Wed·Apr 15, 2026Wednesday·April 15, 2026

1. 01*

   Operator structure of power corrections and anomalous scaling in energy correlators

   Hao Chen🇺🇸 · Yibei Li🇩🇪

   Energy correlators offer a clean probe of quantum chromodynamics, serving as an ideal laboratory to rigorously investigate non-perturbative power corrections. The recent discovery that linear corrections exhibit a universal anomalous scaling points to a deep, underlying theoretical structure. We uncover the quantum field-theoretic origin of this phenomenon in the energy-energy correlator using light-ray operators. Through an explicit loop calculation, we derive the one-loop anomalous dimension, revealing that the dijet operator must be combined with a specific triple-jet component. This provides a first-principles framework that connects operator theory with high-precision collider phenomenology.

   hep-phhep-th4 citations
2. 02*

   Baryogenesis and Dark Matter from non-thermally produced WIMPs

   Giorgio Arcadi🇮🇹 · Sarif Khan🇮🇳 · Agnese Mariotti🇩🇪

   We illustrate, via a simplified model, a scenario in which the baryon-asymmetry and, possibly the dark matter component of the Universe are simultaneously generated by the decay of a WIMP-like mother particle, in turn produced non-thermally during an epoch of Early Matter domination. We first consider the standard evolution of the Universe and introduce TeV-scale BSM particles, finding that this paradigm cannot produce enough baryon asymmetry. This deficiency can be resolved by considering a non-standard scenario, with a matter-dominated phase prior to radiation-domination. Finally, we include a dark matter candidate, which is non-thermally produced during the Early Matter domination. Our results demonstrate an interesting common origin of baryon asymmetry and Dark Matter, with the particle masses lying within the collider-detectable range, thanks to the presence of non-standard evolution in the early Universe.

   hep-ph0 citations
3. 03*

   The 3-3-1 Model: a natural framework for sub-MeV dark matter

   Vinicius Oliveira🇵🇹 · D. Cogollo🇧🇷 · A. Doff🇧🇷 · C. A. de S. Pires🇧🇷

   We show that the $\mathrm{SU}(3{)}_C\times \mathrm{SU}(3{)}_L\times \mathrm{U}(1{)}_N$ model with right-handed neutrinos naturally accommodates a viable sub-MeV dark matter (DM) candidate realized as pseudo-Goldstone boson that acquires tiny mass through gravitational effects. The observed relic abundance is obtained via freeze-in in a low-reheating temperature scenario, without requiring tiny couplings. The model operates at the TeV scale and remains testable at current and future collider experiments.

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

   Effect of $K^{\ast }$ meson magnetic dipole moment on the $e^{+}{e}^{-}\to K^{+}{K}^{-}{\pi }^0{\pi }^0$ cross section

   Luis A. Jiménez Pérez🇲🇽 · Antonio Rojas🇲🇽 · Genaro Toledo🇲🇽

   We explore the sensitivity of the $e^{+}{e}^{-}\to K^{+}{K}^{-}2{\pi }^0$ cross section to the magnetic dipole moment (MDM) of the $K^{\ast }$ vector meson. We describe the ${\gamma }^{\ast }\to 2K2\pi$ vertex using a vector meson dominance model, including the intermediate resonant contributions relevant for energies below 2.4 GeV. Using BaBar data for this process, we show that this observable is indeed sensitive to the MDM of the $K^{\ast }$; we obtain a central value for the MDM of ${\mu }_{K^{\ast }}=4.5$ and an upper bound of ${\bar{\mu }}_{K^{\ast }}=6.3$, in units of $e/2m_{K^{\ast }}$. We emphasize the need for higher precision data to provide a first data-driven determination of this parameter to confront it with theoretical predictions.

   hep-phnucl-thPRD(2026)·1 citation
5. 05*

   Two component pseudo-Nambu-Goldstone-boson dark matter

   Riasat Sheikh🇯🇵 · Takashi Toma🇯🇵 · Koji Tsumura🇯🇵

   We study a two-component pseudo-Nambu-Goldstone-boson (pNGB) dark matter (DM) model motivated by boosted dark matter (BDM). The model is based on a complex scalar field charged under a dark $\text{U}(1{)}_V$ gauge symmetry, with a softly broken global $\text{SU}(3{)}_g$ symmetry that is spontaneously broken. The pNGB nature suppresses DM--Nucleon scattering, while the residual $\text{U}(1{)}_3\times \text{U}(1{)}_{T_0}$ symmetry automatically stabilizes the two pNGB DM candidates and allows conversion of the heavier component into the lighter one. A central point is that the heavier or light component hierarchy is controlled by the two independent soft-breaking parameters that split the pNGB multiplet, so an abundant heavier component required for BDM can be obtained without introducing ad hoc hierarchies among independent portal coupling tuned to enable effective conversion. We analyze the relic abundance together with the constraints considered in this work, including Higgs invisible decays and perturbative unitarity, classify the coupled freeze-out dynamics, and assess the resulting BDM scattering cross section and flux.

