Mon·Nov 24, 2025Monday·November 24, 2025

1. 01*

   Radiative neutrino mass generation and dark matter through vectorlike leptons

   Mohamed Amin Loualidi🇦🇪 · Salah Nasri🇦🇪 · Maximiliano A. Rivera🇨🇱

   This study presents a radiative three-loop model for neutrino mass generation, employing an asymmetric Yukawa coupling between two new scalar $SU(2{)}_L$ doublets and vectorlike lepton doublets. Dark matter candidates arise from one of the scalar doublets and contribute to neutrino mass generation through the mass splitting between its neutral components. The singly charged scalars are also essential for neutrino mass, with the charged states of the two doublets mixing with one another. A single generation of vectorlike leptons yields two nonzero neutrino masses as a consequence of the asymmetric Yukawa combinations entering the neutrino mass matrix. The model is tested against dark matter phenomenology, neutrino mass and mixing data, and the charged lepton flavor-violating process $\mu \to e\gamma$, showing compatibility with current bounds and leading to experimentally accessible predictions.

   hep-phPRD(2026)·0 citations
2. 02*

   Competition of ${\chi }_c(2P)$ quarkonia and continuum in $e^{+}{e}^{-}\to e^{+}{e}^{-}D\bar{D}$

   Izabela Babiarz🇵🇱 · Piotr Lebiedowicz🇵🇱 · Wolfgang Schäfer🇵🇱 · Antoni Szczurek🇵🇱

   We discuss the production of $D\bar{D}$ pairs in $e^{+}{e}^{-}$ collisions, where $D$ refers to either $D^0$ or $D^{+}$. The continuum mechanism with the $t/u$-channel vector-meson $D^{\ast }$ exchanges are considered. The results of the calculation depend on the parameter of the off-shell form-factor for the virtual $D^{\ast }$ mesons. The $D^{\ast }D\gamma$ coupling constants are found from the $D^{\ast }\to D\gamma$ decays. We find relatively large contribution for the $D^0{\bar{D}}^0$ channel and much smaller contribution in the $D^{+}{D}^{-}$ channel. In the second case we consider also the $D^{\pm }$ exchanges. We conclude that the bump at $M_{D^0{\bar{D}}^0}=3.8$ GeV observed by the Belle and BaBar Collaborations has rather continuum origin than it corresponds to the broad resonance ${\chi }_{c0}(3860)$. We discuss also production of the ${\chi }_{c2}(3930)$ resonance which is a candidate for the ${\chi }_{c2}(2P)$ state. This state can decay into both $D\bar{D}$ channels, however the branching fractions are not well known at present. From a comparison of our model results to the BaBar data we find $B({\chi }_{c2}(3930)\to D\bar{D})=0.58\pm 0.13$ using the two-photon width ${\Gamma }_{\gamma \gamma }=0.544$ keV (obtained for the Buchmüller-Tye potential) evaluated within the light-front approach (NRQCD limit). Our finding of ${\Gamma }_{\gamma \gamma }\times B({\chi }_{c2}(3930)\to D\bar{D})=0.32\pm 0.07$ keV is close to the Belle and BaBar results. Realistic predictions of the differential distributions in several variables and integrated cross-sections are given for the Belle II kinematics.

   hep-phhep-exPLB(2026)·1 citation
3. 03*

   Next-to-leading order analysis of $J/\psi +\gamma$ production in photon-photon collisions at CEPC

   Ying-Zhao Jiang🇨🇳 · Zhan Sun🇨🇳

   We systematically investigate the production of $J/\psi +\gamma$ in $\gamma \gamma$ collisions within nonrelativistic QCD (NRQCD) factorization, with the direct-photon channel calculated specifically up to the next-to-leading order in ${\alpha }_s$. Calculations for CEPC energy region show the resolved photon contribution is negligible, while the direct photon process dominates, yielding substantial annual $J/\psi$ yields. Significant modifications to $J/\psi$ polarization parameters emerge from color-octet mechanisms, and different NRQCD long distance matrix elements (LDMEs) further yield distinct polarization patterns. Furthermore, the polarization predictions are highly sensitive to the ${}^3{P}_J^{[8]}$ LDME, while being insensitive to the ${}^1{S}_0^{[8]}$ and ${}^3{S}_1^{[8]}$ LDMEs. Leveraging the cleaner environment of $e^{+}{e}^{-}$ collisions versus hadronic processes, the production of $J/\psi$ associated with a photon in $\gamma \gamma$ collisions provides a high-precision platform to test LDMEs universality and resolve longstanding $J/\psi$ polarization puzzles.

