Tue·Mar 25, 2025Tuesday·March 25, 2025

1. 01*

   Cross section Measurements for ${}^{12}$C$(K^{-},K^{+}{\Xi }^{-})$ and ${}^{12}$C$(K^{-},K^{+}\Lambda \Lambda )$ Reactions at 1.8 GeV$/c$

   Woo Seung Jung🇰🇷 · Yudai Ichikawa🇯🇵 · Byung Min Kang🇰🇷 · Jung Keun Ahn🇰🇷 · Sung Wook Choi🇰🇷 · Manami Fujita🇯🇵 · Takeshi Harada🇯🇵 · Shoichi Hasegawa🇯🇵 · Shuhei Hayakawa🇯🇵 · Sang Hoon Hwang🇰🇷 · Kenneth Hicks🇺🇸 · Ken'ichi Imai🇯🇵 and 21 other authors

   We present a measurement of the production of ${\Xi }^{-}$ and $\Lambda \Lambda$ in the ${}^{12}$C$(K^{-},K^{+})$ reaction at an incident beam momentum of 1.8 GeV/$c$, based on high-statistics data from J-PARC E42. The cross section for the ${}^{12}$C$(K^{-},K^{+}{\Xi }^{-})$ reaction, compared to the inclusive ${}^{12}$C$(K^{-},K^{+})$ reaction cross section, indicates that the ${\Xi }^{-}$ escaping probability peaks at 70\% in the energy region of $E_{\Xi }=$100 to 150 MeV above the ${\Xi }^{-}$ emission threshold. A classical approach using eikonal approximation shows that the total cross sections for ${\Xi }^{-}$ inelastic scattering ranges between 42 mb and 23 mb in the ${\Xi }^{-}$ momentum range from 0.4 to 0.6 GeV/c. Furthermore, based on the relative cross section for the ${}^{12}$C$(K^{-},K^{+}\Lambda \Lambda )$ reaction, the total cross section for ${\Xi }^{-}p\to \Lambda \Lambda$ is estimated in the same approach to vary between 2.2 mb and 1.0 mb in the momentum range of 0.40 to 0.65 GeV/c. Specifically, a cross section of 1.0 mb in the momentum range of 0.5 to 0.6 GeV/c imposes a constraint on the upper bound of the decay width of the ${\Xi }^{-}$ particle in infinite nuclear matter, revealing ${\Gamma }_{\Xi }<\sim 0.6$ MeV.

   nucl-exhep-phPTEP(2025)·3 citations
2. 02*

   Correlation studies of the ${}^7$He excited states

   M. Khirk (1, 2 and 3) · L.V. Grigorenko (1, 4 and 5)🇷🇺 · E.Yu. Nikolskii (5 and 1)🇷🇺 · P.G. Sharov (1 and 6) ((1) Flerov Laboratory of Nuclear Reactions, JINR, Dubna, (2) M.V. Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow, (3) MIREA - Russian Technological University, Moscow, (4) National Research Nuclear University "MEPhI'', Moscow, (5) National Research Centre "Kurchatov Institute'', Moscow, (6) Institute of Physics, Silesian University in Opava, Opava)

   The unbound nucleus ${}^7$He was recently studied in the ${}^2$H(${}^6$He,${}^1$H)${}^7$He reaction at 29 $A$MeV beam energy in Ref.[M.S. Golovkov et al., Phys. Rev. C 109, L061602 (2024)]. The excitation spectrum of ${}^7$He was measured up to $E_T=8$ MeV ($E_T$ is energy above the ${}^6$He-$n$ threshold). Angular distribution for the ${}^6$He-$n$ decay of the ${}^7$He $3/2^{-}$ ground state can be explained by a strong spin alignment induced by a reaction mechanism. The correlation information for the higher-lying ${}^7$He excitations is available as backward-forward asymmetry for the ${}^6$He-$n$ decay in the ${}^7$He frame. The asymmetry function has an expressed energy profile which may be explained by using quite restrictive assumptions about structure of ${}^7$He excitations or/and peculiarities of the reaction mechanism. In the analysis of [M.S. Golovkov et al., Phys. Rev. C 109, L061602 (2024)] the observation the $s_{1/2}$ state in ${}^7$He is declared with $E_r\approx 2.0$ MeV. Our work is based on the same ${}^7$He data. However, the data analysis was improved and also the data interpretation is substantiated with the detailed PWBA reaction studies and coupled-channel calculations of the ${}^7$He continuous spectrum. The idea of the $s_{1/2}$ resonant state with $E_r\approx 2.0$ is rejected. In addition, the position of the $1/2^{-}$ state in ${}^7$He is confined to the interval $E_r=2.2-3.0$ MeV, with ``preferred'' value 2.6 MeV. There is indication on the second $3/2^{-}$ state in the data with $E_r\sim 4.5$ MeV and with the lower resonance energy limit $E_r\gtrsim 3.5$ MeV. Importance and prospects of more detailed correlation studies of ${}^7$He continuum are discussed.