   hep-ph0 citations
6. 06*

   Deciphering the nature of $P_{\psi s}^{\Sigma }$ pentaquarks in the light of their electromagnetic multipole moments

   Ulaş Özdem🇹🇷

   We calculate electromagnetic multipole moments of $\Sigma$-type strange hidden-charm pentaquarks $P_{\psi s}^{\Sigma }$ (isospin triplet ${\Sigma }^{+},{\Sigma }^0,{\Sigma }^{-}$) using QCD light-cone sum rules, with six (spin-1/2) and seven (spin-3/2) interpolating currents built from diquark-diquark-antiquark operators. We compute magnetic dipole $\mu$ for all channels and, for spin-3/2, electric quadrupole $\mathcal{Q}$ and magnetic octupole $\mathcal{O}$ moments (first computation), and give the first quark-flavor decomposition. Scalar diquark currents yield charm-dominated, flavor-insensitive moments ($\mu \in [-1.92,-1.21]{\mu }_N$ for spin-1/2, $|\mu |\lesssim 1.2{\mu }_N$ for spin-3/2), consistent with heavy-quark spin symmetry. Axial-vector diquark currents produce larger, flavor-sensitive moments with sign reversals governed by $e_u/e_d=-2$. For $\mathcal{Q}$, scalar-diquark currents give oblate deformations ($Q_0\approx -2.0\times 10^{-2}{\mathrm{fm}}^2$) dominated by charm, while two-axial-vector-diquark currents predict prolate values up to $Q_0=+8.0\times 10^{-2}{\mathrm{fm}}^2$, with sign reversal for $[su][uc]\bar{c}$ in two currents. Currents with scalar antiquark coupling yield a topology-independent octupole $\mathcal{O}\approx -0.25\times 10^{-3}{\mathrm{fm}}^3$, a lattice QCD benchmark. Comparison with constituent quark models identifies four discriminants: $|\mu |\gtrsim 3{\mu }_N$ in spin-1/2; sign of $\mu$ for $[su][uc]\bar{c}$ in spin-3/2; non-zero $\mathcal{Q}$ (vanishes in $S$-wave molecules); and the $\mathcal{Q}$-$\mathcal{O}$ sign correlation, probing $1/m_q$ weighting.

   hep-phhep-exhep-latJHEP(2026)·2 citations
7. 07*

   Neutrinoless double-beta decay of the ${\Delta }^{-}$ resonance

   Li-Ping He🇨🇳 · Feng-Kun Guo🇨🇳 · Ulf-G. Meißner🇩🇪 · De-Liang Yao🇨🇳 · Xiao-Yu Zhang🇨🇳 · Zhen-Hua Zhang🇨🇳

   The subprocess $nn\to pp{e}^{-}{e}^{-}$ is a key ingredient in the interpretation of nuclear neutrinoless double-beta decay. Intermediate $\Delta$ resonances may provide additional enhancements to this transition. We take a first step toward a $\Delta$-full description of $nn\to pp{e}^{-}{e}^{-}$ by investigating the neutrinoless double-beta decay ${\Delta }^{-}\to p{e}^{-}{e}^{-}$ in the framework of chiral effective field theory. We systematically derive the long-range contribution from light-Majorana-neutrino exchange through loop diagrams and incorporate the short-range part through counterterms required by renormalization. We predict the pion-mass dependence of the decay amplitude in the kinematic configuration with collinear electrons. Furthermore, to facilitate lattice-QCD matching, we calculate the decay amplitude in the degenerate $\Delta$-nucleon mass limit and provide the corresponding long-range prediction.

