Mon·Jan 27, 2025Monday·January 27, 2025

1. 01*

   Study of Nucleon Charge-Exchange Processes at ${}^{12}$C Fragmentation with an Energy of 300 MeV/Nucleon

   A.A. Kulikovskaya · M.A. Martemianov

   The search of reactions with nucleon charge-exchange was performed on the FRAGM fragment-separator of the TWAC accelerator complex at fragmentation of carbon nuclei with an energy of 300 MeV/nucleon on a thin beryllium target. The experimental setup, located at an angle of 3.5 degrees to the incident beam, had high momentum resolution. Differential cross sections were measured for ${}^{11}$Be, ${}^{12}$B and ${}^{12}$Be as function of the nuclei momentum. The experimental data were compared with theoretical predictions of various models of nucleus-nucleus interactions and other experimental results. Measurements of nucleon charge exchange processes in this energy region was carried out for the first time. New results were obtained to test theoretical models of nucleus-nucleus interactions.

   nucl-exPhys.Part.Nucl.(2025)·1 citation
2. 02*

   Longitudinal flow decorrelations in light ion collisions

   Hadi Mehrabpour🇨🇳 · Abhisek Saha🇨🇳

   This study presents a detailed analysis of longitudinal flow decorrelations in light ion collisions at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider(LHC) energies for the first time. We compare different theoretical models of the oxygen structure and find that certain observables, such as the flow vector correlator, can distinguish between them, particularly highlighting differences between the variational Monte Carlo (VMC) structure and other models, such as Nuclear Lattice Effective Field Theory (NLEFT) and the Projected Generator Coordinate Method (PGCM), which behave similarly. We further examine flow decorrelations across different systems, including d+Au and O+O collisions at 200 GeV, as well as Ne+Ne and O+O collisions at 6.37 TeV, indicating a hierarchy in decorrelations that underscores the complexity of these interactions. Our findings emphasize that the role of asymmetry in d+Au collisions and its impact on flow correlations is mitigated using a modified flow correlation defined as a ratio of two flow vector covariances derived from different pairs of pseudorapidity bins. Additionally, our analysis of flow angle decorrelations shows diverse distributions across various systems, finding distinct patterns in d+Au collisions compared to other collision systems.

   ↳ nucl-thhep-phnucl-exEPJC(2025)·6 citations
3. 03*

   QED corrections to the parity-violating asymmetry in high-energy electron-nucleus collisions

   Xavier Roca-Maza🇪🇸 · D H. Jakubassa-Amundsen🇩🇪

   The parity-violating asymmetry, including leading-order QED corrections to the Coulomb potential, is calculated non-perturbatively by solving the Dirac equation. At GeV collision energies and forward scattering angles, QED effects enhance the asymmetry by approximately 5% for the recently measured nuclei 27Al, 48Ca, and 208Pb. The corrections result in a shift of the estimated neutron radius, leading to an increase in the inferred neutron skin thicknesses of these nuclei and, thus, to the pressure neutrons feel around nuclear saturation density.

   ↳ nucl-thnucl-exPRL(2025)·16 citations
4. 04*

   Can one-loop corrections to the one-gluon exchange potential adequately describe the charmed meson spectrum?

   A. Capelo-Astudillo🇪🇨 · T. Aguilar🇪🇨 · M. Conde-Correa🇪🇨 · A. Duenas-Vidal🇪🇨 · P. G. Ortega🇪🇸 · J. Segovia🇪🇸

   We investigate the charmed meson spectrum using a constituent quark model (CQM) with one-loop corrections applied to the one-gluon exchange (OGE) potential. The study aims to understand if the modified version of our CQM sufficiently account for the charmed meson spectrum observed experimentally, without invoking exotic quark and gluon configurations such as hybrid mesons or tetraquarks. Within this model, charmed mesons' masses are computed, comparing theoretical predictions to experimental data. The results, within uncertainties, suggest that our theoretical framework generally reproduces mass splittings and level ordering observed for charmed mesons. Particularly, large discrepancies between theory and experiment found in $P$-wave states are, at least, significantly ameliorated by incorporating higher-order interaction terms. Therefore, the findings emphasize that while the traditional quark model is limited in fully describing charmed mesons, enhanced potential terms may bridge the gap with experimental observations. The study contributes a framework for predicting excited charmed meson states for future experimental validation.

   ↳ hep-phhep-exhep-latnucl-ex+1Symmetry(2025)·2 citations
5. 05*

   Automated NLO calculations for asymmetric hadron-hadron collisions in MadGraph5_aMC@NLO

   Carlo Flore🇮🇹 · Daniel Kikoła🇵🇱 · Aleksander Kusina🇵🇱 · Jean-Philippe Lansberg🇫🇷 · Olivier Mattelaer🇧🇪 · Anton Safronov🇵🇱

   We have extended {\tt MadGraph5\_aMC@NLO} capabilities by implementing computations for asymmetric hadron-hadron collisions, including proton-nucleus, pion-hadron or nucleus-nucleus collisions in order to obtain a tool for automated perturbative computations of cross sections (or ratios of cross sections) in asymmetric reactions at next-to-leading (NLO) order in ${\alpha }_S$ in collinear factorisation. This tool, like the original symmetric version of \texttt{MadGraph5\_aMC@NLO}, automatically computes cross sections for different factorisation and renormalisation scales and PDFs provided by the {\tt LHAPDF} library, thereby allowing for an easy assessment of the associated theoretical uncertainties. In this paper, we present the validation of our code using $W$ and $Z$ boson production in $p$Pb collisions and Drell-Yan-pair production in $\pi W$ collisions. We also illustrate the capabilities of the framework by providing cross section and nuclear modification factors with their uncertainties for the production of $W$ and $Z$ bosons, charm and bottom quarks as well as associated production of $b\bar{b}+H^0$ in $p$Pb collisions at the LHC.

