Tue·Dec 30, 2025Tuesday·December 30, 2025

1. 01*

   Can high-$p_{\perp }$ theory and data constrain $\eta /s$?

   Bithika Karmakar🇵🇱 · Dusan Zigic🇷🇸 · Igor Salom🇷🇸 · Jussi Auvinen🇫🇮 · Pasi Huovinen🇵🇱 · Marko Djordjevic🇷🇸 · Magdalena Djordjevic🇷🇸

   Understanding the temperature dependence of the specific shear viscosity $(\eta /s)$ is crucial for characterizing the properties of the QCD matter produced in ultrarelativistic heavy-ion collisions. Since, low-$p_{\perp }$ theory and data are only weakly sensitive to the typical forms of $\eta /s(T)$, especially at high temperatures, we use high-$p_{\perp }$ data and theory to impose additional constraints on it. Our approach, based on dynamical radiative and collisional energy loss of high-$p_{\perp }$ particles, provides promising results in constraining the temperature dependence of $\eta /s$.

   hep-phJ.Subatomic Part.Cosmol.(2025)·0 citations
2. 02*

   Orbital angular momentum in the pion and kaon: rest-frame and light-front

   Y.-Y. Xiao🇨🇳 · Z.-N. Xu🇪🇸 · Z.-Q. Yao🇩🇪 · C. D. Roberts🇨🇳 · J. Rodríguez-Quintero🇪🇸

   Orbital angular momentum (OAM) is not a Poincaré invariant quantity; so, its value is observer dependent. Notwithstanding that, in quantum chromodynamics, a Poincaré-invariant theory, OAM is part of every hadron wave function. Using continuum Schwinger function methods, we elucidate both the subjective character of in-hadron OAM and expose some of its impacts on pion and kaon structure and observables. For instance, working with light-front projections of their Bethe-Salpeter wave functions, it is found that the pion is a roughly 50/50 mix of light-front OAM zero and one components and the kaon is a 60/40 system. The overall picture is that (near) Nambu-Goldstone modes are complex bound states, each with significant intrinsic OAM, independent of the observer's reference frame. This feature must be accounted for in the calculation of observables. Inductively, the same is true for all hadrons.

   hep-phhep-exhep-latnucl-ex+1PLB(2026)·5 citations
3. 03*

   Nonequilibrium QCD in heavy-ion collisions: Kinetic theory and jet modifications during the initial stages

   Florian Lindenbauer🇦🇹

   This thesis focuses on how jets are modified by the nonequilibrium quark-gluon plasma during the initial stages in heavy-ion collisions. Its influence on their propagation is typically encoded in a single medium function, the dipole cross section. Its small distance behavior is characterized by the jet quenching parameter $\hat{q}$, and we obtain its numerical value throughout the pre-equilibrium stage, finding values comparable in magnitude to the earlier Glasma stage. We also compute the more general elastic collision kernel, obtained by Fourier transforming the dipole cross section. This constitutes an important step to facilitate the understanding of jet-medium interactions during the initial stages in heavy-ion collisions. Additionally, we improve QCD kinetic theory simulations by employing a more realistic (HTL) screening mechanism to incorporate medium effects, which we compare with simpler screening mechanisms. An expanding plasma realized in the initial stages of heavy-ion collisions exhibits a significantly reduced maximum anisotropy and reduced specific shear viscosity $\eta /s$ when using the improved screening prescription. Moreover, we investigate the gluon splitting rates, which are typically obtained using an isotropic model for the collision kernel. Going beyond that approximation, we find that the splitting rates obtained from the nonequilibrium anisotropic kernel differ significantly both in magnitude and in their qualitative time evolution. We further identify a novel type of weak-coupling attractor, which can be observed in the ratio of the jet quenching parameter and pressure ratio, and is obtained by extrapolating to vanishing coupling. This improved kinetic theory description and novel limiting attractors contribute towards a more realistic modeling of the nonequilibrium QCD plasma and its equilibration and hydrodynamization process during the initial stages.

   hep-phnucl-th0 citations
4. 04*

   Unveiling Primordial Black Hole Relics Through Induced Gravitational Waves

   Misao Sasaki🇯🇵 · Jianing Wang🇯🇵

   Black hole relics are of significant interest in cosmology and theoretical physics. In this work, we consider tiny primordial black holes (PBHs) ( $M_{\text{PBH }}\lesssim 10^7\mathrm{g}$ ) which are generated soon after the end of inflation and evaporate and reheat the Universe before big bang nucleosynthesis (BBN), but leave their remnants due to incomplete evaporation. These PBHs remnants may contribute as part or all of the dark matter (DM) today. Assuming that there exist PBH relics, we point out that the number density of PBH today can be directly read from the peak positions of the induced gravitational waves due to the inhomogeneous PBH distribution. If PBH relics are of Planck mass and they forms all the DM today, the PBH number density would be of $10^{-25}{\mathrm{cm}}^{-3}$ with the peak frequency 60 Hz . The peak frequency scales as $f_{\text{relic }}^{1/3}$ where $f_{\text{relic }}$ is the fraction of the PBH relics in the total DM density. The peak amplitude carries the information of initial PBH abundance. For monochromatic-mass PBH with the current number density $10^{-41}\sim 10^{-25}{\mathrm{cm}}^{-3}$ and initial abundance $10^{-13}\sim 10^{-7}$, the amplitude may be large enough to be detected by planned gravitational wave experiments in the near future.

   hep-phPRD(2026)·8 citations
5. 05*

   Quark Coalescence: Formation of Mesons Including Excited States

   R. J. Fries🇺🇸 · P. Virupapuram · J. Purcell🇺🇸 · H. Anconetani · W. Lippincott🇺🇸 · S. Robicheaux · M. Kordell🇺🇸 · C. M. Ko🇺🇸

   We discuss the quantum mechanics of coalescence of quark-antiquark pairs into mesons using a non-relativistic quark model. We derive the coalescence probabilities assuming a harmonic oscillator potential and generic Gaussian wave packet shapes for the initial quarks and antiquarks. Our particular emphasis is on modeling excited states of the meson spectrum consistently. We provide the formalism to systematically include excited states from the Particle Data Book, and many more predicted by the quark model, up to $L=4$ and masses of about 2.2 GeV for light flavors. We provide estimates of masses and decay branching ratios for unconfirmed states. We use a phase space picture which is appropriate for the quasi-classical nature of the information typically available for the quarks and antiquarks in applications like Monte Carlo simulations. We demonstrate that for typical parton configurations expected in jets, excited meson states are populated abundantly.

   hep-phnucl-exnucl-th1 citation
6. 06*

   Probing the pair production of first-generation vector-like leptons at future $e^{+}{e}^{-}$ colliders

   Yao-Bei Liu🇨🇳 · Stefano Moretti🇬🇧

   This work explores the discovery potential of the first-generation weak isosinglet Vector-Like Leptons (VLLs), denoted by $E^{\pm }$, via pair production at future electron-positron colliders. Our analysis adopts a comprehensive framework that incorporates beam polarization configurations and leverages detailed detector simulations. We focus on two distinct multilepton signatures: the $2\ell +2j+\text{slashed}{E}_T$ and $3\ell +2j+\text{slashed}{E}_T$ final states ($\ell =e,\mu$). Both signatures arise from the decay $E^{\pm }\to Z{e}^{\pm }/W^{\pm }{\nu }_{\ell }$ and are distinguished by the decay patterns of the associated gauge bosons. By applying optimized selection criteria to both signal and background events, we establish exclusion sensitivities and discovery prospects across the VLL mass spectrum. Our findings demonstrate that, for integrated luminosities of $\text{SI}25f{b}^{-1}$, $\text{SI}90f{b}^{-1}$ and $\text{SI}1000f{b}^{-1}$ at corresponding center-of-mass (c.m.) energies of $\text{SI}1TeV$, $\text{SI}1.5TeV$ and $\text{SI}3TeV$, the accessible mass range extends to approximately $\text{SI}490GeV$, $\text{SI}740GeV$ and $\text{SI}1440GeV$, which represents a substantially improvement over the detection limits of existing hadron collider experiments.

   hep-phPRD(2026)·4 citations
7. 07*

   Radiative symmetry breaking in a gauged Zee-Babu model and its gravitational wave imprints

   Indra Kumar Banerjee🇮🇳 · Nabarun Chakrabarty🇮🇳 · Ujjal Kumar Dey🇮🇳

   We construct a classically scale invariant version of the Zee-Babu model governed by an $U(1{)}_{B-L}$ gauge symmetry wherein three right handed neutrinos with identical gauge charges are present. A ${\mathbb{Z}}_2$ symmetry is additionally imposed such that the lightest right handed neutrino becomes a dark matter candidate. A spontaneous breakdown of the $U(1{)}_{B-L}$ gauge group is triggered radiatively through renormalisation group effects and the dimensionful parameters thus emerging are proportional to the corresponding breaking scale $v_{BL}$. We demonstrate in this study how the same $v_{BL}$ controls the dynamics of neutrino mass generation, lepton flavour violation and dark matter phenomenology. It is revealed that the scenario can simultaneously accommodate the observed neutrino masses and mixings, an appropriately low lepton flavour violation and the observed dark matter relic density for 10 TeV $\lesssim v_{BL}\lesssim$ 55 TeV. In addition, the very radiative nature of the set-up signals a strong first order phase transition in the presence of a non-zero temperature. Stochastic gravitational waves stemming from this phase transition are within the reach of detectors such as LISA and BBO. The scenario therefore emerges as a concrete platform to test classical scale invariance that is tied to neutrino masses and dark matter, through gravitational waves.

