally imbalanced quark matter beyond large $N_c$

   André G. da Silva🇧🇷 · Dyana C. Duarte🇧🇷 · Ricardo L. S. Farias🇧🇷 · Marcus Benghi Pinto🇧🇷 · Rudnei O. Ramos🇧🇷 · William R. Tavares🇧🇷

   We investigate a chirally imbalanced medium in the context of the two-flavor Nambu--Jona-Lasinio model using both the large-$N_c$ (LN) and beyond large-$N_c$ (BLN) approximations. To incorporate BLN effects, we consider the optimized perturbation theory (OPT) to the first nontrivial order, which includes two-loop (exchange) contributions. This procedure allows us to explicitly explore how finite $N_c$ corrections affect the thermodynamics as well as the phase diagram of chirally imbalanced quark matter. We then compare the results obtained with a sharp three-dimensional cutoff -- generically referred to as the traditional regularization scheme -- and with an alternative procedure called the medium separation scheme (MSS). In the first case, we observe that the pseudocritical temperature decreases as the chiral chemical potential increases, an effect dubbed inverse chiral catalysis. On the other hand, when considering the MSS regularization, which properly isolates the medium contributions from the vacuum, we find the opposite result. We show that the results obtained with MSS are consistent with well-established LQCD data in both the LN and BLN approximations. Finally, we suggest that to cope with the high-density limit, the standard OPT interpolation prescription must be modified with the inclusion of an extra variational parameter.

   hep-phhep-thnucl-thPRD(2025)·6 citations
10. 10*

    Revisiting the first-order QCD phase transition in dense strong interaction matter

    Yi Lu🇨🇳 · Fei Gao🇨🇳 · Yu-xin Liu🇨🇳

    We revisit the phase structure and thermodynamics of QCD in the low temperature and high density region, where a strong, first-order phase transition is expected beyond the critical end point. By solving the quark gap equation in the continuum QCD approach, we reveal the coexistence of the multi-phases both in the microscopic dynamics of chiral symmetry breaking and also in the thermodynamic observables, which manifests the existence of spinodal decomposition during the first-order QCD phase transitions. We also analyse the interface structure of the co-exist Nambu and Wigner phases in the isothermal process during the first-order transition. In particular, the interface tension and interface entropy density are extracted from the isothermal trajectories, which further allows for an analysis on the formation of nuclear bubble, including the bubble radius and its stability at different temperatures. Our predictions may serve as useful inputs for further investigations in heavy-ion physics or astrophysics research.

    hep-phhep-thnucl-th2 citations
11. 11*

    Lee--Yang edge singularities in Nonlocal Nambu--Jona-Lasinio Model

    Zong-shuai Zhang🇨🇳 · Yi Lu🇨🇳 · Yu-xin Liu🇨🇳

    We investigate the QCD phase diagram and the associated Lee--Yang edge singularities using the two-flavor nonlocal Nambu--Jona-Lasinio model extended to complex chemical potential. There exists a strong correlation between the chiral phase transition and the structure of the effective potential in the complex order parameter plane, serving as a criterion to differentiate crossover from first-order transitions. Typically, the Lee--Yang edge singularities can be understood as a generalization of the critical end-point (CEP) between crossover and first-order transitions, where the positive Nambu phase and the Wigner phase coalesce. We further analyze the scaling behavior near the CEP by extracting the critical exponent associated with the Lee--Yang singularities. Additionally, we confirm that the extrapolation of the Lee--Yang edge singularity trajectories provides an effective method of determining the CEP location, even at a small real chemical potential. This provides a viable method for exploring regions of the QCD phase diagram that remain inaccessible to lattice QCD.

    hep-phhep-thnucl-thPRD(2026)·2 citations
12. 12*

    The role of the soft scale for $J/\psi$ production in the transverse momentum dependent framework

    Marston Copeland🇺🇸 · Sean Fleming🇺🇸 · Reed Hodges🇺🇸

    We use vNRQCD to study power corrections in the $\mathrm{v}$ expansion due to soft gluon radiation during $J/\psi$ production at small transverse momentum. We categorize four new $J/\psi$ production operators that mediate the transition of perturbatively produced color-octet charm quark/anti-quark pairs to charm quarks in a ${}^3{S}_1^{[1]}$ state via soft gluon emission. We then use Soft Collinear Effective Theory and vNRQCD to derive a factorization theorem for $J/\psi$ production in SIDIS in terms of the gluon transverse momentum dependent (TMD) PDFs in the proton and new objects which we call TMD soft transition functions. We show that the TMD soft transition function leads in the $\mathrm{v}$ power-counting with respect to the color-octet TMD shape functions that have been used in previous studies of $J/\psi$ production at small transverse momentum.

    hep-phhep-thnucl-th7 citations
13. 13*

    The $R^2$-Higgs inflation: $R^3$ contribution and preheating after ACT and SPT data

    Tanmoy Modak🇮🇳

    The $R^2$-Higgs inflation is one of the simplest yet best-fit models consistent with Planck data. The higher spectral index $n_s$ recently reported by the combined cosmic microwave background (CMB) data from the Atacama Cosmology Telescope (ACT), South Pole Telescope (SPT), and Planck, along with baryonic acoustic oscillation data from the Dark Energy Spectroscopic Instrument (DESI), disfavors the single-field-like regime of $R^2$-Higgs inflation at approximately $2\sigma$. Following a doubly covariant formalism, we show that the $R^2$-Higgs inflation, when modified by a dimension-six $R^3$ term, can account for the high $n_s$ reported by CMB+BAO. In this regard, we find that preheating may play a pivotal role. We also show that if the nonminimal coupling between the Ricci scalar $R$ and the Higgs field is $\mathcal{O}(10)$, then preheating via the production of Higgs quanta may help explain the reported observations.

    hep-phastro-ph.COgr-qcPRD(2025)·23 citations
14. 14*

    Wave-particle duality and entanglement in neutrino oscillation

    Rajrupa Banerjee🇮🇳 · Pratidhwani Swain🇮🇳 · Prasanta K. Panigrahi🇮🇳 · Sudhanwa Patra🇮🇳

