Tue·Dec 3, 2024Tuesday·December 3, 2024

1. 01*

   Measurement of $p$-${\Xi }^{-}$ ($\bar{p}$-${\bar{\Xi }}^{+}$) Correlation Function in Isobar and Au+Au Collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV with the STAR Detector

   Boyang Fu (for the STAR Collaboration)🇨🇳

   Understanding the strong interactions between baryons, especially hyperon-nucleon ($Y$-$N$) interactions, is crucial for comprehending the equation-of-state (EoS) of the nuclear matter and inner structure of neutron star. In these proceedings, we present the measurements of $p$-${\Xi }^{-}$ ($\bar{p}$-${\bar{\Xi }}^{+}$) correlation functions with high statistics in Isobar (Ru+Ru, Zr+Zr) and Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV by the STAR experiment. With the Lednický-Lyuboshitz approach, the source size and strong interaction parameters of $p$-${\Xi }^{-}$ ($\bar{p}$-${\bar{\Xi }}^{+}$) pairs are extracted.

   nucl-exhep-exnucl-thEPJ Web Conf.(2025)·3 citations
2. 02*

   Production of Light Nuclei in Au+Au Collisions with the STAR BES-II Program

   Yixuan Jin (for the STAR Collaboration)🇨🇳

   The yields and ratios of light nuclei in heavy-ion collisions offer a method to distinguish between the thermal and coalescence models. Ratios such as ${\mathrm{N}}_{\mathrm{t}}\times {\mathrm{N}}_{\mathrm{p}}/{\mathrm{N}}_{\mathrm{d}}^2$ and ${\mathrm{N}}_{{}^3\mathrm{He}}\times {\mathrm{N}}_{\mathrm{p}}/{\mathrm{N}}_{\mathrm{d}}^2$ are suggested as potential probes to investigate critical phenomena within the QCD phase diagram. The significantly larger datasets from STAR BES-II compared to BES-I, combined with enhanced detector capabilities, allow for more precise measurements. In this proceeding, we present the centrality and energy dependence of transverse momentum spectra and particle yields of (anti-)proton, (anti-)deuteron, and ${}^3\mathrm{He}$ at BES-II energies ($\sqrt{s_{\mathrm{NN}}}$ = $7.7-27$ GeV), as well as the light nuclei to proton yield ratios and coalescence parameters $(B_2(\mathrm{d})$ and $B_3({}^3\mathrm{He}))$.

   nucl-exhep-exnucl-thEPJ Web Conf.(2025)·2 citations
3. 03*

   Directed Flow of $\Lambda$, ${}_{\Lambda }^3\mathrm{H}$ and ${}_{\Lambda }^4\mathrm{H}$ in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 3.2, 3.5, 3.9 and 4.5 GeV at RHIC

   Junyi Han (for STAR Collaboration)🇨🇳

   Studying hyper-nuclei yields and their collectivity can shed light on their production mechanism as well as the hyperon-nucleon interactions. Heavy-ion collisions from the RHIC beam energy scan phase II (BES-II) provide an unique opportunity to understand these at high baryon densities. In these proceedings, we present a systematic study on energy dependence of the directed flow ($v_1$) for $\Lambda$ and hyper-nuclei (${}_{\Lambda }^3\mathrm{H}$, ${}_{\Lambda }^4\mathrm{H}$) from mid-central Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 3.2, 3.5, 3.9 and 4.5 GeV, collected by the STAR experiment with the fixed-target mode during BES-II. The rapidity (y) dependence of the hyper-nuclei $v_1$ is studied in mid-central collisions. The extracted $v_1$ slopes ($\mathrm{d}{v}_1/\mathrm{d}y{|}_{y=0}$) of the hyper-nuclei are positive and decrease gradually as the collision energy increases. These hyper-nuclei results are compared to that of light-nuclei including p, d, t/${}^3\mathrm{He}$ and ${}^4\mathrm{He}$. Finally, these results are compared with a hadronic transport model including coalescence after-burner.

   nucl-exhep-exnucl-thEPJ Web Conf.(2025)·1 citation
4. 04*

   Radiative neutron capture cross section of ${}^{242}$Pu measured at n_TOF-EAR1 in the unresolved resonance region up to 600 keV

   J. Lerendegui-Marco · C. Guerrero · E. Mendoza · J. M. Quesada · K. Eberhardt · A.R. Junghans · V. Alcayne · V. Babiano · O. Aberle · J. Andrzejewski · L. Audouin · V. Becares and 124 other authors