   hep-ph0 citations
8. 08*

   The $B^{+(0)}\to {\bar{D}}^{0(-)}{D}_{s0}^{\ast }(2317{)}^{+}$ decays and the molecular structure of $D_{s0}^{\ast }(2317)$

   Wei-Hong Liang🇨🇳 · Zhuo-Ran Hu🇨🇳 · Eulogio Oset🇪🇸

   We have conducted a study of the $B^{+(0)}\to {\bar{D}}^{0(-)}{D}_{s0}^{\ast }(2317{)}^{+}$ reactions from the perspective that the $D_{s0}^{\ast }(2317)$ resonance is a molecular state of the $DK$ and $D_s\eta$ components. We have followed a method to evaluate the branching fractions obtaining information from the experimental data on the $B^{+}\to {\bar{D}}^0{K}^{+}{D}^0$, $B^{+}\to {\bar{D}}^0{K}^0{D}^{+}$, $B^0\to D^{-}{K}^{+}{D}^0$, $B^0\to D^{-}{K}^0{D}^{+}$ reactions, which have the $D^0{K}^{+}$ and $D^{+}{K}^0$ pairs in the final state. The approach concentrates the dynamics of the weak process in the branching ratios of these reactions and pays attention to the propagation of the $DK$ components and their strong interaction to form the $D_{s0}^{\ast }(2317)$ resonance. By means of two free parameters, we are able to describe these six rates, showing consistency with the molecular picture of the $D_{s0}^{\ast }(2317)$ state.

   hep-phEPJA(2026)·2 citations
9. 09*

   Stringent constraints on non-standard neutrino interactions using high-purity ${\nu }_{\mu }$ CC events in IceCube DeepCore

   J Krishnamoorthi🇮🇳 · Anil Kumar🇮🇳 · Sanjib Kumar Agarwalla🇮🇳

   The neutral-current (NC) non-standard interactions (NSI) of neutrinos with fermions can modify the flavor oscillations of atmospheric neutrinos as they propagate through the Earth. We present constraints on the NC-NSI parameters ${\epsilon }_{\mu \tau }$ and ${\epsilon }_{\tau \tau }-{\epsilon }_{\mu \mu }$ (one at a time) using a high-purity sample of ${\nu }_{\mu }$ charged-current (CC) atmospheric neutrino events collected by IceCube DeepCore over 7.5 years of livetime. These two parameters significantly affect the ${\nu }_{\mu }$ disappearance channel for which this golden event sample is optimized by the IceCube Collaboration. The best fit to this dataset is consistent with no NSI hypothesis, and we place the most stringent constraints to date: $-0.0094<{\epsilon }_{\mu \tau }<0.0079$ and $-0.030<{\epsilon }_{\tau \tau }-{\epsilon }_{\mu \mu }<0.029$ at 90% confidence level.

   hep-phhep-exphysics.ins-det2 citations
10. 10*

    DGLAP evolution at N${}^3$LO with the $\text{Candia}$ algorithm

    Casey Hampson🇺🇸 · Marco Guzzi🇺🇸

    We present a generalization of the $x$-space $\text{Candia}$ algorithm to next-to-next-to-next-to-leading order (N${}^3$LO) accuracy in Quantum Chromodynamics (QCD) for solving the DGLAP evolution equations for unpolarized parton densities in the nucleon. The algorithm is based on logarithmic expansions of the solution and can be extended to all orders in QCD. An expansion equivalent to the exact solution of the DGLAP equation at N${}^3$LO is presented in the non-singlet sector. Results for approximate N${}^3$LO PDFs, evolved using the most recent approximations to the N${}^3$LO DGLAP splitting functions, are provided for benchmarking. The new version of the code, $\text{Candia-v2}$, is publicly available at https://github.com/champso1/candia-v2.

    hep-phPRD(2026)·5 citations
11. 11*

    Heavy dark matter in rapidly evolving massive stars

    Sandra Robles🇺🇸 · Walter Tangarife🇺🇸 · Giorgio Busoni🇦🇺

    We study the impact of heavy dark matter (DM) captured in massive stars via scattering(s) with the star constituents. We focus on the first stars and use stellar evolution simulations to track down how DM capture evolves over time from the zero-age main sequence to the late metal-rich stages of stellar evolution. During the early hydrogen-helium-dominated phase, the capture process is well described by scattering with two targets. As a star evolves, metal production leads to the formation of a dense core surrounded by a lighter envelope. The core significantly enhances the capture of ultra-heavy DM; in this case, three distinct nuclear species are required to accurately describe multiple-scattering capture. We use the Eddington inversion method to obtain a realistic DM velocity distribution, better suited when the star is near the center of a halo, than the widely used Maxwell-Boltzmann distribution. We find that heavy DM would be able to thermalize and achieve capture-annihilation equilibrium within a massive star's lifetime for regions of the parameter space not excluded by direct detection. For non-annihilating DM, because of the high amount of targets available for capture and despite massive stars being short-lived, it would even be possible for DM to achieve self-gravitation and collapse to a black hole, which eventually could swallow the star from within before the expected end of the star's life, for non-excluded regions of the parameter space. Our results highlight the dependence of DM capture on the stellar evolutionary stage, composition, and halo location, demonstrating that accurate modeling of massive stars is essential for constraining heavy DM with primordial stellar populations.

    hep-phastro-ph.COastro-ph.GAastro-ph.SRJCAP(2026)·0 citations
12. 12*

    Lepton Number Violation at the LHC in Radiative Neutrino Mass Models with Leptoquarks

    K.S. Babu🇺🇸 · Rahool Kumar Barman🇯🇵 · Dorival Gonçalves🇺🇸

    We investigate the prospects for observing lepton number violation (LNV) by two units, $|\Delta L|=2$, at the LHC within the leptoquark variant of the Zee Model, where Majorana neutrino masses arise radiatively at one-loop. The model features an $SU(2{)}_L$ doublet and singlet leptoquarks, whose interactions produce a distinctive same-sign dilepton plus jets signature, $pp\to {\ell }^{\pm }{\ell }^{\prime \pm }+\text{jets}$. Taking into account current experimental constraints, we identify the dominant production channels for this LNV signal and perform a detailed collider analysis. We find that the HL-LHC can probe leptoquark masses up to $m_{\mathrm{LQ}}\sim 1.5\mathrm{TeV}$ with this process. Observation of this signal would provide a direct test of LNV and would unambiguously establish the Majorana nature of neutrinos.

    hep-phhep-ex0 citations
13. 13*

    Toward the Effective Light and Heavy QCD Axion Scenarios

    Hai-Jun Li🇨🇳

    In this work, we investigate the effective parameter space associated with the axion mass and the axion decay constant in both the light and heavy QCD axion scenarios. We initiate our discussion by considering the simplest case of two axions, quantitatively analyzing the parameter space in these two distinct scenarios. We find that the axion mass ratios exhibit a high degree of similarity in these two situations. In contrast, the ratios of axion decay constants display a complete opposition. Furthermore, we generalize our conclusions to encompass the case of multiple axions.

    hep-phastro-ph.CO0 citations
14. 14*

    Bell nonlocality and entanglement in ${\chi }_{cJ}$ decays into baryon pair

    PengCheng Hong🇨🇳 · RongGang Ping🇨🇳 · WeiMin Song🇨🇳

    We present a systematic analysis of Bell nonlocality and entanglement in ${\chi }_{cJ}$($J=0,1,2$) decays into baryon pair($B\bar{B}$), with particular emphasis on their production via the process $e^{+}{e}^{-}\to \psi (2S)\to \gamma {\chi }_{cJ}$ at BESIII. From the baryon-antibaryon spin density matrix, we construct measurable Bell observables and concurrence, revealing a striking hierarchy of quantum correlations: ${\chi }_{c0}$ decays exhibit maximal violation and entanglement; ${\chi }_{c1}$ decays violate Bell inequalities for ${\theta }_1\in (0,\pi )$ with angle-modulated strength; we find that the $B\bar{B}$ pair in ${\chi }_{c2}$ decays is in a separable state, and no indication of Bell inequality violation is observed. We provide complete analytical results for $J=0,1$ and quantitative, uncertainty-aware estimations for $J=2$ based on experimental inputs from BESIII. These results establish the ${\chi }_{cJ}$ system produced via this radiative transition as a novel and promising platform for testing quantum entanglement and Bell nonlocality in high-energy collisions.

    hep-phhep-exquant-phPRD(2026)·8 citations
15. 15*

    Probing Lorentz Invariance Violation at High-Energy Colliders via Intermediate Massive Boson Mass Measurements: Z Boson Example

    Z. Kepuladze · J. Jejelava

    Lorentz invariance (LI) is a foundational principle of modern physics, yet its possible violation (LIV) remains an intriguing window to physics beyond the Standard Model. While stringent constraints exist in the electromagnetic and hadronic sectors, the weak sector-particularly unstable bosons-remains largely unexplored. In this work, based on our recent studies and conference presentation, we analyze how LIV manifests in high-energy collider experiments, focusing on modifications of Z boson dispersion relations and their impact on resonance measurements in Drell--Yan processes. We argue that precision measurements of resonance masses at colliders provide sensitivity to LIV at the level of $10^{-9}$, comparable to bounds derived from cosmic rays. We also discuss the interplay between LIV and gauge invariance, highlighting why only specific operators provide physical effects. The phenomenological implications for both Z and W bosons are outlined, with emphasis on experimental strategies for current and future colliders.