    We investigate wave--particle--entanglement complementarity in three-flavor neutrino oscillations within a quantum information--theoretic framework. Treating neutrino flavor evolution as an open quantum system and explicitly accounting for detector--propagation correlations, we extend the conventional wave--particle duality relation to a triality relation involving predictability, visibility, and entanglement. Using reduced density matrices and I-concurrence as a quantitative measure of entanglement, we demonstrate that the total information content of the system satisfies the relation ${\mathcal{P}}^2+{\mathcal{V}}^2+{\mathcal{E}}^2=1$. While predictability and visibility exhibit the expected complementary behavior, we show that entanglement encodes additional wave-like information that is not captured by visibility alone. We apply our formalism to realistic long-baseline neutrino experiments, namely \textsf{DUNE} and \textsf{T2K}, and find that at the first oscillation maximum, a simultaneous characterization of the particle-like and wave-like nature of neutrinos becomes possible through the combined measurement of predictability and entanglement. Our results provide a unified operational interpretation of neutrino oscillations and highlight the role of quantum correlations in extending wave--particle duality to multipartite systems.

    hep-phNPB(2026)·2 citations
15. 15*

    Confronting the production mechanisms of nuclei with deuteron and proton-triggered balance functions

    Sushanta Tripathy🇸🇪 · Peter Christiansen🇸🇪

    In ultra high-energy collisions, nuclei with very low binding energies are not expected to survive the dense and hot final state environment. The traditional view has therefore been that nuclei form via coalescence after the hot environment has dissipated. However, statistical thermal models, where hadrons are produced from a fireball at thermal equilibrium, can describe the relative abundances of light nuclei in pp and heavy-ion collisions at the LHC equally well. In this paper we investigate if balance functions triggered by protons and deuterons can be used to distinguish between the two production mechanisms. The coalescence model is investigated using PYTHIA, while the statistical thermal model is examined using the Thermal FIST package. We find that for both models the same simple relation between proton and deuteron triggered balance functions is applicable. However, there is a striking difference between the two models when the transverse momentum of trigger particles is varied. This dependence offers a promising observable to discriminate between the two production scenarios that goes beyond nuclei production. Furthermore, we find that deuteron-meson balance functions vanish identically for both models due to baryon number conservation and isospin symmetry.

    hep-phhep-exnucl-thEPJC(2026)·2 citations
16. 16*

    Two-sector leptogenesis in a two-Higgs-doublet model with spontaneous CP violation

    Debashree Priyadarsini Das🇮🇳 · Joy Ganguly🇮🇳 · Sasmita Mishra🇮🇳

    The extension of the Standard Model (SM) field content with one inert Higgs doublet (IHD) and three right-handed neutrinos (RHNs) is a well-motivated approach. The key advantages of the model include the appearance of a weakly interacting massive particle (WIMP) like dark matter (DM) candidate from the neutral component of the IHD, along with the plausible explanation of the sub-eV mass range of SM neutrinos via the radiative seesaw mechanism. Additionally, the decay of RHNs can contextualize the baryon asymmetry of the universe via leptogenesis and is intricately connected to CP violation. Also, given the ongoing searches for light scalars at various experimental facilities, the extended Higgs sector of the model continues to be at the forefront. However, this scotogenic framework encounters a deficiency in providing the observed amount of relic density for a particular mass range $\sim (80-500)$ GeV of its DM candidate, hence requiring further augmentation. Also, the WIMP scenarios have not yet resulted in conclusive hints at the direct detection experiments. In this context, our work is based on further extension of the above Scotogenic model by a dark sector. Additionally, considering the cosmic coincidence aspect, we operate within the framework of two-sector leptogenesis. To have a predictive flavor structure in the visible sector, we impose $A_4$ symmetry. Also, we adhere to spontaneous CP violation via complex vacuum expectation value of the falvon field, leading to a situation where there is only one CP-violating phase as a common connection between the visible and dark sectors. In our analysis, we find for the lightest RHN mass $\sim 10^{10}$ GeV, our results are in good agreement with the observational ratio of relic densities, i.e., ${\Omega }_{\mathrm{DM}}/{\Omega }_{\mathrm{b}}\sim 5$ for a few GeV range of mass of the dark sector DM candidate.

    hep-ph0 citations
17. 17*

    Charge asymmetry in the process $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0\gamma$

    I.V. Obraztsov🇷🇺 · A.S. Rudenko🇷🇺 · A.I. Milstein🇷🇺

    The charge asymmetry in the process $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0\gamma$ is studied for photons with energies $\nu \ll \sqrt{s}$. The longitudinal polarization of electrons (positrons) is taken into account. The asymmetry arises due to interference of the amplitudes for production of pion states with opposite $C$ parities. The contribution of $a_1^0(1260)$ meson in the intermediate state to the charge asymmetry is discussed. This contribution is not the leading one, however it is not negligible. It is shown that the charge asymmetry can reach several tens of percent.

    hep-phhep-exPRD(2025)·0 citations
18. 18*

    A novel force from the curved field space: Lepton flavor violation and $g-2$

    Cao H. Nam🇻🇳

    We find that the nonzero curvature extension of the field space for the charged leptons induces a peculiar force, leading to an elegant and simple mechanism for generating the charged lepton flavor violation (CLFV) and their anomalous magnetic moment, which has not been explored in the literature. This novel force corrects the electromagnetic vertex, leading to an effective coupling which is flavor off-diagonal at tree level. Consequently, it yields the CLFV decays with a very strongly amplified sensitivity, allowing for the CLFV probes in the small flavor-violating parameter region which is out of reach of the previous models. We point out a new type of contribution for the anomalous magnetic moment of the charged leptons, coming from the electric form factor corrected by the force emerging from the curved field space.