   hep-phhep-lat0 citations
8. 08*

   Open-flavor threshold effects on quarkonium spectrum in the BOEFT

   Nora Brambilla🇩🇪 · Abhishek Mohapatra🇩🇪 · Tommaso Scirpa🇩🇪 · Antonio Vairo🇩🇪

   The impact of open-flavor thresholds on the quarkonium spectrum has been a subject of study since the introduction of the Cornell potential and has been quantified through various phenomenological approaches, most notably the ${}^3{P}_0$ model. We revisit this problem using the Born--Oppenheimer effective field theory (BOEFT), an effective field theory systematically derived from QCD by exploiting hierarchies of energy scales and symmetries. Within the BOEFT, open-flavor threshold effects emerge from the mixing between quarkonium and tetraquark static potentials sharing the same Born--Oppenheimer quantum numbers. The shapes of the static potentials are constrained by lattice QCD calculations. Furthermore, we account for the distinctive behavior of the BOEFT tetraquark static potentials at short and large distances: at short distances they are repulsive, reflecting the color-octet configuration of the heavy quark-antiquark pair, while at large distances they asymptotically approach heavy-light meson-antimeson thresholds. To quantify threshold effects on the quarkonium spectrum below threshold, we solve a set of coupled Schrödinger equations dictated by the BOEFT, whose only free parameter, the adjoint meson mass, is fixed to the mass of the ${\chi }_{c1}(3872)$ state. These coupled equations are solved both in the spin-isospin averaged threshold limit and, for the first time, including the spin splittings of the physical thresholds. We validate our results by computing the same threshold effects as self-energy corrections to the quarkonium propagator. We compare our predictions with existing experimental data and previous literature. Finally, we provide a field-theoretical interpretation of the pair-creation constant $\gamma$ appearing in the ${}^3{P}_0$ model.

   hep-phhep-exhep-latnucl-th4 citations
9. 09*

   Next-to-next-to-next-to-leading order QCD corrections to photon-pair production

   Michal Czakon🇩🇪 · Felix Eschment🇩🇪 · Terry Generet🇬🇧 · Rene Poncelet🇵🇱

   The production of two isolated photons in high-energy hadron collisions poses a challenge to perturbative QCD because of large corrections through next-to-next-to-leading order (NNLO). We present novel next-to-next-to-next-to-leading order (${\text{N}}^3$LO) predictions and finally demonstrate perturbative convergence for this process. We discuss the considerable computational challenges and phenomenological results for the Large Hadron Collider.

   hep-ph1 citation
10. 10*

    Graviton Production from Inflaton Condensate: Boltzmann vs Bogoliubov

    Chenhuan Wang🇩🇪 · Yong Xu🇨🇦 · Wenbin Zhao🇨🇳

    We study graviton production from an oscillating inflaton condensate during reheating by systematically comparing Boltzmann and Bogoliubov descriptions for inflaton potentials of the form $V(\varphi )\propto {\varphi }^n$ around the minimum. The Bogoliubov framework provides a unified description of graviton production, capturing both perturbative and non-perturbative effects across short and long wavelengths, whereas the Boltzmann approach is restricted to perturbative production at short wavelengths. For the quadratic case ($n=2$), we find that the two approaches yield identical graviton spectra at short wavelengths, indicating that the Boltzmann treatments fully captures perturbative gravitational production in this regime. For steeper potentials ($n>2$), however, we identify a sizable contribution arising from the non-adiabatic transition between inflation and reheating. This component is naturally incorporated in the Bogoliubov formalism but absent in the Boltzmann description, and we show that it is important over a broad range of momenta. We derive analytic approximations within both frameworks that clarify the physical origin and scaling behavior of the spectrum. Our results delineate the regime of validity of Boltzmann approaches and show that, for steeper inflaton potentials, graviton production is governed by non-adiabatic transition dynamics for which the Bogoliubov formalism provides the most appropriate description.

    hep-phastro-ph.COJHEP(2026)·5 citations
11. 11*

    Hydrodynamic Initial Conditions in Small Systems from Proton Phase-Space Entropy

    Gabriel Rabelo-Soares🇧🇷 · Gojko Vujanovic🇨🇦 · Giorgio Torrieri🇧🇷

    The experimental observation of collective behaviour in proton-proton and proton-nucleus collisions poses a fundamental theoretical question regarding the proper characterization of the initial state underlying hydrodynamic evolution. While relativistic hydrodynamics requires an initial condition (IC) characterized by an entropy current, corresponding to a maximally mixed state, the microscopic description of the proton is based on inherently quantum objects, that are projections of pure states. We show that the appropriate matching between proton wave function and classical hydrodynamics emerges from the coarse-graining of its phase-space distribution quantified by the Wehrl-like entropy. This entropy provides a semi-classical, positive-definite measure of the density of accessible microstates at a given resolution scale, and therefore constitutes the appropriate quantity to characterize entropy deposition in small collision systems.