   nucl-exnucl-th0 citations
3. 03*

   Evidence for J/$\psi$ suppression in incoherent photonuclear production

   ALICE Collaboration

   According to quantum chromodynamics, at sufficiently high energy, the structure of hadrons reveals a dynamic equilibrium between gluon splitting and gluon recombination -- a phenomenon known as saturation. The process of diffractive photonuclear production of a J/$\psi$ vector meson provides a direct insight into the gluon composition of hadrons. The J/$\psi$ production as a function of momentum transferred in the interaction, quantified by the Mandelstam-$t$ variable, serves as an excellent probe for studying the structure of hadrons within the impact-parameter plane, because different ranges in $t$ are sensitive to the dynamics of the gluon field at varying spatial size scales. The ALICE collaboration has measured the energy dependence of incoherent photonuclear production of J/$\psi$ mesons off lead ions, at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV, for three Mandelstam-$t$ intervals. The energy dependence of the photonuclear cross section at the highest $|t|$ range measured, $(0.81<|t|<1.44)$ GeV${}^2$, is sensitive to subnucleonic structures of the Pb target. The increase of the cross section with energy at large $|t|$ shows evidence of suppression with respect to the increase seen at low $|t|$. The observed pattern of the energy evolution in data is similar to that of gluon saturation models.

   nucl-exhep-exPRL(2026)·9 citations
4. 04*

   Measurement of correlations among net-charge, net-proton, and net-kaon multiplicity distributions in Pb$-$Pb collisions at $\sqrt{s_{\text{NN}}}=5.02$ TeV

   ALICE Collaboration

   Correlations among conserved quantum numbers, such as the net-electric charge, the net-baryon, and the net-strangeness in heavy-ion collisions, are crucial for exploring the QCD phase diagram. In this paper, these correlations are investigated using net-proton number (as a proxy for the net-baryon), net-kaon number (for the net-strangeness), and net-charged particle number in Pb--Pb collisions at $\sqrt{s_{\text{NN}}}=5.02$ TeV with the ALICE detector. The observed correlations deviate from the Poissonian baseline, with a more pronounced deviation at LHC energies than at RHIC. Theoretical calculations of the Thermal-FIST hadron resonance gas model, HIJING, and EPOS LHC event generators are compared with experimental results, where a significant impact of resonance decays is observed. Thermal-FIST calculations under the grand canonical and canonical ensembles highlight significant differences, underscoring the role of local charge conservation in explaining the data. Recent lattice QCD studies have demonstrated that the magnetic field generated by spectator protons in heavy-ion collisions affects susceptibility ratios, in particular those related to the net-electric charge and the net-baryon numbers. The experimental findings are in qualitative agreement with the expectations of lattice QCD.

   nucl-exhep-exJHEP(2025)·9 citations
5. 05*

   Charge-dependent nucleon-nucleon interaction at N${}^3$LO in nuclear lattice effective field theory

   Chengxin Wu🇨🇳 · Teng Wang🇨🇳 · Bing-Nan Lu🇨🇳 · Ning Li🇨🇳

   The nuclear lattice effective field theory (NLEFT) is an efficient tool for solving nuclear many-body problems, which takes high-fidelity lattice chiral interactions as input and computes nuclear low-energy observables via quantum Monte Carlo techniques. In this work, we present the first next-to-next-to-next-to-leading order (N${}^3$LO) chiral forces on the lattice with the isospin-breaking effects fully taken into account. We focus on both the charge-independence breaking (CIB) and charge-symmetry breaking (CSB) effects. Specifically, we include the isospin-breaking effect from the mass difference between the charged and neutral pions in the one-pion-exchange potential (OPEP), the Coulomb force for the $pp$ interaction and the contribution of two additional charge-dependent contact operators. We also explicitly incorporate the two-pion-exchange potentials which was mostly neglected in previous NLEFT calculations. With these improvements, we are able to accurately reproduce the $np$ and $pp$ scattering phase shifts up to relative momentum $p\sim 200$ MeV as well as the deuteron properties. The construction of these charge-dependent lattice nuclear forces establishes a solid foundation for future high-precision nuclear ab initio calculations within the NLEFT framework.