    hep-phhep-th0 citations
19. 19*

    Searching for HWW Anomalous Couplings with Simulation-Based Inference

    Marta Silva🇵🇹 · Ricardo Barrué🇵🇹 · Inês Ochoa🇵🇹 · Patricia Conde Muíño🇵🇹

    Understanding the source of the universe's asymmetry between matter and antimatter is one of the major open questions in particle physics. In this work, the sensitivity of novel machine-learning-based inference techniques to CP-odd and CP-even $HWW$ anomalous couplings is studied in the $WH\to \ell \nu b\bar{b}$ channel ($\ell =e,\mu$), within the Standard Model Effective Field Theory (SMEFT) framework. Two machine-learning simulation-based inference (SBI) methods are explored: a per-event likelihood-ratio estimator, which directly approximates the ratio of probability densities between competing hypotheses, is benchmarked against a per-event optimal-observable estimator optimized for sensitivity to the parameters of interest. Both approaches are also compared to traditional summary statistics, in this case histograms of kinematic and angular observables, as commonly used in experimental analyses. SBI methods provide tighter constraints than one-dimensional summary statistics, though their performance is comparable to two-dimensional histogram analysis. The optimal-observable approach remains promising for its ability to probe multiple couplings simultaneously. Restricting the analysis to a region of high $S/B$ also enhances sensitivity to CP-odd operators while preserving sensitivity to CP-even operators, which histogram analyses often lose. Although the likelihood-ratio estimator sometimes struggles with likelihood minima and shapes, optimisations that target its robustness could make it more sensitive than both the optimal-observable estimator and the histogram method. These results underscore the potential of advanced simulation-based inference techniques, encouraging further exploration with LHC Run 3 data to surpass current ATLAS and CMS sensitivities.

    hep-phhep-exPRD(2026)·6 citations
20. 20*

    On the renormalization-group analysis of the SM: loops, uncertainties, and vacuum stability

    A.V. Bednyakov🇷🇺 · A.S. Fedoruk🇷🇺 · D.I. Kazakov🇷🇺

    Renormalization-group equations (RGE) is one of the key tools in studying high-energy behavior of the Standard Model (SM). We begin by reviewing one-loop RGE for the dimensionless couplings of the SM and proceed to the state-of-the-art results. Our study focuses on the RGE solutions at different loop orders. We compare not only the standard (``diagonal'') loop counting when one considers gauge, Yukawa, and scalar self-coupling beta functions at the same order but also ``non-diagonal'' ones, inspired by the so-called Weyl consistency conditions. We discuss the initial conditions for RGE (``matching'') for different loop configurations and study the uncertainties of running couplings both related to the limited precision of the experimental input (``parametric'') and the missing high-order corrections (``theoretical''). As an application of our analysis we also estimate the electroweak vacuum decay probability and study how the uncertainties in the running parameters affect the latter. We argue that ``non-diagonal'' beta functions, if coupled with a more consistent ``non-diagonal'' matching, lead to larger theoretical uncertainty than ``diagonal'' ones.

    hep-phPRD(2026)·5 citations
21. 21*

    Probing Heavy Dark Matter in Red Giants

    Sougata Ganguly🇰🇷 · Minxi He🇰🇷 · Chang Sub Shin🇰🇷 · Oscar Straniero🇮🇹 · Seokhoon Yun🇰🇷

    Red giants (RGs) provide a promising astrophysical environment for capturing dark matter (DM) via elastic scattering with stellar nuclei. Captured DM particles migrate toward the helium-rich core and accumulate into a compact configuration. As the DM population grows, it can become self-gravitating and undergo gravitational collapse, leading to adiabatic contraction through interactions with the ambient medium. The resulting energy release, through elastic scattering and, where relevant, DM annihilation during collapse, locally heats the stellar core and can trigger helium ignition earlier than that predicted by standard stellar evolution. We analyze the conditions under which DM-induced heating leads to runaway helium burning and identify the critical DM mass required for ignition. Imposing the observational constraint that helium ignition must not occur before the observed luminosity at the tip of the RG branch, we translate these conditions into bounds on DM properties. Remarkably, we find that RGs are sensitive to DM, particularly with masses around $10^{11}\mathrm{GeV}$ and spin-independent scattering cross sections near $10^{-37}{\mathrm{cm}}^2$, which is comparable to the reach of current terrestrial direct detection experiments. Noteworthy, observations of RG stars provide a unique probe for high-mass and large-cross-section DM, a regime that remains currently inaccessible to direct detection experiments.

    hep-phastro-ph.HEastro-ph.SRPRD(2026)·1 citation
22. 22*

    Entanglement entropy, Monte Carlo event generators, and soft gluons DIScovery

    Martin Hentschinski🇲🇽 · Hannes Jung🇧🇪 · Krzysztof Kutak🇵🇱

    We study entropy production in Deep Inelastic Scattering using Monte Carlo simulations. We show that the dominant contribution to entropy is due to soft gluons. This contribution is usually neglected in standard Monte Carlo approaches, since it does not affect hadronic spectra. However, it is relevant for entropy and multiplicity distributions, as we demonstrate with explicit calculations. We further show that as one includes soft gluons, making the Monte Carlo parton distributions closer to inclusive PDFs, the resulting entropy starts to grow with decreasing x. This provides further evidence that the bulk of the measured entropy originates from initial-state effects.

    hep-phhep-thquant-phPRD(2026)·11 citations
23. 23*

    Boomerang mechanism explaining the excess radio background

    Bhupal Dev🇺🇸 · Pasquale Di Bari🇬🇧 · Ivan Martinez-Soler🇬🇧 · Rishav Roshan🇬🇧

    We propose a boomerang mechanism for the explanation of the excess radio background detected by ARCADE 2. In an early stage of the Universe, at a temperature $T$ in the range $\sim 0.1\mathrm{keV}$--$1\mathrm{MeV}$, a fraction of relic neutrinos is resonantly converted into dark neutrinos by mixing induced by a pre-existing lepton asymmetry. Dark neutrinos decay much later into a dark-standard photon state and a dark fermion, with a lifetime longer than the age of the Universe, as required by a solution to the excess radio background. This scenario circumvents the upper bound on the neutrino magnetic moment but still implies a testable lower bound.

    hep-phastro-ph.COPRD(2026)·6 citations
24. 24*

    Probing a Light Scalar Boson with a few-MeV Proton Beam Deep Underground

    Carlo Broggini🇮🇹 · Giuseppe Di Carlo🇮🇹 · Luca Di Luzio🇮🇹 · Denise Piatti🇮🇹 · Claudio Toni🇫🇷