    hep-phhep-ex
16. 16*

    Low-energy $e^{+}{e}^{-}\to \gamma \gamma$ at NNLO in QED

    Tim Engel🇩🇪 · Marco Rocco🇮🇹 · Adrian Signer🇨🇭 · Yannick Ulrich🇬🇧

    We present a fully differential computation of $e^{+}{e}^{-}\to \gamma \gamma$ at next-to-next-to-leading order in QED. The process has been implemented into McMule, completing its set of next-to-next-to-leading-order calculations for the most important $2\to 2$ processes. The results allow for generic applications to electron-positron colliders with centre-of-mass energies up to a few GeV, particularly for luminosity measurements.

    hep-phhep-exPLB(2026)·1 citation
17. 17*

    TauSpinner algorithms for including spin and New Physics effects in $\bar{q}q\to Z/{\gamma }^{\ast }\to \tau \tau$ process

    A.Yu. Korchin🇺🇦 · E. Richter-Was🇵🇱 · Z. Was🇵🇱

    The possible anomalous New Physics contributions to dipole and weak dipole moments of the $\tau$ lepton bring renewed interest in development and revisiting charge-parity violating signatures in $\tau$-pair production in $Z$-boson decay at energies of the LHC. In this paper, we discuss effects of anomalous contributions to polarisation and spin correlations in the $\bar{q}q\to {\tau }^{+}{\tau }^{-}$ production processes, with $\tau$ decays included. Because of the complex nature of the resulting distributions, Monte Carlo techniques are useful, in particular of event reweighing with studied New Physics phenomena. Extensions of the Standard Model spin amplitudes, within Improved Born Approximation used for matrix element, are implemented in the TauSpinner program. This is mainly with $\tau$ dipole and weak dipole moments in mind, but is applicable to arbitrary New Physics interactions, provided they can be encapsulated into the Standard Model $2\to 2$ structure of matrix element extensions. Implementation allows one also to introduce arbitrary phase-shift between vector and axial-vector couplings of $Z$ boson to $\tau$ leptons, which would have impact on observed transverse spin correlations. Basic formulas and algorithm principles are presented, together with distributions for spin correlation matrix. Numerical examples of impact on experimental signatures are shown in case of ${\tau }^{\pm }\to {\rho }^{\pm }{\nu }_{\tau }\to {\pi }^{\pm }{\pi }^0{\nu }_{\tau }$ decays. Information on how to use and configure the TauSpinner program is given in Appendix.

    hep-phActa Phys.Polon.B(2026)·1 citation
18. 18*

    Mini-review on the production of Primordial Black Holes from First-Order Phase Transitions in the Early Universe

    Indra Kumar Banerjee🇮🇳 · Ujjal Kumar Dey🇮🇳 · Shaaban Khalil🇪🇬

    We review the creation mechanism of primordial black holes from first order phase transitions. We discuss various model-dependent and independent mechanisms and relate the properties of these mechanisms to the properties of primordial black holes. For each of these mechanisms, we provide model-specific examples.

    hep-phastro-ph.COgr-qc2 citations
19. 19*

    $\mathcal{O}({\alpha }_s^2\alpha )$ corrections to quark form factor

    Tanmoy Pati🇮🇳 · Narayan Rana🇮🇳 · V. Ravindran🇮🇳

    We present the analytic results for the non-singlet contributions to the three-loop mixed strong-electroweak $\mathcal{O}({\alpha }_s^2\alpha )$ virtual corrections to the quark form factors. The primary challenge of this computation arises from the presence of massive vector bosons within the loops. This significantly increases the complexity of the integration-by-parts reduction of the scalar integrals and complicates their evaluation via the method of differential equations. To obtain the physical results, we perform the appropriate ultraviolet renormalization and subtract the universal infrared divergences. The resulting finite remainders are expressed in terms of Harmonic Polylogarithms and Generalized Polylogarithms.

    hep-phhep-exhep-thJHEP(2026)·2 citations
20. 20*

    Total decay rate of a muon bound to a light nucleus

    Andrzej Czarnecki🇨🇦 · A. O. Davydov🇨🇦 · M. Y. Kaygorodov🇨🇳

    We revisit the total decay rate of a muon being in the ground state of a Coulomb potential with atomic charge numbers $4\le Z\le 9$. The discrepancy between the perturbative $(\alpha Z{)}^2$ result of [Phys. Rev. \textbf{119}, 365 (1960)] and the fully relativistic partial-wave calculation of [At. Data Nucl. Data Tables \textbf{54}, 165 (1993)] for oxygen ($Z=8$) is shown to originate from insufficient convergence of the partial-wave series in the latter work. Our accurate relativistic calculations restore agreement with the perturbative $\alpha Z$~expansion and indicate a negative sign for the next-order $(\alpha Z{)}^3$ correction.

    hep-phPRD(2026)·3 citations
21. 21*

    Molecular states $J/\psi B_c^{+}$ and ${\eta }_c{B}_c^{\ast +}$

    S. S. Agaev🇦🇿 · K. Azizi🇮🇷 · H. Sundu🇹🇷

    Hadronic molecules $\mathfrak{M}=J/\psi B_c^{+}$ and $\tilde{\mathfrak{M}}={\eta }_c{B}_c^{\ast +}$ are investigated in the framework of QCD sum rule method. These particles with spin-parities $J^{\mathrm{P}}=1^{+}$ have the quark contents $cc\overline{c}\overline{b}$. We compute their masses and current couplings and find that they are numerically very close to each other coinciding within accuracy of the sum rule method. Therefore, we concentrate on the molecule $J/\psi B_c^{+}$ and explore features of this state in a detailed form. Our prediction $m=(9740\pm 70)\mathrm{MeV}$ for its mass means that $\mathfrak{M}$ easily decays to pairs of ordinary mesons through strong interactions. There are two mechanisms responsible for transformations of $\mathfrak{M}$ to conventional mesons. The fall-apart mechanism generates the dominant decay channels $\mathfrak{M}\to J/\psi B_c^{+}$ and $\mathfrak{M}\to {\eta }_c{B}_c^{\ast +}$. Annihilation of $\overline{c}c$ quarks triggers subdominant processes with various final-state $B$ and $D$ mesons: Six of such channels are considered in this work. The partial widths all of decays are computed using the three-point sum rule approach. The width $\Gamma [\mathfrak{M}]=(121\pm 17)\mathrm{MeV}$ of the hadronic axial-vector molecule $\mathfrak{M}$, as well as its mass provide valuable information for running and future experiments.

    hep-phhep-exhep-latNPB(2026)·2 citations
22. 22*

    Partonic Entropy of the Proton from DGLAP Evolution

    Krzysztof Golec-Biernat🇵🇱

    We investigate the concept of partonic entropy of the proton within the Dokshitzer--Gribov--Lipatov--Altarelli--Parisi (DGLAP) evolution scheme of collinear parton distributions. We show that such entropy increases monotonically with the evolution scale. The mechanism underlying this growth is illustrated using a simplified model of DGLAP evolution, highlighting the importance of including saturation effects at small x in the evolution of parton distributions, which tame the otherwise unbounded growth of partonic entropy. Based on existing literature, we present two simplified models of parton saturation at small x. In one of these models, partonic entropy is identified with entanglement entropy and proposed as an experimentally testable observable.

    hep-ph3 citations
23. 23*

    From QCD-Based Descriptions to Direct Fits: A Unified Study of Nucleon Electromagnetic Form Factors

    Hossein Vaziri🇮🇷 · Mohammad Reza Shojaei🇮🇷 · Pere Masjuan🇪🇸

    We present a detailed study of the nucleon electromagnetic form factors in the spacelike region by combining three complementary approaches: two GPD-based contributions and a vector-meson exchange component. By fitting experimental data, we extract the optimal weights and shape parameters describing the proton and neutron form factors. Global Padé-based fits are then constructed for four distinct groups of form factors, starting from local Taylor expansions and yielding stable analytic parametrizations over the analyzed $t$ range. The combined framework provides an accurate and physically motivated description of nucleon structure within a controlled model-dependent setting across a wide range of momentum transfers.

    hep-phEur.Phys.J.ST(2026)·3 citations
24. 24*

    Discovery prospects for photophobic axion-like particles at a 100 TeV proton--proton collider

    Zilong Ding🇨🇳 · Jiaojiao Feng🇨🇳 · Ying-nan Mao🇨🇳 · Kechen Wang🇨🇳 · Yiheng Xiong🇨🇳