   ↳ nucl-thhep-lathep-phnucl-exPRC(2025)·7 citations
6. 06*

   Future Opportunities with Lepton-Hadron Collisions

   Allen Caldwell🇩🇪 · Silvia Dalla Torre🇮🇹 · Rolf Ent🇺🇸 · Aharon Levy🇮🇱 · Paul Newman🇬🇧 · Fred Olness🇺🇸 · Juan Rojo🇳🇱

   Deep Inelastic lepton-hadron Scattering (DIS) is a cornerstone of particle physics discovery and the precision measurement of the structure of matter. This document surveys the international DIS landscape, exploring current and future opportunities to continue this rich heritage, leading to new understandings and enabling discoveries. Of immediate relevance to the future of the field in Europe, the Large Hadron electron Collider (LHeC) offers an impactful bridge between the end of the HL-LHC and the beginning of the next CERN flagship project, both in terms of technology development and new scientific exploration from Higgs physics to the structure of the proton. More generally, the facilities described here cover energies from a few GeV to multiple TeV and address a wide range of topics, with unique sensitivity to Quantum Chromodynamics and hadron structure at their core. Additionally, they enhance the science programmes at hadron-hadron colliders. The fixed-target CEBAF programme at JLab probes nucleon and light ion structure at large x in novel ways, while high energy neutrino DIS is enabled at the FASER and SND@LHC experiments by the intense LHC beams. The Electron Ion Collider (EIC) is on course for deployment at Brookhaven in the early 2030s. Its science includes a 3-dimensional mapping of hadrons, leading to a thorough understanding of the mechanisms behind proton mass and spin. Adding the LHeC provides a Europe-based lepton-hadron frontier, including a complementary Higgs, top and electroweak programme to the HL-LHC, together with precise determinations of proton and nuclear structure in a kinematic range that improves HL-LHC sensitivities. In the longer term, plasma wakefield acceleration and the FCC offer possible major steps forward in centre-of-mass energy, extending into a low parton momentum-fraction domain where new strong interaction discoveries are guaranteed.

   ↳ hep-exhep-phnucl-ex1 citation
7. 07*

   Magneto-$\nu$: Heavy neutral lepton search using ${}^{241}$Pu ${\beta }^{-}$ decays

   C. Lee🇺🇸 · X. Zhang🇺🇸 · A. Kavner🇺🇸 · T. Parsons-Davis🇺🇸 · D. Lee🇺🇸 · N. Hines🇺🇸 · S. T. P. Boyd🇺🇸 · M. Loidl🇫🇷 · X. Mougeot🇫🇷 · M. Rodrigues🇫🇷 · M. K. Lee🇰🇷 · J. Song🇰🇷 and 3 other authors

   The MAGNETO-$\nu$ experiment searches for keV-scale heavy neutral leptons (HNLs) through precise measurements of the ${\beta }^{-}$-decay spectrum of ${}^{241}$Pu. We present spectra comprising a total of 194 million ${\beta }^{-}$ decays recorded using decay energy spectrometry with metallic magnetic calorimeters, representing the most statistically precise measurement of ${}^{241}$Pu ${\beta }^{-}$ decay to date. The $\beta$-endpoint energy was determined using $\gamma$ rays and X rays from an external ${}^{133}$Ba calibration source, yielding $Q_{\beta }=22.273(33)$\,keV. The measured spectrum shows no statistically significant deviation from the allowed $\beta$-decay model. From a subset of the high-statistics data, we set an upper limit on the mixing of an 11.5-keV HNL with the electron neutrino, $|U_{e4}{|}^2<1.31\times 10^{-3}$ at the 95\% confidence level.

   ↳ hep-exnucl-exPRC(2026)·3 citations
8. 08*

   Second order fluctuations of conserved charges in external magnetic fields

   Heng-Tong Ding🇨🇳 · Jin-Biao Gu🇨🇳 · Arpith Kumar🇨🇳 · Sheng-Tai Li🇨🇳

   We present a first-principles lattice QCD investigation of second-order fluctuations of and correlations among conserved charges -- baryon number (B), electric charge (Q), and strangeness (S) -- in the presence of external magnetic fields. Our study employs lattice simulations of (2+1)-flavor QCD with physical pion masses using highly improved staggered fermions (HISQ) on $48^3\times 12$ and $32^3\times 8$ lattices, covering a wide range of magnetic field strengths up to $eB\simeq 0.8$ GeV${}^2$. We identify clear signals of magnetic field-induced modifications to these fluctuations and correlations, with the baryon-electric charge correlation, ${\chi }_{11}^{\mathrm{BQ}}$, exhibiting particularly strong sensitivity to the magnetic field. To bridge theoretical predictions with experimental observables, we implement systematic kinematic cuts that emulate detector acceptances of the STAR and ALICE experiments within the hadron resonance gas (HRG) model and construct proxy observables for fluctuations measurable in heavy-ion collision experiments. Our findings highlight ${\chi }_{11}^{\mathrm{BQ}}$ as a promising ``magnetometer" for probing the presence of magnetic fields in QCD matter. Furthermore, we explore experimentally relevant ratios involving ${\chi }_{11}^{\mathrm{BQ}}$, demonstrating their potential in mitigating volume effects and enhancing sensitivity to magnetic fields in collision environments. Additionally, we assess the limitations of the HRG model at strong magnetic fields, revealing deviations that indicate nontrivial modifications to hadronic degrees of freedom. These results offer new insights into the interplay between thermal and magnetic effects in the QCD phase diagram and provide experimentally relevant guidance for the detection of magnetic fields in heavy-ion collisions.