    We propose to investigate the production of a light scalar boson $\varphi$ in low-energy proton-nucleus interactions using the 3.5 MV accelerator of the Bellotti Ion Beam Facility, located in the underground Gran Sasso National Laboratory. Nuclear reactions induced by a few-MeV proton beam on suitable target materials can act as a controlled source of $\varphi$ particles. Owing to the deep-underground location, the facility benefits from substantial cosmic-ray shielding, enabling searches for rare processes with minimal background. The produced $\varphi$ particles will be sought with large-volume, low-background detectors already operating or currently under construction at the Gran Sasso National Laboratory. This approach combines a tunable accelerator-based production mechanism with the exceptional sensitivity of underground rare-event searches, offering a novel avenue to probe light scalar bosons beyond the Standard Model.

    hep-phhep-exnucl-exPRD(2025)·0 citations
25. 25*

    Axion lines from nuclear de-excitations in galactic stellar populations

    Orion Ning🇺🇸 · Anupam Ray🇺🇸 · Benjamin R. Safdi🇺🇸

    We show that mono-energetic axions are produced in abundance through nuclear de-excitations in nearby galaxies such as M87, which is the central galaxy of the Virgo cluster, and the starburst galaxy M82. If the axion couples to both nucleons and photons and is ultralight, then monochromatic hard X-ray signatures are induced by the subsequent axion-to-photon conversion in the magnetic fields permeating these systems. We search for evidence of such signals using NuSTAR data, focusing specifically on the ${}^{57}$Fe de-excitation line at 14.4 keV, and we catalog other potentially relevant nuclear lines. We find no evidence for axions from M87 or M82 and set leading constraints on the combined axion-nucleon and axion-photon coupling at the level of $|g_{ann}\times g_{a\gamma \gamma }|\lesssim 1.1\times 10^{-22}$ GeV${}^{-1}$ in the limit $m_a\lesssim 10^{-10}$ eV, at 95% confidence.

    hep-phastro-ph.GAastro-ph.HEPRD(2026)·8 citations
26. 26*

    Testing Seesaw and Leptogenesis via Gravitational Waves: Majorana versus Dirac

    Anish Ghoshal🇵🇱 · Kazunori Kohri🇯🇵 · Nimmala Narendra🇮🇳

    We investigate the B-L gauge extension of the Standard Model that the Dirac seesaw mechanism with thermal Leptogenesis can be tested using the stochastic gravitational background (SGWB) emanating from a network of cosmic strings when B-L symmetry is broken. With right-handed neutrino mass lighter than the typical scale of grand unification, the B-L symmetry protecting the right-handed neutrinos leads to constraints on the Yukawa couplings for both Dirac and Majorana scenarios. Estimating the predicted gravitational wave background we find that future space-borne missions could probe the range concerning thermal Dirac Leptogenesis. In a comparative analysis between such probes of gravitational wave sourced from cosmic strings in Dirac and Majorana Leptogenesis in the B-L extension, based on the energy scales of the Leptogenesis, for instance, GW detectors will be able to probe the scale of Dirac Leptogenesis upto $10^9$ GeV, while for Majorana Leptogenesis it would be upto $10^{12}$ GeV.

    hep-phastro-ph.COhep-thPRD(2026)·2 citations
27. 27*

    On-shell Matrix Elements of the EMT Trace in Gauge Theories and Heavy Quark Masses

    Long Chen🇨🇳 · Zhe Li🇨🇳 · Marco Niggetiedt🇩🇪

    We present a novel diagrammatic proof of the identity between the forward matrix element of the energy-momentum-tensor (EMT) trace operator over a single particle's on-shell state and its perturbative pole mass to any loop orders in perturbative gauge theories (with gauge bosons and fermions), without appealing to any pre-laid operator renormalization conditions or Ward identities. The proof is based on the equation of mass-dimensional analysis in dimensional regularization, the topological properties of contributing Feynman diagrams and the on-shell renormalization condition. Considering for definiteness perturbative QED and QCD with at most one fermion kept massive, we have verified the aforementioned identity, up to three loops, for all elementary particles through direct computation of dimensionally-regularized matrix elements of the relevant bare operators. We observe interestingly that the trace-anomaly contribution seemingly contains all leading-renormalon effects (explicitly verified up to three loops), and we propose accordingly a new scheme- and scale-independent trace-anomaly-subtracted mass definition for heavy $t$-,$b$-,$c$-quarks and electrons. A list of amusing numbers is subsequently presented for the composition of their perturbative pole masses.

    hep-phhep-lathep-thPLB(2025)·7 citations
28. 28*

    Iterative HOMER with uncertainties

    Anja Butter🇩🇪 · Ayodele Ore🇩🇪 · Sofia Palacios Schweitzer🇩🇪 · Tilman Plehn🇩🇪 · Benoît Assi🇺🇸 · Christian Bierlich🇸🇪 · Philip Ilten🇺🇸 · Tony Menzo🇺🇸 · Stephen Mrenna🇺🇸 · Manuel Szewc🇺🇸 · Michael K. Wilkinson🇺🇸 · Ahmed Youssef🇺🇸 · Jure Zupan🇺🇸

    We present iHOMER, an iterative version of the HOMER method to extract Lund fragmentation functions from experimental data. Through iterations, we address the information gap between latent and observable phase spaces and systematically remove bias. To quantify uncertainties on the inferred weights, we use a combination of Bayesian neural networks and uncertainty-aware regression. We find that the combination of iterations and uncertainty quantification produces well-calibrated weights that accurately reproduce the data distribution. A parametric closure test shows that the iteratively learned fragmentation function is compatible with the true fragmentation function.

    hep-phhep-exSciPost Phys.(2026)·10 citations
29. 29*

    Prospects for toponium formation at the LHC in the single-lepton mode

    Benjamin Fuks🇫🇷 · Kaoru Hagiwara🇯🇵 · Kai Ma🇨🇳 · Léandre Munoz-Aillaud🇫🇷 · Ya-Juan Zheng🇯🇵