    We study heavy photophobic axion-like particles (ALPs) in the limit of an effectively vanishing diphoton coupling, $g_{a\gamma \gamma }\simeq 0$, for which diphoton production and decay are suppressed and collider phenomenology is driven by electroweak interactions ($aWW$, $aZ\gamma$, $aZZ$). We perform detector-level searches at a future $\sqrt{s}=$ 100 TeV $pp$ collider (SppC/FCC-hh), with an integrated luminosity of $\mathcal{L}=$ 20 ab${}^{-1}$. We consider $a\to Z\gamma$ and $a\to W^{+}{W}^{-}$ decays. For $pp\to jja$ we include both $s$-channel electroweak exchange and vector boson fusion (VBF)-like topologies, while the tri-$W$ signature arises from associated production $pp\to W^{\pm }a$ (via $s$-channel exchange) followed by $a\to W^{+}{W}^{-}$. We analyze three final states--$Z\gamma jj$ with $Z\to {\ell }^{+}{\ell }^{-}$, tri-$W$ ($W^{\pm }{W}^{\pm }{W}^{\mp }$) with same-sign dimuons plus jets, and $W^{+}{W}^{-}jj$ with opposite-sign, different-flavor dilepton ($e^{\pm }{\mu }^{\mp }$) plus jets. Among the two $WW$ final states, the VBF-assisted $jja(\to W^{+}{W}^{-})$ channel overtakes the purely $s$-channel tri-$W$ mode for $m_a\stackrel{>}{\sim }$ 1 TeV, reflecting 100~TeV signal/background kinematic shifts beyond naive energy/luminosity rescaling. A boosted-decision-tree (BDT) classifier built from kinematic observables provides the final signal--background separation, using detector-level simulations of signal and high-statistics SM backgrounds. At $\sqrt{s}=100$ TeV and $\mathcal{L}=$ 20 ab${}^{-1}$, we present discovery sensitivities to the ALP--$W$ coupling $g_{aWW}$ over $m_a\in [100,7000]$ GeV. In parallel, we report model-independent discovery thresholds on $\sigma \times \mathrm{Br}$ for $pp\to jja$ with $a\to Z\gamma$ and $a\to W^{+}{W}^{-}$, as well as for associated production $pp\to W^{\pm }a$ with $a\to W^{+}{W}^{-}$....

    hep-phhep-ex2 citations
25. 25*

    Muonphilic asymmetric dark matter at a future muon collider

    Arnab Roy🇦🇺 · Raymond R. Volkas🇦🇺

    We explore phenomenological constraints on, and future muon collider sensitivities to, the parameter spaces of various muonphilic portals to fermionic asymmetric dark matter (ADM). Both WEFT-level dimension-6 effective operators and two UV models based on gauged $L_{\mu }-L_{\tau }$ are considered. One of the latter features a vector coupling to the dark matter and the other an axial vector coupling. The ADM criterion that at least $99\%$ of the dark matter relic density is asymmetric is also imposed. We identify which of these scenarios are currently allowed by direct detection and collider constraints, and then determine how much more of the parameter space could be probed by 3 and 10 TeV muon colliders with 1 ab${}^{-1}$ of data. For the UV models, the constraints from $g-2$ of the muon are included. The future sensitivity curves due to neutron star heating considerations are also depicted. We present results for both the few-GeV dark matter mass regime motivated by ADM approaches to the ${\Omega }_b\simeq {\Omega }_{\text{DM}}/5$ coincidence problem, and for larger masses in the context of more general ADM.

    hep-phhep-exJHEP(2026)·2 citations
26. 26*

    Constraints on SMEFT operators from $Z\to \mu \mu bb$ decay

    Zijian Wang🇨🇳 · Tianyi Yang🇨🇳 · Tianyu Mu🇨🇳 · Andrew Levin🇨🇳 · Qiang Li🇨🇳

    The Standard Model Effective Field Theory (SMEFT) provides a systematic framework to probe indirect effects of heavy new physics via precision measurements. While SMEFT constraints have been extensively studied using purely leptonic $Z$ decays and inclusive $Z$ production, mixed leptonic-hadronic modes remain largely unexplored. In this work, we analyze $Z\to \mu \mu bb$ decays within the SMEFT framework, deriving constraints on dimension-six operators that affect four-fermion interactions between leptons and bottom quarks, as well as $Z$-fermion couplings. Signal and background events are simulated with state-of-the-art Monte Carlo tools, including detector effects such as $b$-tagging, and limits on the relevant Wilson coefficients are extracted using kinematic distributions and a profile likelihood approach. Our results provide complementary constraints to existing SMEFT studies and yield the first process-specific limits on flavor-resolved four-fermion operators involving muons and bottom quarks from $Z$ decays.

    hep-ph0 citations
27. 27*

    Complex scalar dark matter with effective Higgs portals beyond radiation domination

    Manimala Mitra🇮🇳 · Dipankar Pradhan🇮🇳 · Subham Saha🇮🇳

    The increasingly stringent bounds on the Higgs-portal coupling, arising from dark matter (DM) direct-detection searches, confront the minimal renormalizable complex scalar DM scenario with thermal production, where freeze-out occurs in the standard radiation-dominated era. This limitation can be alleviated by introducing a dimension-5 Higgs-portal operator in the minimal renormalizable complex scalar DM model and/or by modifying the standard cosmological history of the Universe. In this article, we analyze complex scalar DM production in both the reheating and radiation-dominated epochs within an effective field theory (EFT) framework. While both scenarios exhibit sizeable regions of parameter space consistent with existing constraints, freeze-out during reheating opens up additional viable regions that are otherwise ruled out by DM overabundance in the radiation-dominated scenario. Notably, the renormalizable Higgs-portal coupling is constrained by relic density, direct- and indirect-detection limits, whereas the EFT coupling associated with the dimension-5 operator is constrained by relic density and indirect-detection bounds arising from DM semi-annihilation. We further study the production cross section of complex scalar DM at hadron and lepton colliders.

    hep-phPRD(2026)·2 citations
28. 28*

    Azimuthal asymmetry in $J/\psi +\gamma$ and $J/\psi +J/\psi$ production in ultraperipheral heavy-ion collisions at LHC

    Yu Jia🇨🇳 · Wen-Long Sang🇨🇳 · Xiaonu Xiong🇨🇳 · Jian Zhou🇨🇳 · Ya-jin Zhou🇨🇳

    Two-photon collision in ultraperipheral heavy-ion collisions (UPCs) provides a unique and powerful platform for probing QCD with linearly polarized quasi-real photons. While photon polarization effects have been recognized in dilepton and even in light hadrons production, their consequences for heavy quarkonium production remain unexplored. In this work we investigate for the first time the $\gamma \gamma \to J/\psi +\gamma (J/\psi )$ channels in Pb-Pb UPCs at the Large Hadron Collider (LHC), by integrating the non-relativistic QCD (NRQCD) factorization approach with the transverse-momentum-dependent (TMD) photon distributions. Based on the helicity amplitudes at lowest order in strong coupling and velocity expansion, we predict sizable $\cos (2\varphi )$ and $\cos (4\varphi )$ azimuthal asymmetries arising from the interference of linearly polarized photon states. These azimuthal-dependent observables, defined as the ratios of weighted to unweighted cross sections, are expected to be stable against including the higher-order radiative corrections and varying nonperturbative NRQCD matrix elements, thus offering a fresh test of quarkonium production mechanism and the photon TMD structure in the ultrarelativistic limit.

    hep-ph3 citations
29. 29*

    125 GeV Higgs boson rare decays in a flavor-dependent $U(1{)}_F$ model

    Zhan Cao🇨🇳 · Jin-Lei Yang🇨🇳 · Ti-Bin Hou🇨🇳 · Tai-Fu Feng🇨🇳

    In this work, we analyze the Higgs boson decay channels, specifically, $h\to \gamma \gamma$, $h\to V{V}^{\ast }$ (with $V=Z,W$), and $h\to f\bar{f}$ (for $f=b,c,\tau$) within the flavor-dependent $U(1{)}_F$ model (FDM). We also investigate processes induced by flavor-changing neutral currents, including the decays $\bar{B}\to X_s\gamma$ and $B_s^0\to {\mu }^{+}{\mu }^{-}$, the top quark decays $t\to ch$ and $t\to uh$, and the lepton flavor-violating decays $\tau \to 3e$, $\tau \to 3\mu$, and $\mu \to 3e$. Furthermore, we incorporate the electroweak precision observables constraints via the S, T, and U parameters. Compared to the Standard Model, the scalar sector of the FDM is extended by two Higgs doublets and one Higgs singlet, which affects the 125 GeV Higgs properties significantly. Meanwhile, the decays $h\to Z\gamma$, $h\to MZ$, and $h\to M\gamma$ (where $M$ is a vector meson $(\rho ,\omega ,\varphi ,J/\Psi ,{\rm Y})$ of the Standard-Model-like Higgs are studied, and we illustrate how changes in the scalar sector and the Yukawa coupling influence the signal strengths for the 125 GeV Higgs decay channels and the Higgs mass in the FDM.

    hep-phPRD(2026)·1 citation
30. 30*

    Fine-tuning final state interactions model in NuWro Monte Carlo event generator

    Hemant Prasad🇵🇱 · Jan T. Sobczyk🇵🇱 · Rwik Dharmapal Banerjee🇵🇱 · J. Luis Bonilla🇵🇱 · Krzysztof M. Graczyk🇵🇱 · Beata E. Kowal🇵🇱 · Artur M. Ankowski🇵🇱

    Recent experimental data from MINERvA on transverse kinematics observables across four different nuclear targets - carbon, oxygen, iron, and lead - have been utilized to refine the modeling of final state interaction effects in the NuWro Monte Carlo neutrino event generator. For this purpose, we have developed an event reweighting tool for future applications to adjust the strength of final-state interactions. This study highlights the requirement for stronger nucleon reinteractions than previously assumed, but it still falls within the uncertainty range observed in a study comparing proton transparency measurements. This conclusion has significant implications for both experimental and theoretical work involving NuWro.

    hep-phnucl-thPRD(2026)·1 citation
31. 31*

    Prospects for detecting charged long-lived BSM particles at MoEDAL-MAPP experiment: A mini-review