   hep-phEPJC(2026)·0 citations
4. 04*

   Unstable Particles in Quantum Field Theory

   Scott Willenbrock🇺🇸

   In honor of Dave Roper's 90th birthday, I present a pedagogical introduction to our modern understanding of unstable particles in Quantum Field Theory, based on the analytic structure of the propagator, with occasional remarks on the Roper resonance. I discuss the mass and decay rate of unstable particles, Breit-Wigner resonance formulae and width, poles and branch cuts, and pole trajectories.

   hep-phhep-exhep-latActa Phys.Polon.B(2026)·1 citation
5. 05*

   Rescaled Leptonic Unitarity Triangles and Rephasing Invariants

   Shu Luo🇨🇳

   The field of neutrino physics has made significant progress in measuring the strength and frequency of neutrino and antineutrino oscillations in the past two decades. It is clear that the amplitudes involved in the neutrino oscillation probabilities are all rephaping invariants of the quartet forms of the elements of the PMNS mixing matrix. We show in this paper how these quartet observables can be directly linked to the rescaled leptonic unitarity triangles within the framework of three active neutrinos. We provide a systematic discussion of the nine CP-conserving quartets ${\mathcal{R}}_{\gamma k}^{}\equiv \mathrm{Re}\left[V_{\alpha i}^{}{V}_{\beta j}^{}{V}_{\alpha j}^{\ast }{V}_{\beta i}^{\ast }\right]$ along with the universal Jarlskog invariant of CP violation $\mathcal{J}\equiv {\sum }_{\gamma }{ϵ}_{\alpha \beta \gamma }^{}{\sum }_k{ϵ}_{ijk}^{}\mathrm{Im}\left[V_{\alpha i}^{}{V}_{\beta j}^{}{V}_{\alpha j}^{\ast }{V}_{\beta i}^{\ast }\right]$, and place particular emphasis on the matter effect on these quartets. In addition to the well-known Naumov relation for the Jarlskog invariant $\mathcal{J}$, similar relations connecting $\mathcal{R}$ in vacuum and its effective counterparts $\tilde{\mathcal{R}}$ in matter are introduced and examined in detail. We find that the effective CP-conserving invariants ${\tilde{\mathcal{R}}}_{\alpha i}^{}$ in matter can be regarded as linear combinations of their vacuum counterparts. With the latest global fit data of neutrino masses and mixing elements, numerical analyses are carried out to give an intuitive understanding of how these rephasing invariants evolve as the matter density increases.

   hep-phNPB(2026)·3 citations
6. 06*

   Charm associated production of the pseudoscalar Higgs boson $h^{\prime \prime }$ in the MCPM' at the LHC

   Rafał Maciuła🇵🇱 · Markos Maniatis🇨🇱 · Otto Nachtmann🇩🇪 · Antoni Szczurek🇵🇱

   We discuss charm associated production of the pseudoscalar Higgs boson $h^{\prime \prime }$ in the MCPM'. In our analysis we assume $m_{h^{\prime \prime }}$ = 95.4 GeV, which corresponds to an enhancement observed by the CMS collaboration in the $\gamma \gamma$ channel. As discussed recently, the MCPM' is consistent with the CMS enhancement. In this model the $h^{\prime \prime }$ Higgs boson of this mass decays dominantly into $c\bar{c}$ jets. The cross section for the associated $h^{\prime \prime }$ production in $pp\to h^{\prime \prime }c\bar{c}$ is found to be almost as big as that for the Drell-Yan (DY) $c\bar{c}\to h^{\prime \prime }$ production, much larger than that for two-gluon fusion $gg\to h^{\prime \prime }$. Since in the MCPM' the dominant $h^{\prime \prime }$ decay is into the $c\bar{c}$ channel we have to deal with the $pp\to c\bar{c}c\bar{c}$ process with $c$ and $\bar{c}$ jets. In addition to the signal processes, we have sizeable single parton scattering (SPS) and double parton scattering (DPS) nonresonant background. In our analysis we include diagrams of gluon-gluon fusion $gg\to h^{\prime \prime }$ which lead to the $c\bar{c}c\bar{c}$ final state. We discuss also the possible role of the reaction $pp\to h^{\prime \prime }{h}^{\prime \prime }$. Assuming 100\% c and $\bar{c}$ jet tagging we discuss in detail how to improve the signal-to-background ratio. Our analysis shows promising resonance-like enhancements and relatively large cross sections in the $c\bar{c}c\bar{c}$ channel within the MCPM'. In an appendix we discuss the total cross section for $h^{\prime \prime }$ production at the LHC. We also compare distributions for the reactions $pp\to h^{\prime \prime }X$ and $pp\to ZX$ with $h^{\prime \prime }$ and $Z$ decaying to $c\bar{c}$ and ${\mu }^{+}{\mu }^{-}$. We hope that the LHC collaborations will in the future perform the experimental studies corresponding to the theoretical studies discussed here.