    We investigate the formation of toponium in the single-leptonic final state at the LHC. Our study builds on our recently proposed framework that incorporates the associated non-perturbative effects into Monte Carlo simulations through the Green's function of the non-relativistic QCD Hamiltonian and the re-weighting of hard-scattering matrix elements. This allows us to perform a phenomenological analysis that demonstrates that a statistically significant excess from toponium formation could already be accessible in Run~2 data. Moreover, our results highlight observables that provide handles for signal characterisation and establish the single-leptonic channel as a competitive and complementary avenue for the ongoing exploration of toponium signatures at colliders.

    hep-phhep-exPLB(2026)·10 citations
30. 30*

    The possibility to experimentally determine the structure of a fermionic vacuum in quantum electrodynamics

    V.P.Neznamov🇷🇺

    In the standard quantum electrodynamics (QED), the fermionic vacuum is a continuum of randomly created and annihilated virtual electron-positron pairs. In this case, in the strong electromagnetic fields, vacuum creation of real electron-positron pairs is possible. In particular, in the standard QED in a strong uniform electrical field, the Schwinger effect is implemented. Currently, there exist the QED versions with empty fermionic vacuum without fluctuations of creation and annihilation of virtual electron-positron pairs. These versions are the (QED)FW in the Foldy-Wouthuysen representation, the $(QED{)}_{KG}$ with spinor equations of the Klein-Gordon type, the $(QED{)}_{DN}$ with opposite signs in front of particle and antiparticle masses in Dirac equations and with the use of only states with positive energies in S-matrix elements. The latter relates to both real and virtual energy states. In this paper, we propose to carry out a set of experiments at colliders with collisions of heavy ions to determine the nature of the fermionic vacuum. The measurements of the emission of electron-positron pairs depending on the total charge of colliding ions $Z_{\Sigma }=146÷184$ show the structure of a fermionic vacuum in quantum electrodynamics.

    hep-phInt.J.Mod.Phys.A(2025)·0 citations
31. 31*

    Feynman-like parameterizations of (anti-)de Sitter Witten diagrams for all masses at any loop order

    Aidan Herderschee🇺🇸

    Computing correlation functions in curved spacetime is central to both theoretical and experimental efforts, from precision cosmology to quantum simulations of strongly coupled systems. In anti-de Sitter (AdS) and de Sitter (dS) space, the key observables, boundary correlators in AdS and late-time correlators in dS, are obtained via Witten diagram calculations. While formally analogous to flat-space Feynman diagrams, even tree-level Witten diagrams are significantly more complicated due to the structure of bulk propagators. Existing computational approaches often focus on scalars with a specific "conformal" mass, for which propagators simplify enough to permit the use of standard flat-space techniques. This restriction, however, omits the generic internal-line masses that arise in many cosmological and holographic settings. We present the Witten-Feynman (WF) parameterization, a general representation of scalar Witten diagrams in (A)dS as generalized Euler integrals. The WF framework applies in both position and momentum space, accommodates arbitrary internal and external masses, and holds at any loop order. It directly generalizes the familiar Feynman parameterization form of Feynman integrals, making it possible to import a broad range of amplitude techniques into the curved-space setting. We illustrate the method through two applications: a generalization of Weinberg's theorem on ultraviolet convergence and a series expansion technique that can yield explicit evaluations. Our results provide a unified computational tool for (A)dS boundary correlators, opening the door to more systematic calculations relevant for upcoming experiments and simulations.

    ↳ hep-thgr-qchep-phmath-ph+12 citations
32. 32*

    The 2020 Superburst of 4U 1608-522 and its impact on the accretion disk

    Tugba Boztepe🇹🇷 · Tolga Guver🇹🇷 · Elif Ece Devecioglu🇹🇷 · Julia Speicher🇺🇸 · Motoko Serino🇯🇵 · David R. Ballantyne🇺🇸 · Diego Altamirano🇬🇧 · Gaurava K. Jaisawal🇩🇰 · Mason Ng🇨🇦 · Andrea Sanna🇮🇹 · Can Gungor🇹🇷 · Wataru Iwakiri🇯🇵

    Superbursts are rare events observed from bursting neutron star low mass X-ray binaries. They are thought to originate from unstable burning of the thick layer of Carbon on the surface of the neutron star, causing the observed X-ray flashes to last several hours. Given their fluence it has long been thought that superbursts may have significant effects on the accretion flow around the neutron star. In this paper, we first present evidence for a new superburst observed from 4U 1608-522 by MAXI during the 2020 outburst, around 00:45 UTC on 16 July 2020. We compare some of the properties of this superburst and the underlying outburst with the events recorded on May 5 2005 by RXTE and most recently in 2025 by MAXI. We then present our spectral analysis of NICER and Insight-HXMT data obtained before and after the 2020 superburst event. Our results indicate that the inner disk temperature and the radius show a systematic evolution in the following few days, which may be related to the superburst. We show that the timescale of the observed evolution can not be governed by viscous timescales unless the viscosity parameter is unrealistically low.

    ↳ astro-ph.HEhep-phMNRAS(2025)·1 citation
33. 33*

    Updated bounds on ultra-light dark matter from the tiniest galaxies

    Simon May🇨🇦 · Neal Dalal🇨🇦 · Andrey Kravtsov🇺🇸

    The particle mass of dark matter (DM) was previously constrained using kinematics of ultra-faint dwarf galaxies to $m>3\times 10^{-19}\mathrm{eV}$. This constraint, which excludes the "fuzzy" range of ultra-light dark matter from comprising all of the DM, relies on an estimate of the heating rate from fuzzy dark matter (FDM) wave interference using linear perturbation theory. Here, we compare the results of this perturbative calculation to full Schrödinger-Poisson simulations of the evolution of star particles in FDM halos. This comparison confirms theoretical expectations that FDM heating is stronger in fully nonlinear simulations due to the formation of a dense central soliton whose fluctuations enhance gravitational perturbations, and that bounds on the DM particle mass using this perturbative method are indeed conservative. We also show that these bounds are not affected by possible tidal stripping, since for dwarf satellites like Segue 1, the tidal radius is much larger than the observed size of the galaxy. We further show that the constraints on the mass cannot be evaded by invoking DM self-interactions, due to constraints on the self-interaction from large-scale structure. Lastly, we show that if the recently discovered system Ursa Major III/UNIONS I is a galaxy, the observed properties of this object strengthen the lower bound on the DM mass by over an order of magnitude, to $m>8\times 10^{-18}\mathrm{eV}$, at 95% confidence. This constraint could further be strengthened considerably by more precise measurements of the size and velocity dispersion of this and other similar galaxies, and by using full Schrödinger-Poisson simulations.