   ↳ hep-phhep-exnucl-exnucl-thEPJA(2025)·4 citations
6. 06*

   Measurement of Radon-222 concentration in N2 using an activated charcoal trap

   N. Fatemighomi🇨🇦 · Y. Ahmed🇨🇦 · S. M. A. Hussain🇨🇦 · J. Lu🇨🇦 · A. Pearson🇨🇦 · J. Suys🇨🇦

   Radon-222 is a limiting background in many leading dark matter and low energy neutrino experiments. One way to mitigate Radon-222 is to fill external experimental components with a clean cover gas such as N2. At the SNOLAB facility in Canada, the 222Rn concentration in the cover gas systems of the experiments are monitored using a radon assay board developed by the SNO collaboration. To improve the sensitivity of N2 assays, a new trapping mechanism based on activated charcoal has been developed. The trap was purified and tested at SNOLAB. The methods for determining the efficiency, background, and sensitivity of the trap were described. Additionally, as part of the efficiency measurement, a radon calibration source was developed and characterized.

   ↳ physics.ins-dethep-exnucl-exNucl.Instrum.Meth.A(2025)·2 citations
7. 07*

   Upgrades and maintenance of the CRYRING@ESR electron cooler for improved internal electron target operation

   Athanasios Koutsostathis (1) · Claude Krantz (2) · Elena-Oana Hanu (2) · Frank Herfurth (2)🇩🇪 · Regina Heß (2)🇩🇪 · Wolfgang Kaufmann (2) · Michael Lestinsky (2)🇩🇪 · Mirko Dieter Looshorn (3,4) · Esther Babette Menz (2)🇩🇪 · Andreas Reiter (2) · Jon Roßbach (2) · Stefan Schippers (3,4) · Phe Man Suherman (2) ((1) Department of Physics, National Technical University of Athens, Greece, (2) GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany, (3) I. Physikalisches Institut, Universität Gießen, Giessen, Germany, (4) Helmholtz Forschungsakademie Hessen für FAIR (HFHF), Campus Gießen, GSI Helmholtzzentrum für Schwerionenforschung, Giessen, Germany)

   The electron cooler of the CRYRING@ESR storage ring at the GSI-FAIR accelerator complex is a unique instrument, which not only provides beam cooling of the stored ions, but also serves as a low-energy electron target for Dielectronic Recombination experiments. The minimisation of vacuum contamination and the response to rapid energy changes are key requirements of the cooler in electron target mode. Therefore, a test bench was prepared to study the outgassing behaviour of the electron gun components and a setup was constructed to evaluate the drift-electrode-modulation of the acceleration voltage of the cooler. The vacuum studies showed that the electron gun cathode was severely malfunctioning and resulted in its replacement. The drift-electrode-modulation of the acceleration voltage showed significant improvements compared to direct modulation of the terminal voltage of the cooler.

   ↳ physics.acc-phnucl-exphysics.atom-phphysics.ins-detAdv.Nucl.Phys.(2025)·2 citations
8. 08*

   Signature of the $\alpha$-clustering structure of Light Nuclei in Relativistic Nuclear Collisions

   Zhiyong Lu🇨🇳 · Mingrui Zhao🇨🇳 · Emil Gorm Dahlbæk Nielsen🇩🇰 · Xiaomei Li🇨🇳 · You Zhou🇩🇰

   The "imaging-by-smashing" technique has been developed recently in relativistic nuclear collisions. By smashing heavy nuclei at RHIC and the LHC and analyzing the anisotropic expansion (flow) of the final state produced particles, unique information on the structure of the collided nuclei has been obtained. Existing efforts primarily focus on the colliding mode of heavy nuclei collisions. In contrast, nuclear structure studies with collisions of light nuclei and the fixed target mode, despite their significant impact and broad interest, have not been thoroughly explored. In this Letter, we investigate the $\alpha$-clustering signature of ${}^{20}$Ne and ${}^{16}$O in the fixed-target ${}^{208}$Pb--${}^{20}$Ne and ${}^{208}$Pb--${}^{16}$O collisions at $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 68.5 GeV, using the parton transport model AMPT. The results of two- and four-particle cumulants of anisotropic flow demonstrate a robust $\alpha$-clustering signature that persists regardless of the complex dynamic evolution of the created systems. This study highlights the significant impact of the LHCb SMOG (SMOG2) project in discovering the $\alpha$-clustering signature of light nuclei at relativistic energies.

   ↳ nucl-thnucl-exPLB(2025)·12 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.