    hep-phnucl-thJ.Subatomic Part.Cosmol.(2026)·0 citations
12. 12*

    Probing muon anomaly and lepton flavor violation with scalar leptoquarks in the 331LHN model

    D. T. Binh🇻🇳 · V. H. Binh🇻🇳 · H. T. Hung🇻🇳 · Duong Van Loi🇻🇳

    We extend the $SU(3{)}_C\times SU(3{)}_L\times U(1{)}_X$ model with neutral leptons (331LHN) by introducing scalar leptoquarks. We determine the particle content of the leptoquark multiplets and their Yukawa interactions with fermions. We find that a singlet leptoquark can fully account for the $4.2\sigma$ discrepancy in the muon anomalous magnetic moment $\Delta a_{\mu }^{2021}$. The corresponding leptoquark mass is constrained to be $m_S\gtrsim 1.8$~TeV, consistent with current LHC bounds. We further consider the updated $\Delta a_{\mu }^{2025}$ based on recent lattice QCD results, which strengthen the lower bound to $m_S\gtrsim 6$~TeV. Combining $\Delta a_{\mu }$ with low-energy leptonic observables, including charged lepton flavor violation and the $\mu$--$e$ conversion rate, we constrain the viable parameter space. The allowed leptoquark Yukawa couplings exhibit a normal hierarchical pattern under all constraints. We also investigate the collider phenomenology of the singlet leptoquark, showing that its QCD-driven pair production leads to suppressed signal rates at the LHC for multi-TeV masses, while future hadron colliders can significantly extend the discovery reach.

    hep-ph0 citations
13. 13*

    Operator Identification in Charged Lepton-Flavor Violation: Global EFT Analysis with RG Evolution, Polarization Observables, and Bayesian Model Discrimination at Future Colliders

    Nicolás Viaux M🇨🇱

    Charged lepton-flavor violation is a null-test frontier of the Standard Model and a direct probe of physics beyond it. We present a global effective field theory (EFT) analysis across FCC-ee, ILC, CLIC, HL-LHC, HE-LHC, and muon colliders at 3 and 10 TeV, with operator identification as the primary target rather than exclusion reach alone. The analysis combines low-energy constraints, collider differential observables, and Dalitz-level $\mu \to 3e$ information in a common profile-likelihood framework. Key hadron-collider and muon-collider signal/background samples are generated at event level and propagated through Delphes detector simulation, while clean $e^{+}{e}^{-}$ benchmark channels are modeled with CDR-calibrated parametric response. We include one-loop renormalization-group (RG) running and operator mixing between UV matching and measurement scales, finding 10--30\% shifts in selected operator-correlation entries when comparing tree-level and RG-evolved coefficient mappings at multi-TeV matching scales. Polarization asymmetries are used to separate $c_{H\ell }$ and $c_{He}$ directions, and UV discrimination is quantified with Bayes factors for benchmark leptoquark and heavy-neutral-lepton hypotheses. The full code chain for event generation, detector response, inference, and figure reproduction is provided.

    hep-phPRD(2026)·0 citations
14. 14*

    Mass creation by the strong interaction: Glueballs -- status and perspectives

    Ulrich Wiedner🇩🇪

    Glueballs represent a fascinating aspect of the strong interaction in nature. Gluons that serve as the mediators of the strong interaction are massless particles, but they possess a property unique to the strong interaction called color charge, which is analogous to electric charge in the electromagnetic interaction. Glueballs are composed of multiple gluons and would be massless without color charges. The interaction of the color charges, however, makes glueballs becoming massive objects. Glueballs thus offer a unique way to study the mass creation of strongly interacting particles.