   ↳ hep-lathep-phnucl-exnucl-thPRD(2025)·20 citations
9. 09*

   Probing Pion Valence Quark Distribution with Beam-charge Asymmetry of Pion-induced $J/\psi$ Production

   Wen-Chen Chang🇹🇼 · Marco Meyer-Conde🇯🇵 · Jen-Chieh Peng🇺🇸 · Stephane Platchkov🇫🇷 · Takahiro Sawada🇯🇵

   We consider the beam-charge asymmetry of the $J/\psi$ production cross sections in ${\pi }^{-}$- versus ${\pi }^{+}$-induced reactions on proton or nuclear targets. We show that the $J/\psi$ production cross section difference between ${\pi }^{-}$ and ${\pi }^{+}$ beams impinging on a proton target has a positive sign with a magnitude proportional to the product of pion's valence quark distribution, $V_{\pi }$, and proton's up and down valence quark distribution difference, $u^V-d^V$. The existing $J/\psi$ production data for ${\pi }^{-}+p$ and ${\pi }^{+}+p$ at 39.5 and 200 GeV/c are consistent with the expected positive beam-charge asymmetry. The magnitude of the asymmetry is compared with calculations performed within two theoretical frameworks, the Color Evaporation Model (CEM) and the Non-Relativistic QCD (NRQCD) formalism. We also examine the beam-charge dependence for pion-induced $J/\psi$ production cross sections measured on the neutron-rich platinum target, and find good agreement between the data and theory for both the negative sign and the magnitude of the beam-charge asymmetry. The comparison between data and theoretical calculations for both proton and platinum targets suggests that the beam-charge asymmetry in pion-induced $J/\psi$ production is a viable method of accessing the valence quark distribution of the pion.

   ↳ hep-phhep-exnucl-exPLB(2025)·1 citation
10. 10*

    Measurement of cosmic muon-induced neutron background with ISMRAN detector in a non-reactor environment

    R.Dey🇮🇳 · P.K.Netrakanti🇮🇳 · D.K.Mishra🇮🇳 · S.P.Behera🇮🇳 · R.Sehgal🇮🇳 · V.Jha🇮🇳 · L.M.Pant🇮🇳

    The Indian Scintillator Matrix for Reactor Anti-Neutrinos (ISMRAN) is an above-ground, very short baseline reactor anti-neutrino (${\overline{\text{ensuremath}\nu }}_e$) experiment, located inside the Dhruva research reactor facility, Mumbai, India. The primary goal of the ISMRAN experiment is the indirect detection of reactor ${\overline{\text{ensuremath}\nu }}_e$ through an inverse beta decay (IBD) process, using a cluster of 90 optically segmented plastic scintillator detectors, weighing $\sim$1 ton. In this work, we present the neutron capture time response and energy deposition of neutron capture signals generated by cosmic muons in the ISMRAN geometry, and we compare these experimental results with Geant4-based Monte Carlo (MC) simulations. The obtained mean capture time of fast neutrons is 74.46 $\pm$ 5.98 $\mu$s and is comparable with the MC simulation results. The efficiency-corrected rate of muon-induced neutron background inside the ISMRAN geometry, due to the presence of a passive shielding structure of 10 cm lead followed by 10 cm borated polyethylene with a surface area of 600 $\mathrm{c}{\mathrm{m}}^2$, deployed on top of the ISMRAN setup, is reported to be 1334 $\pm$ 64 (stat.) $\pm$ 70 (sys.) per day. This result shows good agreement with the expected background rate from MC simulations using Geant4. We also estimate the muon-induced fast-neutron rate in the ISMRAN geometry for the actual shielding configuration of 9000 $\mathrm{c}{\mathrm{m}}^2$ surface area to be 3335 $\pm$ 160 (stat.) $\pm$ 175 (sys.) neutrons $\mathrm{da}{\mathrm{y}}^{-1}$ through an extrapolation, after incorporating the model dependent acceptance correction factor from the Geant4 MC simulation. Finally, using these results, we evaluate the neutron production yield due to the composite shielding in the ISMRAN geometry, which is 2.81$\times$$10^{-5}$ neutrons per $\mu$ per (g/$\mathrm{c}{\mathrm{m}}^2$) at sea level.

    ↳ physics.ins-detnucl-exAstropart.Phys.(2025)·5 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.