   hep-phPRD(2026)·0 citations
7. 07*

   Formation of primordial black holes through Q-balls

   Shinta Kasuya🇯🇵 · Masahiro Kawasaki🇯🇵 · Alexander Kusenko🇺🇸 · Shunsuke Neda🇯🇵

   We study the primordial black hole (PBH) formation from Q-balls that are non-topological solitons in scalar field theories. We develop a formula for calculating the density perturbations from the Q-ball charge distribution. We also re-examine the condition for the PBH formation in the matter-dominated era and show that the previously derived formula for super-horizon density fluctuations can be applied to the sub-horizon density perturbations. As an example, we consider the Q-balls in the case of gauge-mediated supersymmetry (SUSY) breaking, whose charge distribution was obtained by the lattice simulation. We find that the density perturbations are large enough to produce a significant number of PBHs with mass $10^{-15}{M}_{\odot }-5\times 10^{-12}{M}_{\odot }$, which can explain all the dark matter in the universe. In the context of supersymmetry, this mass range corresponds to the SUSY breaking scale $\sim 10^6$ GeV, which is consistent with the SUSY particle masses $\sim 10$ TeV.

   hep-phJCAP(2026)·1 citation
8. 08*

   Short-flow-time expansion of non-singlet twist-two operators at next-to-next-to-leading order QCD

   Robert V. Harlander🇩🇪 · Jonas T. Kohnen🇩🇪 · Andrea Shindler🇩🇪

   The gradient-flow formalism provides a framework for the direct determination of moments of parton distribution functions (PDFs) from lattice QCD calculations. Their conversion from the gradient-flow scheme to $\overline{\text{MS}}$ requires the matching coefficients of the short-flow-time expansion, which can be computed perturbatively. We determine these coefficients for the first six non-singlet PDF moments up to next-to-next-to-leading order in the strong coupling.

   hep-phhep-latEPJC(2026)·5 citations
9. 09*

   Investigation of the Spectator Effect on Light Nuclei Production in Nucleus-Nucleus Collisions at High Baryon Density Region

   Hongcan Li🇨🇳 · Li'Ang Zhang🇨🇳 · Junyi Han🇨🇳 · Yaping Wang🇨🇳 · Junlin Wu🇨🇳 · Guannan Xie🇨🇳 · Gao-Chan Yong🇨🇳

   The light nuclei yields and their yield ratios, regarded as sensitive probes of the QCD phase structure, have been extensively measured at various collision energies. However, due to limited detector acceptance, the $p_{\mathrm{T}}$-integrated yield is often obtained by extrapolating from the measured $p_{\mathrm{T}}$ spectrum to the unmeasured low-$p_{\mathrm{T}}$ region using model-based fits. Simulations using AMPT-HC combined with an after-burner coalescence approach indicate a significant enhancement of light nuclei production at low $p_{\mathrm{T}}$, particularly in peripheral collisions and at forward rapidities, driven primarily by spectator nucleons. As a result, standard extrapolation procedures may systematically miss this additional low-$p_{\mathrm{T}}$ component, leading to an underestimate of the $p_{\mathrm{T}}$-integrated light-nucleus yields in such scenarios.

   hep-phPLB(2026)·1 citation
10. 10*

    Cascades of gluons at high energies and their QI measures

    Krzysztof Kutak🇵🇱 · Michał Praszałowicz🇵🇱

    In this contribution we report on recent extension of one dimensional dipole cascade models to account for saturation and transition to vacuum \cite{Kutak:2025syp}. We analyze properties of the models using Quantum Information tools. Furthermore, we present a description of the hadronic entropy measured by LHCb and predictions for the purity measurement. %we provide description of hadronic entropy as measured by LHCb and provide predictions for measurement of purity.