    Rafał Masełek🇵🇱 · Kazuki Sakurai🇵🇱

    The search for physics beyond the Standard Model at the Large Hadron Collider is expanding to include unconventional signatures such as long-lived particles. This mini-review assesses the prospects for detecting electrically charged long-lived particles using the MoEDAL-MAPP experiment. We synthesize findings from recent studies that evaluate sensitivity to supersymmetric models, radiative neutrino mass scenarios, and generic multiply charged objects. A key component of this review is the comparative analysis of MoEDAL's reach against the general-purpose ATLAS and CMS experiments. We conclude that while MoEDAL is constrained by lower integrated luminosity, its passive, background-free detection methodology offers a unique advantage. Specifically, the experiment provides complementarity to the major detectors, particularly for signals involving slow-moving particles and stable states with intermediate electric charges.

    hep-phhep-ex4 citations
32. 32*

    Analytical results for the C-angularity soft function at NNLO

    Alexander Bennett🇬🇧 · Emmet P. Byrne🇬🇧 · Jonathan R. Gaunt🇬🇧 · Elsa C. Lang🇬🇧

    We compute the soft function at NLO and NNLO for a one-parameter family of event shapes we call C-angularity. This family contains C-parameter as a specific choice of the parameter, in close analogy with how conventional angularity contains thrust as a special case. By construction, C-angularity and angularity coincide in the collinear limit such that the anomalous dimensions are equal. However, unlike angularity, C-angularity is a continuously differentiable function of the final state momenta, which makes the analytic calculation of the C-angularity soft function simpler. We obtain analytical results for the C-angularity soft function and anomalous dimension as an expansion in the C-angularity parameter $a$, to third and fourth order in $a$ respectively. These expansions yield results that are accurate at the few per mille level for $-1\le a<1$.

    hep-phJHEP(2026)·1 citation
33. 33*

    Are 2HDMs with a gauged $U(1)$ symmetry alive?

    Yuanchao Lou🇨🇳 · Takaaki Nomura🇨🇳 · Xinran Xu🇨🇳 · Kei Yagyu🇯🇵

    We investigate the phenomenology of 2 Higgs doublet models (2HDMs) with a new $U(1)$ gauge symmetry, $U(1{)}_X$, by which flavor changing neutral currents are forbidden at tree level. As an important consequence of the spontaneous breaking of both the $U(1{)}_X$ and electroweak symmetries by electroweak vacuum expectation values, upper limits appear on masses of an additional gauge boson $Z^{\prime }$ and extra Higgs bosons which are less than the TeV scale. In addition, the standard model (SM) like Higgs boson $h$ and a heavier Higgs boson $H$ mainly decay into a pair of $Z^{\prime }$ which induces four lepton final states. These new decay modes cannot be suppressed by taking no $Z$-$Z^{\prime }$ mixing and/or the Higgs alignment limit. We find that the minimum setup of these 2HDMs has been excluded by current data for four lepton searches at LHC. Such severe constraints can, however, be avoided by introducing a pair of vector-like fermions $\chi$ which are singlet under the SM symmetry but charged under $U(1{)}_X$, and can be a candidate of dark matter. Thanks to the existence of $\chi$, $Z^{\prime }$ can mainly decay into $\chi \bar{\chi }$ instead of SM leptons. As benchmark models, we consider the $U(1{)}_H$ and $U(1{)}_R$ models realized by fixing specific $U(1{)}_X$ charges, and find regions of parameter space allowed by theoretical and current experimental constraints. We clarify that $m_H\in [160,220]$ GeV and $\tan \beta \in [3,4.4]$ are allowed in the $U(1{)}_H$ model, while $m_H\in [160,380]$ GeV and $\tan \beta \in [1.6,4.4]$ are allowed in the $U(1{)}_R$ model. In both the models, the $Z^{\prime }$ mass is constrained to be $100\text{GeV}\lesssim m_{Z^{\prime }}\lesssim 110$ GeV. Such a quite limited parameter space can further be explored at future collider experiments, e.g., High-Luminosity LHC and lepton colliders.

    hep-phJHEP(2026)·0 citations
34. 34*

    False-vacuum decay and flaws in Frampton's model of the origin of life

    Andrzej Czarnecki🇨🇦 · Jishnu Khanna

    We briefly review false-vacuum decay and examine a recent proposal by Frampton to model the origin of the first single-celled organism (SCO) as a phase transition between no-life and life vacua. In his calculation the exponent $n$ entering the probability $P_{\mathrm{SCO}}\sim 10^{-n}$ has dimensions of inverse time: it is an energy barrier divided by the Planck constant, rather than a dimensionless tunnelling action. The resulting probability is mathematically ill-defined and does not determine a tunnelling rate. Apart from this dimensional issue, the assumed initial configuration, a toroidal structure made of long molecules, and its treatment in empty space are inconsistent with soft-matter physics and with the hot, collisional environment expected for prebiotic chemistry. Consequently, the claimed exponential suppression of biogenesis, and the inference that extraterrestrial life is likely absent, are not supported.

    hep-phActa Phys.Polon.Supp.(2026)·1 citation
35. 35*

    Simulation of tau decays, ambiguities and anomalous couplings

    Zbigniew Was🇵🇱 · Ananya Tapadar🇵🇱 · J. M. John🇵🇱 · S. Banerjee🇺🇸

    From the perspective of low energy tau decays and radiative corrections in decays, not much has changed since the last, Tau23 conference. Also, TAUOLA, tau decay library, and PHOTOS for radiative corrections in decays have not changed much, neither for QED nor for New Physics processes application. Progress was in the domain of flexibilities for applications and in the domain of New Physicists. There was progress with use of exclusive exponentiation (KKMC Monte Carlo) to evaluate quality of tau pair formation and decay factorization, with Collins-Soper and Mustraal frames. Ambiguities for New Physics or other processes could be thus addressed. Associated projects of KKMC f77 and KKMCee C++, are presented: (i) ${\pi }^{+}{\pi }^{-}$ pair production at Belle II energies, interesting input for Pi_gammagamma(s), (ii) attribution of helicity like labels for taus in simulated HepMC3 format events, (iii) also tau polarimetric vectors prepared for user application of New Physics.

    hep-ph0 citations
36. 36*

    Defect Formation in NaI Crystals: A Novel Pathway to Dark Matter Detection

    G. Angloher · M. R. Bharadwaj · A. Böhmer · M. Cababie · I. Colantoni · I. Dafinei · N. Di Marco · C. Dittmar · F. Ferella · F. Ferroni · S. Fichtinger · A. Filipponi and 34 other authors

    Sodium iodide (NaI) is a widely used scintillator in direct dark matter searches. In particular, NaI-based cryogenic scintillating calorimeters have emerged as promising candidates, like in the COSINUS experiment, for testing the annually modulating signal reported by DAMA/LIBRA. In this study, we investigate defect formation within NaI crystals and its impact on the dark matter detection signal. Using molecular dynamics simulations and density functional theory techniques, we simulate a DM particle collision on an NaI crystal, focusing on the possible defects formation and their structural and electronic properties. Our analysis includes a detailed study of the electronic states associated with the interstitial atoms and vacancies, the energetic cost of defect formation, and the anisotropic threshold displacement energy. Finally, we highlight the potential to exploit dark matter-induced defects as a novel detection channel, enabled by the introduction of new states within the electronic band gap.

    hep-phastro-ph.IMPRD(2026)·1 citation
37. 37*

    Perturbative results for the matrix elements of the vector current and the role of different infrared regulators

    Alessio Carmelo Alvaro🇮🇹 · Ignacio Castelli🇺🇸 · Cédric Lorcé🇫🇷 · Andreas Metz🇺🇸 · Barbara Pasquini🇮🇹 · Simone Rodini🇮🇹

    We investigate the twist-2 unpolarized generalized parton distributions (GPDs) of quarks for an on-shell gluon target in quantum chromodynamics. These GPDs parametrize the leading-twist matrix elements of the nonlocal light-like flavor-singlet vector current. We compute them at one-loop accuracy in perturbation theory using a quark mass and dimensional regularization as infrared regulators. In particular, we discuss the limit of vanishing momentum transfer. The present work extends our previous related study on the axial current.

    hep-phnucl-thPLB(2026)·0 citations
38. 38*

    Scrutinizing the KNT model with vacuum stability conditions

    Tim Huesmann🇩🇪 · Michael Klasen🇩🇪 · Vishnu P.K🇦🇺

    The Krauss-Nasri-Trodden (KNT) model provides a unified framework for addressing the smallness of neutrino masses (by a three-loop radiative mechanism) and the dark matter abundance (via thermal freeze-out) simultaneously. In this work, we investigate the implications of renormalization group effects on the model's parameter space. To this end, we perform a Markov Chain Monte Carlo analysis to identify the viable regions of parameter space that is consistent with all the relevant experimental and theoretical constraints at low energies. We show that a significant portion of the low-energy viable region is incompatible with the vacuum stability conditions once the renormalization group effects are taken into account. Most of the remaining parameter space of the model can be probed in future charged lepton flavor violating experiments.