    ↳ astro-ph.COastro-ph.GAhep-ph32 citations
34. 34*

    Towards Precise Simulations and Inference for the Neutron EDM

    Skyler Degenkolb🇩🇪 · Luigi Favaro🇧🇪 · Peter Fierlinger🇩🇪 · Jennifer Franz🇩🇪 · Husain Manasawala🇩🇪 · Tilman Plehn🇩🇪

    Precision measurements of neutron properties, like its permanent electric dipole moment, rely on understanding complex experimental setups in detail. We show how the properties of stored and transported ultracold neutron ensembles can be simulated reliably. In a second step, we illustrate how they can be used for simulation-based inference of the parameters associated with underlying physics processes such as neutron capture or beta decay. Our proof of principle for simulation-based inference confronts a longstanding challenge with ultracold neutrons: low measurement statistics coupled with a complex apparatus.

    ↳ nucl-thhep-phnucl-ex0 citations
35. 35*

    Observational challenges to holographic and Ricci dark energy paradigms: Insights from ACT DR6 and DESI DR2

    Peng-Ju Wu🇨🇳 · Tian-Nuo Li🇨🇳 · Guo-Hong Du🇨🇳 · Xin Zhang🇨🇳

    Recent studies suggest that dark energy may be dynamical rather than being a mere cosmological constant $\Lambda$. In this work, we examine the viability of two physically well-motivated dynamical dark energy models -- holographic dark energy (HDE) and Ricci dark energy (RDE) -- by confronting them with the latest observational data, including ACT cosmic microwave background anisotropies, DESI baryon acoustic oscillations, and DESY5 supernovae. Our analysis reveals a fundamental tension between early- and late-universe constraints within both frameworks: ACT favors a quintom scenario where the dark energy equation of state evolves from $w>-1$ at early times to $w<-1$ at late times, while DESI+DESY5 exhibits a distinct preference for quintessence where $w>-1$ across cosmic evolution. Critically, the RDE model fails to provide a coherent description of cosmic evolution, as it manifests severe tensions (exceeding $10\sigma$ significance) between early- and late-universe parameter reconstructions. In addition, Bayesian evidence disfavors both models relative to the $\Lambda$CDM model. Our findings statistically exclude the original HDE and RDE models and uncover a severe discrepancy between early- and late-universe observations described by them, leading to the conclusion that the HDE and RDE models can be ruled out by current observational data.

    ↳ astro-ph.COgr-qchep-phhep-thCPC(2026)·36 citations
36. 36*

    Origin of nucleon mass in the light of PSR J0614-3329 with quark-hadron crossover

    Bikai Gao🇯🇵 · Yuk-Kei Kong🇯🇵 · Yong-Liang Ma🇨🇳

    The recent NICER observation of PSR J0614-3329, revealing the smallest reliably measured neutron star radius of $R=10.29_{-0.86}^{+1.01}$ km at mass $M=1.44_{-0.07}^{+0.06}{M}_{\odot }$, provides an unprecedented constraint on the equation of state of dense matter. We investigate the implications of this measurement for the origin of nucleon mass within the parity doublet model framework, which naturally incorporates both chiral variant and chiral invariant mass components. We construct unified equations of state by employing the parity doublet model with isovector scalar meson $a_0(980)$ for hadronic matter up to twice nuclear saturation density, smoothly connected to a Nambu-Jona-Lasinio-type quark model at higher densities through a crossover transition. By systematically varying the chiral invariant mass $m_0$ and quark matter parameters, we determine which values simultaneously satisfy all current astrophysical constraints, including gravitational wave observations from GW170817, NICER measurements of several pulsars, and the existence of two-solar-mass neutron stars. The inclusion of PSR J0614-3329 dramatically refines the allowed range of the chiral invariant mass from the previous constraint of $580\text{MeV}\lesssim m_0\lesssim 860\text{MeV}$ to $800\text{MeV}\lesssim m_0\lesssim 860\text{MeV}$, raising the lower bound by approximately 220 MeV. This result indicates that the chiral invariant mass must constitute at least 85\% of the nucleon mass, challenging the traditional picture of nucleon mass generation through spontaneous chiral symmetry breaking alone and highlighting the importance of gluon condensation and other non-chiral mechanisms.

    ↳ nucl-thastro-ph.HEhep-phPRD(2025)·13 citations
37. 37*

    Aspects of the Black Hole Interior Volume and Entropy

    Shad Ali🇨🇳

    The basic and conceptual notion of this work starts from the recent investigations of Marios Christodoulou and Carlo Rovelli (CR) in their paper entitled ''How big is a black hole?''. This work is related to the black hole interior volume and the entropy by Baocheng Zhang. In CR work, a spherically symmetric Schwarzschild black hole is considered and defines the interior volume, as the volume inside a sphere $S$ is the maximal proper volume of a space-like spherically symmetric $3d$ hypersurface bounded by the sphere $S$. Using this definition, they found the interior volume of a black hole is proportional to the advanced time. This is the main characteristic of this formulation. Which means that a black hole could store a large amount of infalling information. Using this special property, one can prob the nature of Hawking radiation emitted by a black hole. They also extend their result to the charged static black hole and found a consistent result. Their numerical analysis showed that the special character of this formulation is that the volume linearly increases with advancing time. Later, the CR work is followed by Baocheng Zhang, who investigated the entropy of scalar quantum modes in the interior of the Schwarzschild Black hole. He found the entropy of scalar quantum modes in the interior of Black hole is proportional to the lack hole surface area. The proportionality constant is found to be less than unity, which means that the interior entropy is less as compared to the Bekenstein Hawking entropy (horizon entropy). Note that these analyses are only applicable for black holes with mass greater than the Planck mass. If massless than Planck's mass, then one needs to understand the uncertainty relation.