    hep-phPoS(2026)·3 citations
11. 11*

    Parameter Inference from Final-State Entanglement in Higgs Decays

    Jia Liu🇨🇳 · Masanori Tanaka🇨🇳 · Xiao-Ping Wang🇨🇳 · Jing-Jun Zhang🇨🇳 · Zifan Zheng🇨🇳

    The decay out-states of unstable Standard Model (SM) particles provide a unique, well-defined intrinsic quantum-information probe of the SM parameter space. We use Higgs decays as a test case: after tracing out kinematics, we compute entanglement among final-state spins and colors across all decay channels and impose a near-maximal entanglement-entropy criterion. This criterion yields quantitative indications for fundamental parameters. Within the SM, the entanglement entropy exhibits a global maximum close to the observed Higgs mass and the measured $W$ mass, the latter being equivalent to the $SU(2{)}_L$ gauge coupling. In a two-parameter kappa framework, applying the same criterion points to an SM-like balance between vector and fermion couplings, constraining the ratio of the sector-wide rescalings. These results suggest that entanglement extremality can serve as a complementary handle on fundamental parameters.

    hep-phquant-phPRD(2026)·10 citations
12. 12*

    POPxf: An Exchange Format for Polynomial Observable Predictions

    Ilaria Brivio (ed.)🇮🇹 · Ken Mimasu (ed.)🇬🇧 · Peter Stangl (ed.)🇩🇪 · Anke Biekötter🇩🇪 · Ana R. Cueto Gómez🇪🇸 · Charlotte Knight🇬🇧 · Luca Mantani🇪🇸 · Eleonora Rossi🇬🇧 · Alejo N. Rossia🇮🇹 · Aleks Smolkovič🇸🇮

    We introduce the Polynomial Observable Prediction Exchange Format, POPxf, a structured, machine-readable data format for the publication and exchange of semi-analytical theoretical predictions in high energy physics. The format is designed to encode observables that can be expressed in terms of polynomials in model parameters, with particular emphasis on Effective Field Theory applications. All relevant assumptions and metadata are recorded explicitly, and the treatment of uncertainties and correlations is flexible enough to capture parameter-dependent effects. The format aims to improve reproducibility, facilitate global fits and reinterpretations, and streamline the use of theoretical predictions across the particle physics community.

    hep-phhep-ex6 citations
13. 13*

    Geometry-induced azimuthal anisotropy in coherent $J/\psi$ photoproduction

    Ding Yu Shao🇨🇳 · Han-Qing Yu🇨🇳 · Cheng Zhang🇨🇳 · Jian Zhou🇨🇳

    Azimuthal anisotropies in heavy-ion collisions are conventionally interpreted as signatures of hydrodynamic flow. We demonstrate that in peripheral collisions, a significant $\cos 2\varphi$ asymmetry in the decay leptons of coherently photoproduced $J/\psi$ mesons arises purely from the initial-state geometry of the nuclear electromagnetic field. This modulation originates from the linear polarization of coherent photons, which is radially aligned in impact parameter space and transferred to the vector meson. By employing light-cone perturbation theory within the dipole formalism, we calculate the centrality dependence of this asymmetry for collisions at RHIC and LHC energies. Our predictions quantitatively reproduce STAR data. This observable thus provides a rigorous benchmark for distinguishing electromagnetic initial-state effects from collective medium dynamics.

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

    Reciprocity in Heavy Quark Fragmentation Function

    V.V.Kiselev🇷🇺

    At high energies a form of fragmentation function for a heavy quark into a hadron is substantiated to agree with a reciprocity relation to the distribution of heavy quark as the virtual parton in the hadron. The relevance of the relation is analysed in its application to empirical data.

    hep-ph1 citation
15. 15*

    A simple introduction to soft resummation

    Stefano Forte🇮🇹 · Giovanni Ridolfi🇮🇹

    We provide an elementary pedagogical introduction to some basic concepts and techniques of soft (or Sudakov) resummation, specifically in QCD, paying particular attention to simple but useful tricks of the trade. We briefly review collinear (Altarelli-Parisi) and infrared (eikonal)factorization, cancellation of infrared singularities and factorization of mass singularities. We recall basic concepts on renormalization group invariance and the solution of renormalization group equations. We then show how threshold resummation can be derived from a renormalization group argument following from the cancellation of infrared singularities. We discuss various equivalent forms of the resummed result, and we briefly present transverse momentum resummation.