    hep-phhep-exJ.Subatomic Part.Cosmol.(2026)·0 citations
15. 15*

    Z Boson Radiative Decay $Z\to {\mu }^{+}{\mu }^{-}\gamma$ at the LHC

    Yifan Fei🇨🇳 · Peiran Li🇺🇸 · Zhen Liu🇺🇸 · Maxim Pospelov🇺🇸

    We study the radiative decay of the $Z$ boson, $Z\to {\mu }^{+}{\mu }^{-}\gamma$, at the LHC, providing both Standard Model (SM) precision analysis and new physics projections. With detailed analysis of Run-2 and future HL-LHC performances, we demonstrate that this decay mode can be measured with a statistical precision at the sub-percentage level. From existing Run-1 data, we extract ${\text{Br}}^{\text{fid}}(Z\to \mu \mu \gamma )=(3.34\pm 0.016)\times 10^{-4}$. We further explore the sensitivity of this channel to axion-like particles (ALPs) and to an anomalous $U(1{)}_X$ gauge boson coupled to the muon. Both scenarios feature resonant structures in the dimuon invariant mass spectrum within the $Z\to a/X+\gamma \to {\mu }^{+}{\mu }^{-}\gamma$ final state. Our results show that the radiative $Z$ decay provides a clean and statistically powerful probe of such leptophilic new physics, extending the current collider reach for ALPs and anomalous gauge forces down to $g_X\sim \mathcal{O}(10^{-3})$. This study highlights the potential of rare electroweak gauge boson decays as precision tests of the SM and sensitive probes of new interactions at the LHC.

    hep-phhep-ex0 citations
16. 16*

    Proton Structure from Neural Simulation-Based Inference at the LHC

    Ricardo Barrué🇦🇹 · Lisa Benato🇦🇹 · Ali Kaan Güven🇦🇹 · Elie Hammou🇳🇱 · Jaco ter Hoeve🇬🇧 · Claudius Krause🇦🇹 · Ang Li🇦🇹 · Luca Mantani🇪🇸 · Juan Rojo🇳🇱 · Sergio Sánchez Cruz🇨🇭 · Robert Schöfbeck🇦🇹 · Maria Ubiali🇬🇧 · Daohan Wang🇦🇹

    The precise determination of the parton distribution functions (PDFs) of the proton is an essential ingredient for LHC analyses, including for those at the upcoming High-Luminosity LHC. So far, PDFs are determined from global fits to binned low-dimensional data obtained from unfolded hard-scattering cross section measurements. In this work we demonstrate for the first time the feasibility of neural simulation-based inference (NSBI) for constraining the proton PDFs using a high-dimensional unbinned data set. Exploiting the full statistical power of unbinned data removes the loss of information inherited by the binning procedure. As a proof-of-concept, we determine the gluon PDF from simulated data of top quark pair production at the LHC with $\sqrt{s}=13$ TeV. Taking into account both experimental and theoretical systematic uncertainties in the detector-level features, we demonstrate how the NSBI pipeline achieves significant improvements in precision compared to existing low-dimensional binned analyses. Our results illustrate the potential of unbinned inference to reduce the reliance on coarse approximations of uncertainties and their correlations entering PDF determinations, hence contributing to a new paradigm of unbinned detector-level ML-assisted measurements at the LHC.

    hep-phhep-exnucl-exnucl-th3 citations
17. 17*

    $N$-Jettiness Soft Functions Made Simple

    Luca Buonocore🇨🇭 · Maximilian Delto🇨🇭 · Kirill Melnikov🇩🇪 · Pier Francesco Monni🇨🇭 · Andrey Pikelner🇬🇧 · Gherardo Vita🇨🇭

    We present a new method to compute the soft function for the $N$-Jettiness variable for arbitrary $N$ at high perturbative orders in QCD. It is based on the observation that the most singular part of the soft function, the dipole contribution, can be represented by a sum of an analytically calculable inclusive soft function and a remainder. The latter is absent at NLO, is immediately finite at NNLO and can be made finite with the help of simple NLO-like infrared subtractions at N${}^3$LO. As a byproduct of this approach, we derive a very simple formula for the tripole contribution to the $N$-Jettiness NNLO soft function, which results in a fast numerical evaluation. We apply this method to compute the $N$-Jettiness soft function at NNLO, and report numerical results for up to five jets for the hadron-collider soft function. We finally outline the prospects for applications at N${}^3$LO.

    hep-phJHEP(2026)·2 citations
18. 18*

    On the effective restoration of $U(1{)}_A$ symmetry at finite temperature

    Gert Aarts🇬🇧 · Chris Allton🇬🇧 · Ryan Bignell🇮🇪 · Benjamin Jäger🇩🇰 · Seyong Kim🇰🇷 · Jon-Ivar Skullerud🇮🇪 · Antonio Smecca🇬🇧

    The $U(1{)}_A$ symmetry of the massless QCD Lagrangian is explicitly broken by the axial anomaly, but it may be effectively restored at finite temperature. Determining the temperature at which this occurs is important for understanding the chiral transition and the structure of the QCD phase diagram. A commonly used probe of effective $U(1{)}_A$ restoration is the degeneracy of flavour non-singlet pseudoscalar and scalar susceptibilities. Using anisotropic lattice QCD ensembles with Wilson-clover fermions generated by the \textsc{Fastsum} collaboration, we study this degeneracy through hadronic correlation functions over a wide range of temperatures. The fine temporal resolution of our Generation 3 ensembles allows us to determine the temperature at which the pseudoscalar and scalar channels become degenerate. We find evidence for the effective restoration of $U(1{)}_A$ symmetry at $T_{U(1{)}_A}=319(22)$ MeV, well above the chiral crossover temperature.

