Fri·Oct 31, 2025Friday·October 31, 2025

1. 01*

   Characterizing the initial state and dynamical evolution in XeXe and PbPb collisions using multiparticle cumulants

   CMS Collaboration

   For the first time, correlations among mixed-order moments of two or three flow harmonics$-$($v_n^k,v_m^l$) and ($v_n^k,v_m^l,v_p^q$), with $k$, $l$, and $q$ denoting the respective orders$-$are measured in xenon-xenon (XeXe) collisions and compared with lead-lead (PbPb) results, providing a novel probe of collective behavior in heavy ion collisions. These measurements compare a nearly spherical, doubly-magic ${}^{208}$Pb nucleus to a triaxially deformed ${}^{129}$Xe nucleus, emphasizing the sensitivity to initial-state geometry fluctuations arising from nuclear deformation. The dependence of these results ($v_n$, $n$ = 2, 3, 4) on the shape and size of the nuclear overlap region is studied. Comparisons between $v_2$, $v_3$, and $v_4$ demonstrate the importance of $v_3$ and $v_4$ in exploring the nonlinear hydrodynamic response of the quark-gluon plasma (QGP) to the initial spatial anisotropy. The results constrain initial-state model parameters that influence the evolution of the QGP. The CMS detector was used to collect XeXe and PbPb data at nucleon-nucleon center-of-mass energies of $\sqrt{s_{\mathrm{NN}}}$ = 5.44 and 5.36 TeV, respectively. Correlations are extracted using multiparticle mixed-harmonic cumulants (up to eight-particle cumulants) with charged particles in the pseudorapidity range $|\eta |$ $<$ 2.4 and transverse momentum range 0.5 $<$ $p_{\mathrm{T}}$ $<$ 3 GeV/$c$.

   nucl-exhep-exPLB(2026)·3 citations
2. 02*

   Enhanced production of charged over neutral kaons in Ar+Sc collisions measured by NA61/SHINE at CERN SPS

   Tomasz Matulewicz🇵🇱

   The isospin symmetry, originating from similar masses of $u$ and $d$ quarks, if exact would result in equal numbers of charged ($K^{+}$ and $K^{-}$) and neutral ($K^0$ and ${\overline{K}}^0$) mesons produced in collisions of isospin-symmetric atomic nuclei. The charged and neutral $K$ meson production in Ar+Sc collisions at a center-of-mass energy of 11.9 GeV per nucleon pair was measured by the NA61/SHINE Collaboration. The production of charged $K$ mesons at mid-rapidity is (18.4$\pm$6.1)\% higher than that of the neutral $K$ mesons.The models of hadron production, including known isospin-symmetry breaking effects, cannot explain the measurements.

   nucl-exEPJ Web Conf.(2026)·0 citations
3. 03*

   One-pion exchange potential in a strong magnetic field

   Daiki Miura🇯🇵 · Masaru Hongo🇯🇵 · Hidetoshi Taya🇯🇵 · Tetsuo Hatsuda🇯🇵

   We derive the one-pion exchange potential (OPEP) in the presence of a homogeneous magnetic field using chiral perturbation theory with nonrelativistic nucleons. Our approach is applicable not only to weak magnetic fields but also to strong ones up to around the pion-mass scale. The Green's function of charged pions is modified by the magnetic field, leading to changes in the nuclear force. By numerically evaluating the modified OPEP incorporating its spin and isospin dependencies, we show that the range of the potential decreases in both directions parallel and perpendicular to the magnetic field as the field strength increases. We also compute the resulting energy shift of the deuteron due to the modified OPEP, which can reach the order of 1 MeV around $|eB|=m_{\pi }^2$, which is comparable to the deuteron binding energy.

   ↳ nucl-thhep-phhep-thnucl-exPTEP(2026)·3 citations
4. 04*

   Robust extraction of power corrections and nuclear dynamics from DIS at large $x$

   Alberto Accardi🇺🇸 · Matteo Cerutti🇫🇷

   We present recent updates from the CTEQ-JLab (CJ) global PDF analysis, focusing on the interplay and implementation systematics of the HT and offshell correction (CJ22ht). We also discuss preliminary results of the CJ25 global analysis, showing the impact of the full JLab 6 GeV datasets, that we recently collected in a comprehensive DIS database, and having a first look at early JLab 12 GeV measurements. We finally offer a few thoughts on how future data may help unraveling the nuclear and partonic dynamics in light nuclei.

   ↳ hep-phhep-exnucl-exPoS(2025)·0 citations
5. 05*

   Automated event generation for S-wave quarkonium and leptonium production in NRQCD and NRQED

   Alice Colpani Serri🇵🇱 · Chris A. Flett🇫🇷 · Jean-Philippe Lansberg🇫🇷 · Olivier Mattelaer🇧🇪 · Hua-Sheng Shao🇫🇷 · Lukas Simon🇫🇷

   We present an extension of the MadGraph5_aMC@NLO framework that enables the automated calculation of leading-order cross sections for S-wave quarkonium and leptonium production within the non-relativistic QCD (NRQCD) and non-relativistic QED (NRQED) factorisation formalisms. The framework has been validated against a variety of benchmark processes, demonstrating robustness and flexibility for phenomenological studies. A key advantage of this implementation is its seamless integration with existing MadGraph5_aMC@NLO features, allowing computations not only within the Standard Model but also in a wide range of Beyond the Standard Model or Effective Field Theory scenarios via a modified Universal Feynman Output (UFO) interface. Furthermore, the framework maintains compatibility with standard Monte Carlo event generators for parton showering and hadronisation. Through numerous examples, we highlight that theoretical studies of quarkonium processes require careful consideration: the impact of subleading contributions is often difficult to predict using simple counting arguments based solely on the hierarchy of couplings and velocity-scaling rules.