    hep-phActa Phys.Polon.B(2026)·1 citation
16. 16*

    ${\mathbb{Z}}_2$-Stable Dark Matter via Broken $\text{SU}(5)$ Gauge Bosons

    E. J. Thompson🇨🇦

    I construct and analyze a dark matter sector that is neutral under the unbroken Standard Model gauge group and couples only to the broken $\text{SU}(5)$ gauge directions, the leptoquark vectors $X,Y$. An exact ${\mathbb{Z}}_2$ renders the dark matter stable. I give a gauge-covariant definition of projectors onto the unbroken Standard Model and broken ($X,Y$) subspaces, demonstrate that the covariant derivative of dark matter selects only $X,Y$, and integrate out $X,Y$ at tree level to obtain the leading effective operators. I also derive the loop-induced ${\chi }^2{G}_{\mu \nu }^a{G}^{a\mu \nu }$ coupling to gluons, prove color neutrality, and show consistency with cold dark matter phenomenology. Cosmological production proceeds via UV freeze-in or even more suppressed channels in.

    hep-phastro-ph.COgr-qchep-th3 citations
17. 17*

    In-depth analysis of the clustering of dark matter particles around primordial black holes. Part II. Analytical prescriptions for spikes

    Julien Lavalle🇫🇷 · Pierre Salati🇫🇷

    Primordial black holes (PBHs) are very appealing dark matter (DM) candidates. It is highly plausible though, should they exist, that they would not make up all of the DM. Several studies showed that if the rest of DM is made of thermal particles, then these should accumulate around such PBHs, leading to the formation of very dense spikes in the radiation era. We contributed a detailed analytical study about this phenomenon, providing clear explanations as for the origin of scaling relations in the form of power-law density profiles with up to 3 different spectral indices, i.e. $3/4$, $3/2$, and $9/4$, and 4 asymptotic regimes. Here, we further derive an approximate analytical solution that enables fast numerical predictions for the density profiles of these spikes. We also address the specific case of self-annihilating DM species and derive new approximate analytical formulae. Our approximate density yields the correct annihilation rate within $\pm 15\%$ precision. We then focus on indirect detection in the cosmic microwave background and in extragalactic gamma-rays. We shed new and subtle light on how mutually exclusive PBHs and self-annihilating DM species can really be. In particular, the discovery of a population of sub-solar PBHs would set stringent constraints on the $s$-wave annihilation cross-section of these particles, a point so far missed in the literature.

    ↳ astro-ph.HEastro-ph.COhep-phJCAP(2026)·3 citations
18. 18*

    GSpyNetTreeS: a machine learning solution for glitch localization in time and frequency

    Man Leong Chan🇨🇳 · Jess McIver🇺🇸 · Yannick Lecoeuche🇺🇸 · Dhatri Raghunathan🇺🇸 · Sofía Álvarez-López🇺🇸 · Julian Ding🇺🇸 · Annudesh Liyanage🇺🇸 · Raymond Ng🇺🇸 · Heather Fong🇺🇸

    Data from ground-based gravitational wave detectors are often contaminated by non-Gaussian instrumental artifacts or detector noise transients. Unbiased source property estimation relies on the ability to correctly identify and characterize these artifacts and remove them if necessary. To this end, the LIGO-Virgo-KAGRA Collaboration has implemented candidate vetting for all significant candidates to identify the presence of artifacts and assess the need for mitigation. The current candidate vetting process requires human experts to identify the frequency ranges and the time windows associated with any data quality issues present. Differences in judgment between human experts may cause inconsistency, making results difficult to reproduce across gravitational wave events. We present GSpyNetTreeS, an extension to GSpyNetTree based on the You Only Look Once algorithm, for the automatic detection, classification, and time-frequency localization of detector noise transients. As a proof of concept, we tested GSpyNetTreeS's performance on the data collected by the LIGO detectors during the third observing run for gravitational waves as well as common detector glitch classes included in GSpyNetTree: Blip, Low frequency blip, Low frequency line and Scratchy. We also demonstrated that GSpyNetTreeS is capable of accurately identifying common glitch classes and capturing the frequency and time information associated with detected detector noise transients, establishing its potential as an automatic event validation tool for LIGO-Virgo-KAGRA's observing runs.