    ↳ hep-lathep-ph3 citations
19. 19*

    Asymptotic Theorems and Averaging in Scalar Field Cosmology

    Genly Leon🇨🇱 · Aleksander Kozak🇨🇱 · Claudio Michea🇨🇱

    We present a hybrid study that combines a concise review of scalar-field cosmology with new analytic developments that integrate averaging reductions for oscillatory regimes with dynamical-systems techniques. For oscillatory fields, we derive an averaging reduction that yields an effective slow system whose time averages control dissipation; introducing uniform derivative bounds, Barbalat/LaSalle arguments, and a finite-dimensional center/stable manifold reduction, we carry out late-time analysis of the models. We prove persistence of equilibria, decay estimates, and local invariant manifolds under small $C^k$ perturbations of $\chi (\varphi )$ and $G(a)$, quantify how averaged dissipation lifts to the full oscillatory dynamics with an $\mathcal{O}(H)$ error, and provide numerical examples. In addition to asymptotic reductions, we obtain exact quadrature solutions in general relativistic, anisotropic, and brane-world settings, yielding closed-form expressions for $t(a)$, $\varphi (a)$, and $H(a)$ and enabling analytic computation of inflationary observables.

    ↳ gr-qchep-phmath-phmath.MPJCAP(2026)·0 citations
20. 20*

    From Vacuum to Nucleon: Fixed-$j$ Kernel Matching of Holographic Current Correlators to QCD

    Kiminad A. Mamo🇺🇸

    We show that the normalized non-normalizable photon profile fixed by the vacuum vector-current two-point function, when inserted into the fixed-$j$ hadronic Witten diagram, produces the fixed-$j$ conformal hard kernel in the leading-twist singlet vector channel of deeply virtual Compton scattering (DVCS) and double deeply virtual Compton scattering (DDVCS). For the near-boundary Brower--Polchinski--Strassler--Tan closed-string upper vertex, the Witten diagram yields the Gauss-hypergeometric Wilson-kernel family of the QCD conformal OPE, with the Mellin exponent derived from the explicit $z$-power count ${\delta }_c(j)=j+{\Delta }_c(j)-2$, not inserted as an ansatz. The lower Witten vertex is matched to, or provides a holographic representation of, the nonperturbative conformal moment; it is not a new hard kernel or a freely adjustable skewness profile. The matching is TT-projected, kernel-level, and fixed-scale in the conformal partial-wave/CS representation: finite coefficient normalizations, spin-$j$ source normalizations, scale factors, and lower hadronic matrix elements remain matched inputs. Together with the Nishio--Watari open branch and the protected/unprotected $j=2$ split, this structurally identifies the protected closed branch with the $(-)$ conformal partial wave and the even open branch with the unprotected $(+)$ counterpart in the projected fixed-$j$ singlet vector amplitude; these are mixed singlet eigenchannels, not literal unmixed quark/gluon operators at finite $N_c$. The conformal/Gegenbauer basis used in generalized parton distribution (GPD) deconvolution therefore has a second ultraviolet origin: it is selected both by the QCD OPE and by the near-boundary AdS Witten vertex.

    ↳ hep-thhep-ph2 citations
21. 21*

    Holographic Open/Closed Exchange in Double Deeply Virtual Compton Scattering: Fixed-$j$ Structural Matching to the $\pm$-Basis Wilson Kernels