    hep-phhep-ex0 citations
39. 39*

    Soft and Jet functions for SCET at four loops in QCD

    Saurav Goyal🇮🇳 · Sven-Olaf Moch🇩🇪 · Vaibhav Pathak🇮🇳 · V. Ravindran🇮🇳

    Soft-Collinear Effective Theory is a framework for systematically organizing and resumming the logarithmic contributions that occur in high-energy reactions. It provides a factorized description of cross sections in terms of hard, jet, soft, and beam functions. As the latter are universal, they can be obtained from the well-known perturbative results in quantum chromodynamics (QCD) for deep-inelastic scattering, Drell-Yan and Higgs boson productions. Using the recent results ~\cite{Kniehl:2025ttz} on four-loop eikonal $(f^I)$ and collinear anomalous dimensions $(B^I)$ for quarks and gluons, $I=q,g$, as well as perturbative results from previous orders, we present four-loop predictions for the quark and gluon soft and jet functions. They constitute an important component of the $N$-jettiness subtraction method at ${\mathrm{N}}^4\mathrm{LO}$ accuracy in QCD, which eventually may enable the calculation of fully-differential cross sections at higher orders.

    hep-ph2 citations
40. 40*

    Coupled-channel Omnès matrix for the $D$-wave isoscalar $\pi \pi /K\bar{K}$ system and its application to $J/\psi \to {\pi }^0{\pi }^0\gamma ,K_S{K}_S\gamma$

    Igor Danilkin🇩🇪 · Oleksandra Deineka🇩🇪 · Emilie Passemar🇺🇸 · Marc Vanderhaeghen🇩🇪

    In this work, we construct the $D$-wave isoscalar $\pi \pi /K\bar{K}$ coupled-channel Omnès matrix, formulated to satisfy unitarity, analyticity, and the appropriate asymptotic behavior. We employ a two-channel $K$-matrix model containing poles associated with the $f_2(1270)$ and $f_2^{\prime }(1525)$ resonances. The resulting unitary scattering matrix, which reproduces the experimental $\pi \pi \to \pi \pi$ and $\pi \pi \to K\bar{K}$ data and PDG information, serves as input to the homogeneous two-channel Muskhelishvili-Omnès equation. We compare our Omnès matrix with previous constructions based on $\pi \pi \to K\bar{K}$ phases extracted from sums of Breit-Wigner amplitudes. The Omnès matrix developed here provides a reliable dispersive input for form-factor calculations and resonance studies in the tensor-meson sector. As an application, we show that it enables a simultaneous and accurate description of the BESIII $J/\psi \to {\pi }^0{\pi }^0\gamma$ and $J/\psi \to K_S{K}_S\gamma$ spectra in the $J=2$ electric-dipole (E1) partial wave.

    hep-phPLB(2026)·3 citations
41. 41*

    The Effect of Hadronic Matter on Parton Energy Loss

    Ritoban Datta🇺🇸 · Abhijit Majumder🇺🇸

    Modified thermal distributions (dispersion relations) are introduced within both the MATTER and LBT event generators used to describe jet modification in a heavy-ion collision, within the JETSCAPE framework. Hard partons, propagating through dense matter, scatter off the partonic substructure of the medium, leading to stimulated emission, accompanied by recoiling medium partons. We introduce a simple modification, a multiplicative $(1+a/T)$ correction to the dispersion relation of quarks and gluons (equivalent to an effective fugacity). This leads to calculated transport coefficients (e.g. $\hat{q}/T^3$) showing the expected behavior of depreciating at lower temperatures, including within the hot hadronic gas. This simple modification recovers the light-like dispersion relations at high temperatures, and introduces an excess depreciation factor for parton populations at lower temperatures, allowing partonic energy loss and recoil calculations to be extended into the hadronic phase. This modified distribution, in combination with initial state cold nuclear matter effects (shadowing), is used to simultaneously describe the nuclear modification factor and elliptic anisotropy of jets and leading hadrons, over multiple centralities and collision energies.

    hep-phhep-exnucl-exnucl-th2 citations
42. 42*

    Axion domain walls and thermal friction

    Amedeo M. Favitta🇮🇹

    The post-inflationary Peccei-Quinn symmetry-breaking scenario provides a rich theoretical framework to study axion dark matter production through the dynamics oftopological defects. Accurate predictions for the axion abundance require a detailed understanding of the formation and evolution of cosmic strings and domain walls, which are inevitably produced in this scenario. Most existing studies rely on large-scale numerical simulations of the classical equations of motion, which are subject to significant systematic uncertainties. In this contribution, we briefly review the main features of the post-inflationary scenario and the current limitations in the literature, and present preliminary results from a new analytical framework for axion domain wall networks. Our approach is based on nonequilibrium quantum field theory. It employs the two-particle-irreducible effective action to derive effective Fokker-Planck equations for macroscopic quantities such as the average energy density and root-mean-square velocity of the network.We discuss the relevance of thermal, self-interactions, plasma-induced and quantum effects for cosmological axion abundance estimates, with applications to QCD axions and high-mass axion-like particles.

    hep-phPoS(2026)·0 citations
43. 43*

    Dark Recipe for the First Giants: From Population III Stars to Early Supermassive Black Holes via Dark Matter Capture

    Sulagna Bhattacharya🇮🇳 · Debajit Bose🇮🇳 · Basudeb Dasgupta🇮🇳 · Jaya Doliya🇮🇳 · Ranjan Laha🇮🇳

    The presence of supermassive black holes (SMBHs) at high redshifts ($z>5$), as revealed by James Webb Space Telescope (JWST), challenges standard black hole (BH) formation scenarios. We propose a mechanism in which non-annihilating dark matter (DM) with non-gravitational interactions with the Standard Model (SM) particles accumulates inside Population III (Pop III) stars, inducing their premature collapse into BH seeds having the same mass as the parent star. Owing to their early formation, these seeds can accrete for longer periods and grow into the SMBHs observed at early cosmic times. Focusing on spin-dependent (SD) DM-proton interactions, we identify regions of parameter space that account for the observed high-redshift SMBH population, their mass function, and the SMBH-stellar mass relation. Portions of this parameter space are testable by forthcoming direct detection experiments. The scenario may lead to distinctive gravitational wave (GW) signatures from SMBH mergers, accessible to Laser Interferometer Space Antenna (LISA) and pulsar timing array (PTA) observations.

    hep-phastro-ph.CO1 citation
44. 44*

    Strong Coupling Constant Determination from the new CTEQ-TEA Global QCD Analysis

    Alim Ablat🇨🇳 · Sayipjamal Dulat🇨🇳 · Marco Guzzi🇺🇸 · Joey Huston🇺🇸 · Kirtimaan Mohan🇺🇸 · Pavel Nadolsky🇺🇸 · Dan Stump🇺🇸 · C.-P. Yuan🇺🇸

    We present a new determination of the strong coupling constant ${\alpha }_s$ from a global QCD analysis CT25 of parton distribution functions (PDFs) that incorporates high-precision experimental measurements from the Run-2 of the Large Hadron Collider together with a large sample of other measurements over a wide interval of energies. This work addresses two objectives: providing an up-to-date determination of ${\alpha }_s$ using NNLO calculations and a sensitive nucleon data set within a self-consistent framework, and critically assessing the robustness of the ${\alpha }_s(M_Z)$ extraction in light of systematic uncertainties as well as correlations of ${\alpha }_s(M_Z)$ with the functional forms of PDFs and other model parameters. In regard to the uncertainty assessment, we demonstrate that some commonly used criteria, including the dynamical tolerance and Bayesian hierarchical models, may produce significantly different or even unstable estimates for the net ${\alpha }_s$ uncertainty, and we introduce a concept of \textit{data-clustering safety} that the replicable uncertainty estimates must satisfy. Based on this in-depth examination of the CT25 global hadronic data set using a combination of analysis methods, and after demonstrating a weak correlation between ${\alpha }_s$ and the functional forms of CT25 PDF parametrizations, we find ${\alpha }_s(M_Z)=0.1183_{-0.0020}^{+0.0023}$ at the 68\% credibility level.

    hep-ph8 citations
45. 45*

    Extracting light-cone wave functions from covariant amplitudes: a detailed study in scalar field theory

    Stéphane Munier🇫🇷

    We propose a conjectured formula that systematically maps covariant off-shell amplitudes to light-cone wave functions in scalar field theory. Through an explicit comparison at one-loop accuracy, we establish its equivalence to the light-cone perturbation theory series, thereby validating the conjecture at this order. Applying this formula, we efficiently re-derive wave functions from known covariant amplitudes, bypassing both the conceptual complexities of light-cone quantization and the technical challenges of perturbative calculations in this framework. In addition to simplifying computations, this approach opens new avenues for applications in gauge theories and deeper explorations of the fundamental equivalence between covariant and light-cone quantization.

    ↳ hep-thhep-phPRD(2026)·1 citation
46. 46*

    Resurgence in the two-field scalar and spinor Quantum Electrodynamics Euler-Heisenberg Lagrangian

    Drishti Gupta🇺🇸 · Arun Thalapillil🇮🇳

    We present the first systematic resurgent analysis of the Euler-Heisenberg Lagrangian in spinor and scalar quantum electrodynamics for the most general constant background field configuration. In contrast to the extensively studied single-field cases, the two-field case exhibits unique asymptotic structures, leading to a substantially richer pattern of singularities in the Borel plane. Explicit large-order asymptotic formulas for the weak-field coefficients in both spinor and scalar quantum electrodynamics are derived. These reveal a nontrivial interplay between alternating and non-alternating factorial growth, governed by distinct structures associated with electric and magnetic contributions, and smoothly interpolating between the known single-field limits. Using Borel dispersion techniques, we demonstrate that the complete instanton structure underlying Schwinger pair production in two-field backgrounds is encoded in the divergent perturbative coefficients. We then construct resurgent approximants using Padé-Borel and Padé-Conformal-Borel resummation schemes adapted to the two-field case. For the spinor case, conformal improvement results in a significant enhancement in reconstructing both the real and imaginary parts of the effective Lagrangian across a wide range of field ratios, accurately capturing the subtle sign-changing features in the strong-field regime while in the scalar case, it yields minor improvement. Detailed comparisons with exact special-function representations demonstrate the reliability of reconstructions from a modest number of weak-field coefficients. This work establishes a natural completion of the resurgence programme for constant electromagnetic backgrounds, providing a robust analytic framework for exploring nonperturbative physics and strong-field phenomena in spinor and scalar quantum electrodynamics, from finite perturbative data.