    ↳ astro-ph.IMgr-qchep-ph2 citations
19. 19*

    Self-bound quark stars with a first-order two-to-three flavor phase transition

    G. Teruya🇧🇷 · G. Lugones🇧🇷 · A. G. Grunfeld🇦🇷

    We investigate self-bound quark stars in a flavor-dependent quark-mass density-dependent model with an excluded-volume correction. We chart the parameter space at zero pressure to identify self-bound regimes, including parametrizations in which self-bound two-flavor matter undergoes a genuine first-order $ud\to uds$ transition at finite pressure. We construct cold, $\beta$-equilibrated stellar sequences and compute the corresponding global properties (mass-radius relation, tidal deformability, and moment of inertia). For a wide region of the model parameter space, we find that the onset of a $uds$ core occurs before the maximum-mass configuration is reached, yielding self-bound hybrid stars that follow the typical strange-quark-star sequence morphology but develop a characteristic kink at $p_c=p_{\mathrm{tr}}$ along the stellar curves. The excluded-volume parameter $\kappa$ controls the stiffness of the equation of state and thus masses, radii, tidal deformabilities, and moments of inertia; intermediate repulsion typically reconciles $M_{\max }\gtrsim 2M_{\odot }$ with current astrophysical constraints. We further identify two equation-of-state-insensitive trends: dimensionless moment of inertia versus compactness and gravitational versus baryonic compactness. These results provide model-guided priors and tools for discriminating between hadronic and self-bound equations of state with multimessenger data.

    ↳ astro-ph.HEastro-ph.SRhep-phnucl-thPRD(2026)·1 citation
20. 20*

    Dark Matter Admixed White Dwarfs: A Single-Fluid Approach

    Rajasmita Sahoo🇮🇳 · Somnath Mukhopadhyay🇮🇳 · Mrutunjaya Bhuyan🇮🇳

    In this study, we investigate the influence of an admixed fermionic dark matter (DM) component on the equilibrium structure of white dwarfs (WDs), with particular emphasis on the effects of varying the DM particle mass ($m_{\mathrm{DM}}$) and DM fraction ($f_{\mathrm{DM}}$). Notably, we employ a single-fluid approximation for the first time in this context, wherein the baryonic and DM contributions to the total energy density and pressure are treated within a unified framework, assuming non-interacting fermionic DM in hydrostatic equilibrium with baryons. We examine how variations in $m_{\mathrm{DM}}$ and $f_{\mathrm{DM}}$ modify the equation of state (EoS), the mass-radius relationship, and the internal mass and pressure distributions of WDs. Our results show that the presence of DM softens the EoS, with lighter DM particles providing stronger pressure support and leading to more extended stellar structures. Increasing the DM mass fraction leads to a more compact configuration, reducing both the radius and maximum mass of the WD. We further demonstrate that heavier DM particles enhance stellar compactness and can eventually drive the star toward gravitational instability. Moreover, the analysis of mass-radius relationships reveals that while small fractions of DM are consistent with observed WD masses, the radii predicted by our models are smaller than observations, suggesting additional influences such as rotation or magnetic fields. Our stability analysis confirms that the inclusion of dark matter does not lead to instability within the expected parameter space, indicating that white dwarfs admixed with dark matter can remain dynamically stable under certain conditions. These findings show that even a small admixture of DM can modify the structural properties and stability limits of WDs, providing a potential indirect astrophysical probe of DM particle properties.

    ↳ astro-ph.SRastro-ph.HEhep-phPRD(2026)·2 citations
21. 21*

    Covariance spectrum of MAXI J1820+070: On the nature of the Comptonizing flow

    Shuai-Kang Yang🇨🇳 · Bei You🇨🇳 · Niek Bollemeijer🇳🇱 · Phil Uttley🇳🇱 · A. J. Tetarenko🇨🇦 · Andrzej A. Zdziarski🇵🇱 · Liang Chen🇨🇳 · P. Casella🇮🇹 · J. A. Paice🇬🇧 · Yang Bai🇨🇳 · Sai-En Xu🇨🇳