    Kiminad A. Mamo🇺🇸

    We show that fixed--$j$ holographic double deeply virtual Compton scattering (DDVCS), and its DVCS limit, give a fixed-scale structural match to the singlet conformal-OPE Wilson-kernel family of QCD in the leading-twist unpolarized singlet vector channel. The open-string $C_1(\delta ,\vartheta )$ hypergeometric kernel was derived by Nishio--Watari; the new closed-string result is that the BPST upper Witten vertex gives the same family with a different near-boundary power count, because ${\Delta }_c(j)$ is fixed by the BPST trajectory rather than by open-Regge data. The Mellin exponent is therefore derived as ${\delta }_c(j)=j+{\Delta }_c(j)-2=2j+{\gamma }_c(j)$ rather than inserted by hand. The even open branch gives the parallel unprotected counterpart in the projected singlet vector amplitude. At $Q=\mu ={\mu }_0={\mu }_{\ast }$, the point is not merely that equal-endpoint evolution is trivial; it is that the ultraviolet Witten vertex has already produced the fixed--$j$ conformal kernel before the lower conformal moment is matched. In the conformal partial-wave/CS representation, beta-proportional conformal-anomaly terms and scheme transformations are coefficient/evolution bookkeeping away from the matching point, not replacements for the projected fixed-scale hypergeometric $\eta /\xi$ Wilson-kernel family. The protected/unprotected $j=2$ split identifies the protected closed branch with the $(-)$ conformal partial wave and the even open branch with the unprotected $(+)$ counterpart; these are mixed singlet eigenchannels, not literal unmixed quark/gluon operators at finite $N_c$. Thus, once the lower Witten vertex is matched to constrained conformal moments, the DVCS/DDVCS deconvolution problem is organized in a physical operator basis rather than in arbitrary $x$-space profiles.

    ↳ hep-thhep-ph2 citations
22. 22*

    Probing Collapsed Dark Matter Halos with Fast Radio Bursts

    Yuxuan He🇨🇳 · Weiyang Wang · Chen Zhang🇨🇳 · Yi-Ming Zhong🇨🇳

    Observations of ultra-dense substructures in strong lensing systems challenge the standard cosmological model at small scales. Self-interacting dark matter (SIDM), as an alternative to the cold and collisionless dark matter (CDM) of the standard cosmological model, provides a natural mechanism for forming such structures via gravothermal core collapse. We show that strong gravitational lensing of fast radio bursts (FRBs) provides an effective approach to detecting these substructures and probing dark matter self-interactions. Core-collapsed SIDM halos exhibit steeper central density profiles than CDM halos, enhancing the lensing cross section and producing longer time delays between FRB images. We compute lensing properties of core-collapsed subhalos and host halos, including maximal impact parameters and time-delay distributions. We demonstrate that future all-sky monitors, such as BURSTT, SKA2-Low, and SKA2-Mid, which are expected to detect $10^5$--$10^7$ FRBs over a decade, can measure time-delay distributions with high statistical significance. Modeling collapsed halos with a cored power-law density profile with inner slope $\gamma =3$ and assuming no excess beyond the singular isothermal sphere lens model, we show that our strategy can probe self-interaction cross section strengths of ${\sigma }_{\text{SI}}/m\gtrsim \min \{18,40{\lambda }_{\text{sub}}\}{\text{cm}}^2/\text{g}$, where ${\lambda }_{\text{sub}}$ parameterizes the collapse time of a subhalo relative to that of the isolated case.

    ↳ astro-ph.COastro-ph.HEhep-ph1 citation
23. 23*

    Cross-Domain Transfer with Particle Physics Foundation Models: From Jets to Neutrino Interactions

    Gregor Krzmanc🇺🇸 · Vinicius Mikuni🇯🇵 · Benjamin Nachman🇺🇸 · Callum Wilkinson🇺🇸

    Future AI-based studies in particle physics will likely start from a foundation model to accelerate training and enhance sensitivity. As a step toward a general-purpose foundation model for particle physics, we investigate whether the OmniLearned and ParticleViT foundation models pretrained on diverse high-$Q^2$ simulated and real $pp$ and $ep$ collisions retain useful knowledge to a few-GeV fixed-target neutrino experiment. We process MINERvA neutrino--nucleus scattering events and evaluate pretrained models on two types of tasks: regression of available energy and binary classification of charged-current pion final states ($CC1{\pi }^{\pm }$, $\mathrm{CCN}{\pi }^{\pm }$, and $CC1{\pi }^0$). Pretrained OmniLearned and ParticleViT models outperform similarly sized models trained from scratch at the same compute budget, with the largest gains for OmniLearned on regression and for ParticleViT on classification. When the same transformer architecture is instead initialized from unrelated text pretraining (BERT), this advantage appears only marginally for classification in terms of compute efficiency and not in any way for regression. These results suggest that particle-level foundation models acquire inductive biases that generalize across large differences in energy scale, detector technology, and underlying physics processes, pointing toward detector-agnostic inference in particle physics.