   ↳ hep-phhep-exnucl-exnucl-thJHEP(2026)·5 citations
6. 06*

   Determination of the initial condition for the Balitsky-Kovchegov equation with transformers

   Meisen Gao🇨🇳 · Zhong-Bo Kang🇺🇸 · Jani Penttala🇺🇸 · Ding Yu Shao🇨🇳

   In the high-energy limit of QCD, scattering off nucleons and nuclei can be described in terms of Wilson-line correlators whose energy dependence is perturbative. The energy dependence of the two-point correlator, called the dipole amplitude, is governed by the Balitsky-Kovchegov (BK) equation. The initial condition for the BK equation can be fitted to the experimental data, which requires evolving the dipole amplitude for a large set of different parameter values. In this work, we train a transformer model to learn the energy dependence of the dipole amplitude, skipping the time-consuming numerical evaluation of the BK equation. The transformer predicts the learned dipole amplitude and the leading order inclusive deep inelastic scattering cross section very accurately, allowing for efficient fitting of the initial condition to the experimental data. Using this setup, we fit the initial condition of the BK equation to the inclusive deep inelastic scattering data from HERA and consider two different starting points $x_0$ for the evolution. We find better agreement with the experimental data for a smaller $x_0$. This work paves the way for future studies involving global fits of the dipole amplitude at leading order and beyond.

   ↳ hep-phnucl-exnucl-thJHEP(2026)·5 citations
7. 07*

   Baryon-antibaryon photoproduction cross sections off the proton

   GlueX Collaboration: F. Afzal🇩🇪 · M. Albrecht🇺🇸 · M. Amaryan🇺🇸 · S. Arrigo🇺🇸 · V. Arroyave🇺🇸 · A. Asaturyan🇺🇸 · A. Austregesilo🇺🇸 · Z. Baldwin🇺🇸 · F. Barbosa🇺🇸 · J. Barlow🇺🇸 · E. Barriga🇺🇸 · R. Barsotti🇺🇸 and 127 other authors

   The GlueX experiment at Jefferson Lab has observed $p\bar{p}$ and, for the first time, $\Lambda \bar{\Lambda }$ and $p\bar{\Lambda }$ photoproduction from a proton target at photon energies up to 11.6 GeV. The angular distributions are forward peaked for all produced pairs, consistent with Regge-like $t$-channel exchange. Asymmetric wide-angle anti-baryon distributions show the presence of additional processes. In a phenomenological model, we find consistency with a double $t$-channel exchange process where anti-baryons are created only at the middle vertex. The model matches all observed distributions with a small number of free parameters. In the hyperon channels, we observe a clear distinction between photoproduction of the $\Lambda \bar{\Lambda }$ and $p\bar{\Lambda }$ systems but general similarity to the $p\bar{p}$ system. We report both total cross sections and cross sections differential with respect to momentum transfer and the invariant masses of the created particle pairs. No narrow resonant structures were found in these reaction channels. The suppression of $s\bar{s}$ quark pairs relative to $d\bar{d}$ quark pairs is similar to what has been seen in other reactions.

   ↳ hep-exnucl-exnucl-thPRC(2026)·1 citation
8. 08*

   A Unified Model and Optimization for Deep Space Radiation Shielding Based on Proton Density

   Li Zhenchao · Yang Aixiang

   In the field of deep space radiation shielding design, traditional high-Z metals are being progressively replaced by novel low-Z materials such as hydrogenated graphene foam, polyethylene-carbon nanotube composite fibers, and boron-rich hydrogen-containing metal-organic frameworks. This transition stems from the constraints of the "gram-scale weight reduction" bottleneck. However, the mechanisms behind these materials' outstanding "lightweight performance" remain at the purely phenomenological level. To address this issue, this paper innovatively proposes a ternary coupled semi-empirical model, with "proton density" (rho_p) as the core independent variable (equivalent to electron density), establishing correlations with full absorption threshold (Eth) and proton utilization rate (eta_p). To validate the model's practicality in complex system design, we embedded it into the NSGA-II genetic algorithm (POP=20, MAXGEN=10). Under constraints of 2-5 layer structures with total thickness <=1 cm, the model's predicted optimal solutions showed an average design error of only 6.2%-8.2% compared to Geant4 heavy simulation dose results. This study provides the first quantitative physical explanation of the inherent trade-off between low-Z materials' "mass savings" and high-Z materials' "space savings." When rho_p<1 mol cm^-3, materials demonstrate extremely high proton utilization rates (eta_p reaching 60-100 MeV cm^-2 mol^-1), achieving 35%-55% mass savings. Conversely, when rho_p>1 mol cm^-3, although eta_p drops below 30 MeV cm^-2 mol^-1, its exceptionally high full absorption threshold (Eth) enables ultra-thin shielding technology. This work offers a robust, physically interpretable, and scalable design tool for multi-objective optimization of area density, thickness, and dose in deep space missions.

   ↳ astro-ph.IMnucl-exphysics.app-ph0 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.