    ↳ hep-thhep-exhep-phEPJC(2026)·1 citation
47. 47*

    Primordial black holes within Higgs hybrid metric-Palatini approach

    Brahim Asfour🇲🇦 · Farida Bargach🇲🇦 · Yahya Ladghami🇲🇦 · Ahmed Errahmani🇲🇦 · Taoufik Ouali🇲🇦

    In this paper, we investigate the production of primordial black holes (PBHs) during the radiation-dominated era. The collapse of significant density perturbations originating from large primordial scalar fluctuations generated during inflation can lead to the formation of primordial black holes. In our study, we adopt the Higgs hybrid metric-Palatini model as our framework, in which the inflaton field and the Palatini curvature are non-minimally coupled. To achieve our objective, we analyze the behavior of the primordial curvature power spectrum, which exhibits a large enhancement at small scales corresponding to large wavenumbers $k$. Furthermore, we examine the probability of PBHs formation by studying the mass variance, $\sigma (M_{PBH})$, and the mass fraction of the total energy density collapsing into PBHs, $\beta (M_{PBH})$. The evolution of both functions is consistent with current observational constraints. Finally, we investigate the abundance of primordial black holes as a dark matter candidate. We found that they can account for the totality or a fraction of the current dark matter content, depending primarily on the values of the coupling constant and the e-folds number.

    ↳ astro-ph.COgr-qchep-phEPJC(2026)·0 citations
48. 48*

    Exact solutions for a complex scalar field under discrete symmetry

    D. Bazeia🇧🇷 · R. Menezes🇧🇷 · G.S. Santiago🇧🇷

    We report on the presence of families of exact solutions for a complex scalar field that behaves according to the rules of discrete $Z_N$ symmetry. Since the family of models is exactly solved, the results appear to be of interest to integrability, to build junctions and networks of localized structures and to describe scalar dark matter in high energy physics.

    ↳ hep-thhep-phnlin.PS0 citations
49. 49*

    Vacuum Decay around Black Holes formed from Collapse

    Giuseppe Rossi🇮🇱

    We re-examine the problem of vacuum decay in the presence of spherically symmetric black holes. Within the semiclassical approximation, we study configurations describing a bubble of true vacuum propagating outside a black hole formed from gravitational collapse. We find that the saddle point is dominated by a single energy state and that the dependence on the initial conditions in the stellar interior vanishes exponentially fast at late stages of the collapse. Prescriptions are given for implementing the corresponding boundary conditions in the eternal black-hole geometry. We find that vacuum decay can only be weakly catalyzed by the black hole, as the suppression exponent attains a minimum at a finite black-hole mass. In the limit of vanishing black-hole mass, the suppression smoothly approaches the flat-space result.

    ↳ hep-thhep-ph4 citations
50. 50*

    New Constraints on Cosmic-ray boosted Sub-GeV Dark Matter via Light Mediators

    Yang Yu🇨🇳 · Guan-Sen Wang🇨🇳 · Bo Zhang🇨🇳 · Tian-Peng Tang🇨🇳 · Bing-Yu Su🇨🇳 · Lei Feng🇨🇳

    Traditional direct detection experiments lack the sensitivity to probe the sub-GeV dark matter (DM), primarily due to the low energy of the expected nuclear recoils. In this work, we investigate cosmic-ray (CR) upscattering as a mechanism to accelerate DM particles to detectable velocities in underground experiments. By analyzing four models of DM-nucleon interactions -- namely scalar, vector, pseudoscalar, and axial-vector mediators -- we derive constraints on the coupling parameters using data from the LZ, XENON, and Borexino experiments, covering mediator mass from $10^{-6}$ to $1$ GeV. As the mediator mass varies, the shift in dominance between momentum transfer and mediator mass leads to a turnover in the constraints around $10^{-2}$--$10^{-3}\mathrm{GeV}$. Our results extend the reach of direct detection into the sub-GeV window and clarify the critical role of momentum dependence in light-mediator scenarios.

    ↳ astro-ph.HEhep-ph2 citations
51. 51*

    Precisely determining the ground state mass of Spin-3/2 ${\Omega }_{ccc}$ baryon from Lattice QCD

    Navdeep Singh Dhindsa🇮🇳 · Debsubhra Chakraborty🇮🇳 · Archana Radhakrishnan🇮🇳 · Nilmani Mathur🇮🇳 · M. Padmanath🇮🇳

    We present the most precise determination to date of the ground-state masses of the triply charmed baryons with both parities, obtained by continuum extrapolation and fully addressing the systematic uncertainties. The calculations are performed on six $N_f=2+1+1$ HISQ ensembles, generated by the MILC collaboration, with two complementary setups for the valence charm action, one using the HISQ action and the other using the overlap fermion action. Our prediction for the mass of the lowest two triply charmed spin-3/2 baryons are: $M_{{\Omega }_{ccc}}(3/2^{+})=4793(5)\left({}_{-8}^{+11}\right)$ MeV, and $M_{{\Omega }_{ccc}}(3/2^{-})=5094(12)\left({}_{-17}^{+19}\right)$ MeV.

    ↳ hep-lathep-exhep-phPoS(2026)·2 citations
52. 52*

    Neutron Star Equation of State with Nucleon Short-Range Correlations: A Concise Review and Open Issues

    Bao-Jun Cai🇨🇳 · Bao-An Li🇺🇸 · Yu-Gang Ma🇨🇳

    Nucleon short-range correlations (SRCs) and the associated high-momentum tail (HMT) in its momentum distribution $n(k)$ represent a universal feature of strongly interacting Fermi systems. In nuclear matter, SRCs arise primarily from the spin-isospin dependence of the tensor and short-range components of the nucleon-nucleon interaction, leading to a substantial depletion of its Fermi sea and a characteristic $k^{-4}$ tail populated predominantly by isosinglet neutron-proton pairs. These microscopic structures modify both the kinetic and interaction contributions to the Equation of State (EOS) of dense matter and thereby influence a broad range of neutron-star (NS) properties. This short review provides a streamlined overview of how SRC-induced changes in $n(k)$ reshape the kinetic EOS, including its symmetry energy part and how these effects propagate into macroscopic NS observables, including mass-radius relations, tidal deformabilities, direct Urca thresholds and core-crust transition. We summarize key existing results, highlight current observational constraints relevant for testing SRC-HMT effects, and outline open questions for future theoretical, experimental, and multimessenger studies of dense nucleonic matter.

    ↳ nucl-thastro-ph.HEhep-phhep-th+1Modern Physics Letters A, 2630005 (2026)·1 citation
53. 53*

    Poles from the conserved kinetic equation: The emerging gradient structure and causality riddle of relativistic hydrodynamics

    Sukanya Mitra🇮🇳

    In this work, the poles and the resulting dispersion spectra from the relativistic kinetic equation have been analyzed with the help of a proposed collision kernel that conserves both the energy-momentum tensor and particle current by construction. The dispersion relations, which originally come out in the form of logarithmic divergences, in the long wavelength limit exhibit the systematic gradient structure of the relativistic hydrodynamics. The key result is that, in the derivative expansion series, the spatial gradients appear in perfect unison with the temporal gradients in the non-local relaxation operator like forms. It is then shown that this dispersion structure, including non-local temporal derivatives, is essential for the preservation of causality of the theory truncated at any desired order.

    ↳ nucl-thgr-qchep-phhep-thPLB(2026)·0 citations
54. 54*

    Pion scattering in finite volume within the Inverse Amplitude Method

    A. Gómez Nicola🇪🇸 · R. Molina🇪🇸 · Julián A. Sánchez🇪🇸

    We study the effect of a finite volume for pion-pion scattering within Chiral Perturbation Theory (ChPT) and the Inverse Amplitude Method (IAM) in a $L^3$ box (rest frame). Our full ChPT calculation takes into account the discretization not only in the $s$-channel loops but also in the $t,u$- channels and tadpole contributions. Hence, not only the unitarity right-hand cut but also the left-hand one continuum contributions are calculated in the finite volume. A proper extension of the standard Veltman-Pasarino identities is needed, as well as a suitable projection on the internal space spanned by the irreducible representations (irreps) of the octahedral group, based on either a finite set of cubic harmonics or the matrices which represent the irreps properly. From the ChPT we construct the IAM in the internal space, which provides the full volume dependence of the interacting energy levels of two-pions scattering in the finite volume. Our results for various low-energy constants sets show sizable corrections with respect to previous analyses in the literature for $m_{\pi }L\lesssim 2$, being compatible with energy levels lattice data. We expect that our analysis and results will help to optimize the process of determination of energy levels and phase-shifts with higher accuracy.