    ↳ gr-qchep-phhep-thmath-ph+10 citations
38. 38*

    Suppression of dynamical momentum-space shell by chiral symmetry

    Bikai Gao🇯🇵 · Michał Marczenko🇵🇱

    We investigate the appearance of quark degrees of freedom in dense isospin-symmetric nuclear matter. We employ the parity doublet model to incorporate chiral dynamics. Specifically, we contrast quarkyonic matter, in which quarks occupy states above the nucleon Fermi surface, with baryquark matter, in which quarks populate states inside the nucleonic Fermi sea. We find that while baryquark matter is generally energetically favored over quarkyonic matter, the self-consistent treatment of the momentum-space shell reveals that purely hadronic matter provides the lowest free energy up to densities well beyond nuclear saturation. Consequently, the contribution of quarks is not relevant within the model's domain of applicability, even though chiral symmetry becomes restored. This demonstrates that the onset of quark degrees of freedom and the restoration of chiral symmetry need not coincide.

    ↳ nucl-thhep-phPRC(2026)·2 citations
39. 39*

    Recent progress on charmed hadron interactions from lattice QCD

    Yan Lyu🇯🇵

    Recent years have witnessed rapid progress in charmed hadron physics, driven by numerous experimental discoveries of exotic states such as $T_{cc}^{+}$ and $P_c$. These findings have highlighted the importance of understanding charmed hadron interactions. With significant advances in theory and computation, lattice QCD has become a reliable tool for studying nonperturbative dynamics of low-energy QCD. In this talk, I review recent lattice QCD studies of charmed hadron interactions, focusing on three representative systems: $D^{\ast }$-$D$, $N$-$c\bar{c}$, and ${\Omega }_{ccc}$-${\Omega }_{ccc}$.

    ↳ hep-lathep-phnucl-thPoS(2026)·1 citation
40. 40*

    Amplified capture rate of dark matter in compact binaries and constraints on bosonic dark matter from GW170817

    János Takátsy🇭🇺 · Lorenz Zwick🇩🇰 · David O'Neill🇩🇰 · Johan Samsing🇩🇰

    The accretion of dark matter (DM) onto compact objects and the potential gravitational collapse of neutron stars due to this accretion has become a promising indirect probe of DM properties, complementing terrestrial experiments. We show that the accretion flux of DM on stellar objects is amplified in binary systems due to the complex gravitational interaction of said particles with the binary. We perform few-body Monte Carlo simulations to show that this amplification factor is $\sim 4-5$ for circular binaries, small DM velocity dispersions and mass ratios $q\gtrsim 0.3$. We use this factor to improve previous constraints on the scattering cross section of non-annihilating bosonic DM with baryonic matter, and derive upper bounds on this cross section from the observation of the binary NS merger associated with GW170817. We also show that the maximally accretable mass fraction of DM by binary NSs is $\lesssim 10^{-3}$, even for extreme DM densities only possible in DM spikes, due to the dynamical friction exerted by the ambient DM.

    ↳ astro-ph.HEgr-qchep-phPRD(2026)·3 citations
41. 41*

    Two-loop vacuum polarization in a Coulomb field

    S. A. Volkov🇩🇪 · V. A. Yerokhin🇩🇪 · Z. Harman🇩🇪 · C. H. Keitel🇩🇪

    The leading-order two-loop vacuum-polarization potential, linear in the Coulomb field of a nucleus, was first derived in the seminal 1955 work of Källén-Sabry. The higher-order two-loop vacuum-polarization corrections, however, have remained unknown until now. In this work, we compute Coulomb corrections to the Källén-Sabry potential, specifically those involving three, five, and seven Coulomb interactions inside the vacuum-polarization loop. The potentials are evaluated in momentum space and subsequently used to calculate one-electron energy shifts. Our results drastically reduce the theoretical uncertainty of the two-loop vacuum-polarization contribution to transition energies, which is required for next-generation tests of bound-state QED in heavy one and few-electron ions as well as for the determination of nuclear charge radii.

    ↳ physics.atom-phhep-phPRA(2025)·4 citations
42. 42*

    Structure of renormalization constants for theories with multiple couplings in the MS-like subtraction schemes

    Gleb Kovyrshin🇷🇺 · Nikolai Meshcheriakov🇷🇺 · Victoria Shatalova🇷🇺 · Konstantin Stepanyantz🇷🇺

    For theories with multiple couplings we construct simple expressions for the four-dimensional (or, in general, integer-dimensional) renormalization constants assuming that all divergences are logarithmical. These expressions allow relating all coefficients at $\epsilon$-poles, logarithms, and (if exist) mixed terms to the coefficients of the renormalization group functions in any order of the perturbation theory for MS-like renormalization prescriptions. The result admits such a formulation in that $\epsilon$-poles and $\ln \Lambda /\mu$ enter on the same footing. For theories with two and three couplings we present explicit expressions for the pole/logarithm structure of renormalization constants in the lowest orders of the perturbation theory. They are verified by comparisons with the two-loop explicit calculation for $\mathcal{N}=1$ SQCD+SQED and also with the previously known three-loop calculations for the ${\phi }^4$-theory with two couplings.

    ↳ hep-thhep-phNPB(2026)·2 citations
43. 43*

    Wigner function of a rigidly rotating and magnetized QED plasma

    M. Kiamari🇮🇷 · N. Sadooghi🇮🇷

    We determine the Wigner function of a rigidly rotating quantum electrodynamics (QED) plasma in the presence of a constant magnetic field by utilizing the Riemannian normal coordinate approximation, which has been previously proposed in the literature. In this approach, the angular velocity appears only in a specific phase factor, allowing us to compute the point-split fermion two-point correlation function in flat spacetime. To ensure that the fermion correlation function is gauge invariant, we introduce a background gauge field that is fixed to produce a constant magnetic field. Using this Wigner function, we derive the energy-momentum tensor for this medium, which consists of both diagonal and off-diagonal components. By comparing our results with the energy-momentum tensor of an ideal spinful and vortical magnetized fluid, we establish a connection between these components and thermodynamic quantities, such as energy density and different types of pressure. We demonstrate that rigid rotation leads to pressure anisotropy in plasma. Additionally, we compute the associated vector and axial vector currents for this medium, utilizing the previously presented Wigner function. Our results are consistent with existing literature on the subject.