    ↳ hep-excs.LGhep-phphysics.data-an3 citations
24. 24*

    Acoustic instability at shock-wave precursors

    Antonio Capanema🇮🇹 · Pasquale Blasi🇮🇹 · Emanuele Sobacchi

    Magnetic field amplification is an integral part of the process of particle acceleration at non-relativistic shocks. It is necessary to reach the maximum energies required by observations, especially in supernova remnants, thought to be sources of the bulk of Galactic cosmic rays. Such amplification can be caused by the acoustic instability that develops when small density perturbations interact with the cosmic-ray pressure gradient in the upstream of a cosmic-ray-modified shock. The vorticity induced by the nonlinear development of the instability may lead to turbulence, which amplifies the pre-existing magnetic fields. To study this phenomenon, we use the PLUTO code to carry out 2D (and some 3D) magnetohydrodynamical simulations of the evolution of small density perturbations in the presence of an assigned cosmic-ray pressure gradient. Adopting more realistic values of Mach number and cosmic-ray acceleration efficiency than previously assumed in the literature, we show that the acoustic instability can transform small density perturbations into large nonlinear structures while the fluid crosses the precursor region of a cosmic-ray-modified shock. We study the power spectrum of turbulent magnetic fluctuations that may be important to scatter particles. We comment on the possible constructive interference between acoustic and non-resonant streaming instabilities. We discuss limitations of previous and current numerical investigations in accessing spatial scales where turbulence is expected to turn nonlinear, and outline perspectives for future investigations.

    ↳ astro-ph.HEhep-phphysics.plasm-phAstron.Astrophys.(2026)·2 citations
25. 25*

    Primordial Black Holes Formation Beyond the Standard Cosmic QCD Transition

    Maël Gonin🇩🇪 · Oleksii Ivanytskyi🇵🇱 · David Blaschke🇵🇱 · Günther Hasinger🇩🇪

    We review the role of primordial black holes (PBHs) for illuminating the dark ages of the cosmological evolution and as dark matter (DM) candidates. We elucidate the role of phase transitions for primordial black hole formation in the early Universe and focus our attention on the cosmological QCD phase transition within a recent microscopical model. We explore the impact of physics beyond the Standard Model (SM) on the cosmic equation of state and the probability distribution for the formation of PBHs which serve as candidates for DM and contribute to present-day binary black-hole merger events.

    ↳ astro-ph.COhep-phParticles(2026)·6 citations
26. 26*

    Gravitational Gertsenshtein-Zeldovich mechanism for the Association between GW190425 and FRB 20190425A

    Shao-Qin Wu🇨🇳 · Jing-Rui Zhang🇨🇳 · Rong-Gen Cai🇨🇳 · Bing Zhang🇺🇸 · Yun-Long Zhang🇨🇳

    The temporal and spatial coincidence between the gravitational wave (GW) event GW190425 and the fast radio burst (FRB) event FRB 20190425A raises the intriguing possibility of a physical connection between the two. The widely discussed possibility invoking the collapse of a supermassive neutron star as the merger product suffers the inconsistency between the model prediction and the measured inclination angle of the system. Here, we propose a novel physical mechanism to account for the association. We envisage a magnetar located at about 2.5 light hours away from the binary neutron star merger site. The kiloherz GWs generated by the merger are converted into kiloherz electromagnetic (EM) radiation via the Gertsenshtein-Zeldovich (GZ) effect near the magnetar. Subsequent inverse Compton scattering off the kilohertz EM waves by relativistic particles generates the observed gigahertz FRB emission. Our calculation reveals that, with appropriate parameter choices, the properties of FRB 20190425A can be reproduced.

    ↳ astro-ph.HEgr-qchep-ph2 citations
27. 27*

    Defining Absence: The Origin of "Neutrinoless" and How it Obscures the Physics of Matter Creation

    Francesco Vissani🇮🇹

    The term 'neutrinoless' is a cornerstone of modern particle physics, yet it defines a fundamental process by what is missing rather than what is created. We trace the origins of this privative neologism to a 1953 experimental claim and show how a 'sociology of suspicion' transformed Ettore Majorana's affirmative ontology into an agnostic shorthand. By examining this linguistic shift, we argue that our current terminology may obscure the profound physical meaning of the search. Reclaiming the language of 'matter creation' is not merely a semantic choice, but a timely conceptual shift to bridge the gap between experimental caution and the radical character of the laws of nature we aim to uncover.

    ↳ physics.hist-phhep-phnucl-ex1 citation

* 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.