    ↳ hep-lathep-phJHEP(2026)·2 citations
55. 55*

    Semiclassical Canovaccio for Composite Operators

    Oleg Antipin🇭🇷 · Jahmall Bersini🇨🇭 · Jacob Hafjall🇩🇰 · Giulia Muco🇩🇰 · Francesco Sannino🇩🇰

    We present a novel semiclassical framework tailored to determine the scaling dimensions of heavy neutral composite operators in conformal field theories (CFTs) which are inaccessible with other current methodologies. It utilizes the state-operator correspondence to map the desired scaling dimensions to the semiclassical energy spectrum of periodic homogeneous field configurations on a cylinder. As concrete applications, we provide detailed analyses for the ${\varphi }^4$ theory near four dimensions and ${\varphi }^6$ near three dimensions, semiclassically determining the full spectrum of neutral operators in the traceless symmetric Lorentz representations. Our methodology is presented pedagogically and is readily applicable to a vast class of CFTs.

    ↳ hep-thcond-mat.str-elhep-phJHEP(2026)·4 citations
56. 56*

    The new generation lunar gravitational wave detectors: sky map resolution and joint analysis

    Xiaolin Zhang🇨🇳 · Chengye Yu🇨🇳 · Haoran Li🇨🇳 · Sobhan Kazempour🇨🇳 · Mingqiu Li🇨🇳 · Sichun Sun🇨🇳

    Lunar-based gravitational-wave interferometry is a fascinating endeavor, and was proposed as a promising approach to bridge the observational gap between space-borne and ground-based detectors. In this work, we adopt the Fisher-matrix method to examine the angular-resolution performance of the newly proposed Crater Interferometry Gravitational-wave Observatory (CIGO) on the lunar crater rim near the north pole, together with TianQin and LISA, for monochromatic sources in the 0.1-10 Hz band. We find that above 0.1 Hz, CIGO achieves better localization accuracy than the other two space-based missions and dominates the combined detector network's performance, provided that lunar noise mitigation is achieved in the 0.1-2.87 Hz frequency range. We further explore an upgraded Tetrahedron configuration, TCIGO, with a fourth station at the bottom of a crater, which forms a regular tetrahedral constellation on the lunar surface. The result shows that TCIGO yields a five-fold improvement in angular-resolution capability over CIGO and gets better sky coverage across the target frequency band.

    ↳ gr-qcastro-ph.IMhep-phphysics.ins-detnpj Space Exploration volume 2, Article n…·4 citations
57. 57*

    The renormalization group invariants and exact results for various supersymmetric theories

    Konstantin Stepanyantz🇷🇺

    Some recent all-loop results on the renormalization of supersymmetric theories are summarized and reviewed. In particular, we discuss how it is possible to construct expressions which do not receive quantum corrections in all orders for certain $\mathcal{N}=1$ supersymmetric theories. For instance, in $\mathcal{N}=1$ SQED+SQCD there is a renormalization group invariant combination of two gauge couplings. For the Minimal Supersymmetric Standard Model there are two such independent combinations of the gauge and Yukawa couplings. We investigate the scheme-dependence of these results and verify them by explicit three-loop calculations. We also argue that the all-loop exact $\beta$-function and the corresponding renormalization group invariant can exist in the $6D$, $\mathcal{N}=(1,0)$ supersymmetric higher derivative gauge theory interacting with a hypermultiplet in the adjoint representation.

    ↳ hep-thhep-ph0 citations
58. 58*

    Scattering Amplitudes and Conservative Binary Dynamics at $O(G^5)$ without Self-Force Truncation

    Zvi Bern🇺🇸 · Enrico Herrmann🇺🇸 · Radu Roiban🇨🇭 · Michael S.Ruf🇺🇸 · Alexander V. Smirnov🇷🇺 · Sid Smith🇮🇹 · Mao Zeng🇬🇧

    We compute the complete potential-graviton contributions to the conservative radial action and scattering angle for two non-spinning bodies in general relativity, accurate through fifth order in Newton's constant and including second-order self-force (2SF) effects. The calculation is carried out in the scattering-amplitude framework, combining the double copy, effective field theory, and multi-loop integration techniques based on integration by parts and differential equations. To address a major computational bottleneck, we develop improved integration-by-parts algorithms that render calculations at this order tractable. The post-Minkowskian amplitude is presented as a series expansion, following the strategy used earlier in maximal supergravity. For the first self-force sector, which involves only polylogarithmic functions, we also provide a closed-form analytic expression. For the second self-force sector, as in earlier supergravity work, we find nontrivial cancellations among contributions related to integrals supported on Calabi-Yau geometry.

    ↳ hep-thgr-qchep-phPRL(2026)·37 citations
59. 59*

    Limits of applicability of holographic dual descriptions to QCD: virtuality and coherence

    Guy F. de Teramond🇨🇷

    Virtuality and coherence determine the limits of applicability of holographic concepts in QCD. In light-front quantization, the invariant mass controls the off-shell behavior of a physical process and thus provides a measure of its virtuality. In impact space, the corresponding quantity is the invariant transverse separation between quarks and gluons, $\zeta$, which is identified with the holographic coordinate $z$ in holographic light-front QCD. By embedding the internal structure of hadrons and implementing an effective superconformal symmetry, the mapping between quantum states and classical gravity -- central to the holographic principle -- yields new analytic insights into the strong-interaction dynamics responsible for the emergence of a confinement scale and the observed hadron spectrum. We show that the possible emergence of a gravity dual to physical QCD is restricted to the Regge limit of high-energy scattering, where many partonic degrees of freedom participate coherently. This criterion provides a quantitative definition of the domain of applicability of holographic QCD to dynamical processes and allows it to be tested directly against experimental results. By further enforcing analyticity together with exact QCD constraints at asymptotic infinity, the holographic framework can be consistently extended beyond the infrared domain. To illustrate this procedure, we briefly discuss recent work by the HLFHS collaboration, where the effective strong coupling was extended from the Regge-limit domain, through the near-perturbative transition region, and into the ultraviolet Bjorken-limit domain. The resulting scheme provides a unified and precise nonperturbative description of the strong coupling across all virtuality scales.

    ↳ hep-thhep-phPoS(2026)·1 citation
60. 60*

    Exploring the Limits of Machine Learning Classification of Neutron Star Matter Models

    Wasif Husain🇦🇺

    We investigate the extent to which supervised machine learning techniques can distinguish between neutron-star matter models using macroscopic and oscillation-related quantities derived from theoretical stellar configurations. Four representative matter scenarios nucleonic, hyperonic, dark matter admixed, and strange matter models are considered, and a synthetic dataset is constructed from solutions of the Tolman Oppenheimer Volkoff equations under fixed microphysical and transport assumptions. A shallow neural network classifier is trained on physically motivated features, including gravitational mass, stellar radius, and oscillation related quantities, to evaluate classification performance across the model space. Rather than aiming at unique composition inference, the analysis focuses on identifying regimes of distinguishability and intrinsic degeneracy between models. We find that certain matter scenarios can be separated under controlled assumptions, while others exhibit substantial overlap, reflecting fundamental similarities in their effective equations of state. These results demonstrate that machine learning provides a useful computational framework for mapping the limits of model classification in neutron-star studies, clarifying where inference is feasible and where it remains intrinsically model dependent. The methodology is readily extensible to more complex microphysics and to future multi messenger datasets.

    ↳ astro-ph.HEastro-ph.IMhep-ph0 citations
61. 61*

    Correlators are simpler than wavefunctions

    Nima Arkani-Hamed🇺🇸 · Ross Glew🇬🇧 · Francisco Vazão🇺🇸

    Recent works reveal a simplicity in equal-time correlators absent from wavefunctions. We show that it follows from the fact that correlators are full spacetime integrals, rather than half-spacetime integrals as for the wavefunction. This makes striking properties manifest: some wavefunction singularities are absent, factorization simplifies, and around every pole the Laurent expansion has vanishing first subleading term. Near the total-energy pole, the expansion to second order is generated by a differential operator on scattering amplitudes.

    ↳ hep-thgr-qchep-phPRL(2026)·14 citations
62. 62*

    Strongly Coupled Sectors in Inflation: Gapped Theories of Unparticles

    Yikun Jiang🇺🇸 · Guilherme L. Pimentel🇮🇹 · Chen Yang🇮🇹

    We consider a novel scenario for a strongly coupled spectator sector during inflation, that of a higher dimensional conformal field theory with large anomalous dimensions -- ``unparticles'' -- and compactify the extra dimensions. More specifically, we take generalized free fields in five dimensions, where the extra dimension is compactified to a circle. Due to the usual Kaluza-Klein mechanism, the resulting excitations carry properties of both particles and unparticles, so we dub this scenario ``gapped unparticles''. We derive a two-point function of the gapped unparticles by performing dimensional reduction. We then compute, in the collapsed limit, the four-point correlation function of conformally coupled scalars exchanging a gapped unparticle, which are used as seed functions to obtain the correlation function of primordial density perturbations. The phenomenology of the resulting correlators presents some novel features, such as oscillations with an envelope controlled by the anomalous dimension, rather than the usual value of 3/2. Depending on the value of the five-dimensional scaling dimension and effective mass of the gapped unparticles, we find a clear strategy to distinguish gapped unparticles from heavy massive scalars. If we assume the interactions are localized on a brane, gapped unparticles with different effective masses will share a universal coupling, and their exchanges produce an interesting interference pattern.

    ↳ hep-thastro-ph.COgr-qchep-phJHEP(2026)·15 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.