    ↳ nucl-thgr-qchep-phhep-th3 citations
44. 44*

    Gluon Condensate via Dirac Spectral Density: IR Phase, Scale Anomaly and IR Decoupling

    Ivan Horváth🇨🇿

    Quark and gluon scalar densities, $⟨\bar{\psi }\psi ⟩$ and $⟨F^2⟩$, reflect the degree of scale-invariance violations in SU(N) gauge theories with fundamental quarks. It is known that $⟨\bar{\psi }\psi ⟩$ can be usefully scale-decomposed via spectral density $\rho (\lambda )$ of Dirac modes. Here I give such formula for $⟨F^2⟩$, which reveals that gluon condensate is a strictly UV quantity. For the recently-found IR phase [1,2], where the infrared (IR) degrees of freedom separate out and become independent of the system's bulk, it implies that $⟨F^2⟩$ due to this IR part vanishes. Its glue thus doesn't contribute to scale anomaly of the entire system and is, in this sense, scale invariant consistently with the original claim. Associated formulas are used to define IR decoupling of glue, which may serve as an alternative indicator of IR phase transition. Using the simplest form of coherent lattice QCD, we express the effective action of full QCD entirely via Dirac spectral density.

    ↳ hep-lathep-phhep-thnucl-thPRD(2025)·1 citation
45. 45*

    Color-superconducting quarkyonic matter

    Christoph Gärtlein🇵🇹 · Oleksii Ivanytskyi🇵🇱 · Violetta Sagun🇬🇧 · Ilídio Lopes🇵🇹

    We explore the role of color superconductivity in quarkyonic matter under the conditions of color and electric neutrality at $\beta$- and strong equilibrium, as relevant for neutron stars. By explicitly incorporating the color-superconducting pairing gap into the phenomenological model of a smooth transition from hadron to quark matter, we extend the known quarkyonic framework to include this essential aspect relevant at high densities. The momentum dependence of the pairing gap, motivated by the running of the QCD coupling and introduced similarly to chiral quark models with nonlocal interaction, is a novel element of the model that is crucial for enabling the simultaneous onset of all color-flavor quark states in the presence of color superconductivity. While asymptotically conformal behavior of the present model is ensured by construction, we demonstrate that reaching the conformal limit in agreement with the predictions of perturbative QCD is provided by the proper momentum dependence of the thickness of the hadron shell in momentum space. We employ the flexible meta-modeling approach to nuclear matter, analyzing the structure of the hadron shell in momentum space and focusing on the effects of color superconductivity in quarkyonic matter. Similar to the effects induced by the onset of the quarkyonic phase, color superconductivity leads to stiffening of the equation of state of the NS matter. This causes a significant impact on observable properties of neutron stars, which are analyzed and compared to recent astrophysical and theoretical constraints. We argue that the developed model of color-superconducting quarkyonic matter provides a new, consistent tool for studying the scenario of smooth quark-hadron transition in NSs.

    ↳ nucl-thastro-ph.HEhep-phPRD(2026)·8 citations
46. 46*

    Probing dense environments around Sgr A* with S-stars dynamics

    Giovanni Maria Tomaselli🇺🇸 · Andrea Caputo🇨🇭

    The orbits of stars around Sgr A*, the Milky Way's supermassive black hole, provide a unique laboratory for testing its environment with unprecedented precision. In this work, we compute the apsidal precession induced by extended matter distributions through Lagrange's equations and compare it with the measured precession of S2, reproducing and extending GRAVITY's constraints. In particular, we push bounds on boson clouds to larger gravitational couplings $\alpha$ and to the second-fastest superradiant mode. We also show that environments with mass of order $1\%$ of Sgr A* drive stellar orbits to decay by dynamical friction within a few Myr. The inner star cluster is however efficiently replenished, masking this effect observationally. We also show that orbital resonances from boson clouds have no impact on relevant timescales. While S2 currently provides the cleanest dataset, our framework is readily applicable to other stars that we identify as particularly promising, whose orbits will be measured with increasing accuracy, opening up new opportunities to probe the environment of Sgr A*.

    ↳ astro-ph.GAgr-qchep-phPRD(2026)·13 citations
47. 47*

    Towards a Heterotic Axiverse

    Jacob M. Leedom🇨🇿 · Margherita Putti🇩🇪 · Alexander Westphal🇩🇪

    In this paper we initiate a broad study of some central properties of the string axiverse arising from Calabi-Yau compactifications of the perturbative heterotic $E_8\times E_8$ theory. Along this road toward a heterotic axiverse, we characterize the generic structure of the axion mass spectrum and the effective couplings of the non-QCD heterotic axions to Abelian and non-Abelian gauge fields and discuss their implications for cosmology, particle phenomenology, and the QCD axion quality problem. We also provide arguments that the heterotic axion masses are bounded from below much more strongly than, for example, the spectrum in type IIB compactifications.

    ↳ hep-thastro-ph.COhep-phJHEP(2026)·17 citations
48. 48*

    Tracing the Neutrino-Induced Phase Shift in the 21-cm Spectrum

    Gabriele Montefalcone🇺🇸 · Hector Afonso G. Cruz🇺🇸 · Julian B. Munoz🇺🇸 · Ely D. Kovetz🇮🇱 · Marc Kamionkowski🇺🇸

    We study the phase shift that free-streaming neutrinos imprint on the 21-cm power spectrum during cosmic dawn, computing for the first time its effect on both density- and velocity-induced acoustic oscillations. Neutrinos are known to generate a characteristic phase shift in the acoustic oscillations of the photon-baryon plasma before recombination, a signature already detected in the cosmic microwave background (CMB) as well as the spectrum of baryon acoustic oscillations (BAOs) extracted from galaxy surveys. We show that in the 21-cm signal this phase shift is distinct from that observed in the CMB and BAO spectra, exhibiting a characteristic mode and redshift dependence arising from the additional contribution of the so-called velocity acoustic oscillations (VAOs), sourced by the baryon-dark matter relative velocities. Our results establish the phase of acoustic oscillations in the 21-cm spectrum as a promising new avenue for probing free-streaming light relics at cosmic dawn, complementary to existing CMB and BAO measurements.

    ↳ astro-ph.COhep-phhep-thPRD(2026)·8 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.