    We present an analysis of the covariance spectrum of the black hole X-ray binary MAXI J1820+070 during its hard state. For the first time, we extend coherence and covariance studies into the hard X-ray band up to 150 keV. We detect a clear drop in coherence above 30 keV on both short- and long-timescales relative to the 2-10 keV reference band. To investigate the origin of the coherent variability, we simultaneously fit the short- and long-timescale covariances and the time-averaged spectra with a Comptonization model. Surprisingly, the electron temperature associated with long-timescale variability is significantly higher than that on short timescales. Moreover, the temperature on long timescales remains relatively constant throughout the hard state, whereas the short-timescale temperature evolves with X-ray luminosity. We attribute the drop in coherence to multiple sources of seed photons, i.e., the blackbody and synchrotron photons. The independence between these two photon fields leads to the drop in coherence. To explain the lower electron temperature on short timescales, we propose a two-Comptonization framework in which short-timescale variability arises from a vertically extended central region, while long-timescale variability originates at larger radii. The elevated geometry of the inner region leads to illumination primarily by cooler outer-disk photons, yielding a lower electron temperature. In this case, the evolution of the height of the elevated region could explain the evolution of the electron temperature associated with the coherent variability throughout the hard state.

    ↳ astro-ph.HEhep-phApJ(2026)·2 citations
22. 22*

    Effect of the Memory Burden on Primordial Black Hole Hot Spots

    Nathaniel Levy🇬🇧 · Lucien Heurtier🇬🇧

    When primordial black holes (PBHs) evaporate, they deposit energy in the surrounding plasma, leading to temperature gradients, or hot spots, that evolve during the evaporation process. Motivated by recent studies suggesting that a memory burden may slow down PBH evaporation, we explore how a suppression of the evaporation rate affects the morphology of such hot spots. We include such a suppression in the form of transfer functions and derive general formulas for the hot-spot core temperature and radius. Applying our results to illustrative scenarios, we find that in the vanilla memory burden scenario in which the evaporation rate and Hawking temperature are exactly constant, the hot-spot temperature is substantially lowered. Nonetheless, we show that alternative scenarios may lead to sizeable hot spots with morphologies that differ significantly from the semi-classical case.

    ↳ astro-ph.COhep-phPRD(2026)·6 citations
23. 23*

    Subtleties of non-Abelian D-brane actions and their effect on holographic heavy-light meson spectra

    Carlos Hoyos🇪🇸 · Niko Jokela🇫🇮 · Andrea Olzi🇮🇹

    We revisit the holographic description of heavy light mesons in the D3-D7 system at zero temperature, analyzing the dynamics of the coupled probe D7 branes through the non-Abelian Dirac-Born-Infeld action. Distinct quark masses are realized by separating the flavor branes, producing holographic flavor hierarchies. We refine the calculation made in previous works: we impose Hermiticity on the induced metric and fix the expansion of the determinant for matrix valued fields. Implementing these improvements yields modified fluctuation equations and quantitatively different meson spectra: the scalar modes become heavier while the vector modes become lighter, removing the degeneracy reported in the literature. At finite 't Hooft coupling, we also observe a qualitatively different dependence of the vector modes on the quark masses. The resulting prescription provides a consistent, broadly applicable framework for incorporating non-Abelian flavor dynamics into holographic models and can be readily extended to situations away from the vacuum.

    ↳ hep-thhep-phJHEP(2026)·1 citation
24. 24*

    How Significant are Cosmological Collider Signals in the Planck Data?

    Petar Suman🇬🇧 · Dong-Gang Wang🇬🇧 · Wuhyun Sohn🇫🇷 · James R. Fergusson🇬🇧 · E. P. S. Shellard🇬🇧

    The search for primordial non-Gaussianities (PNG) is theoretically well motivated but remains observationally challenging. Tight constraints with low significance for the standard non-Gaussian shapes suggest that detection may lie beyond the reach of near-future experiments. However, tests of PNG are highly template-dependent. From a theory perspective, a whole new family of bispectrum shapes arise in the cosmological collider program, with distinct signatures of heavy particles during inflation. In this work, we provide a class of simplified collider templates for these particles that encompasses a broader range of masses, sound speeds, and interactions. We propose that, given the current state of observations, the most effective strategy to search for PNG signals is through orthogonalizing the collider templates, such that they are uncorrelated with the tightly constrained single field predictions. Using the Modal pipeline and Planck CMB data, we perform a systematic parameter scan of the collider templates with the most significant result reaching $2.4\sigma$ for spin-0, after taking into account the look-elsewhere effect; indicative results for spin-1 and spin-2 peak near 2$\sigma$. These results indicate that, with refined collider templates and improved data analysis strategies, there are credible prospects with forthcoming observations to detect PNG and also rule out single field inflation.

    ↳ astro-ph.COgr-qchep-phhep-th18 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.