   Accurate neutron capture cross sections are essential for the design and operation of fast reactors using MOX fuels. For ${}^{242}$Pu, the Nuclear Energy Agency (NEA) recommends 8--12% accuracy in the fast energy region (2--500 keV), compared to the current uncertainty of 35%. Moreover, integral experiments and previous measurements suggest the evaluated ${}^{242}$Pu(n,$\gamma$) cross section is overestimated, particularly in the JEFF-3.3 library, which shows a 14% overestimation between 1 keV and 1 MeV. Recent measurements from LANSCE reported a 20--30% reduction in the 1--40 keV range relative to evaluations. To solve these discrepancies, the ${}^{242}$Pu(n,$\gamma$) cross section was measured from 1 to 600 keV at CERN n_TOF-EAR1 facility using a 95(4) mg ${}^{242}$Pu target, enriched to 99.959%. Gamma rays from neutron capture were detected with an array of C${}_6$D${}_6$ scintillators and a novel application of the Pulse Height Weighting Technique was employed. The resulting cross section presents a systematic uncertainty between 8 and 12%, reducing the current uncertainties of 35\% and achieving the accuracy requested by the NEA. Analysis using FITACS produced average resonance parameters, consistent with the analysis of the resolved resonance region. Our data align well with Wisshak and Kaeppeler, and are 10--14\% lower than JEFF-3.3 in the 1--250 keV range, helping to achieve consistency with integral benchmarks. At higher energies, our results are in reasonable agreement with ENDF/B-VIII.1 and JEFF-3.3. In contrast, DANCE results appear to underestimate the cross section by a factor of 2--3 above a few keV.

   nucl-exEPJA(2026)·1 citation
5. 05*

   Heavy-flavor production and hadronization at the LHC: experimental status and perspectives from LHC experiments

   Victor Feuillard (for the ALICE Collaboration)🇩🇪

   Heavy-flavor hadrons are one of the most prominent probes to study the quark-gluon plasma and to test models based on Quantum Chromodynamics (QCD). This contribution presents the latest results regarding heavy-flavor production in ALICE, ATLAS, CMS and LHCb.

   nucl-exPoS(2025)·0 citations
6. 06*

   Uncertainty propagation and covariance analysis of 181Ta(n,{\gamma})182Ta nuclear reaction

   Namrata Singh · Mahesh Choudhary · A. Gandhi · Aman Sharma · Mahima Upadhyay · Punit Dubey · Akash Hingu · G. Mishra · Sukanya De · A. Mitra · L. S. Danu · Ajay Kumar🇨🇦 and 4 other authors

   The neutron capture cross-section for the ${}^{181}$Ta(n,$\gamma$)${}^{182}$Ta reaction has been experimentally measured at the neutron energies 0.53 and 1.05 MeV using off-line $\gamma$-ray spectrometry. ${}^{115}$In(n,n'$\gamma$)${}^{115m}$In is used as a reference monitor reaction cross-section. The neutron was produced via the ${}^7$Li(p,n)${}^7$Be reaction. The present study measures the cross-sections with their uncertainties and correlation matrix. The self-attenuation process, $\gamma$-ray correction factor, and low background neutron energy contribution have been calculated. The measured neutron spectrum averaged cross-sections of ${}^{181}$Ta(n,$\gamma$)${}^{182}$Ta are discussed and compared with the existing data from the EXFOR database and also with the ENDF/B-VIII.0, TENDL-2019, JENDL-5, JEFF-3.3 evaluated data libraries.

   nucl-ex0 citations
7. 07*

   Enhanced production of 60Fe in massive stars

   A. Spyrou🇺🇸 · D. Richman · A. Couture🇺🇸 · C. E. Fields🇺🇸 · S. N. Liddick🇺🇸 · K. Childers · B. P. Crider · P. A. DeYoung · A.C. Dombos · P. Gastis · M. Guttormsen🇳🇴 · K. Hermansen🇺🇸 and 14 other authors

   Massive stars are a major source of chemical elements in the cosmos, ejecting freshly produced nuclei through winds and core-collapse supernova explosions into the interstellar medium. Among the material ejected, long lived radioisotopes, such as 60Fe (iron) and 26Al (aluminum), offer unique signs of active nucleosynthesis in our galaxy. There is a long-standing discrepancy between the observed 60Fe/26Al ratio by {\gamma}-ray telescopes and predictions from supernova models. This discrepancy has been attributed to uncertainties in the nuclear reaction networks producing 60Fe, and one reaction in particular, the neutron-capture on 59Fe. Here we present experimental results that provide a strong constraint on this reaction. We use these results to show that the production of 60Fe in massive stars is higher than previously thought, further increasing the discrepancy between observed and predicted 60Fe/26Al ratios. The persisting discrepancy can therefore not be attributed to nuclear uncertainties, and points to issues in massive-star models.

   nucl-exastro-ph.HENature Communications ( 2024) 15:9608·8 citations
8. 08*

   The Highly-Granular Time-of-Flight Neutron Detector for the BM@N experiment

   S. Morozov🇷🇺 · V. Bocharnikov🇷🇺 · D. Finogeev🇷🇺 · M. Golubeva🇷🇺 · F. Guber🇷🇺 · A. Izvestnyy🇷🇺 · N. Karpushkin🇷🇺 · A. Makhnev🇷🇺 · P. Parfenov🇷🇺 · D. Serebryakov🇷🇺 · A. Shabanov🇷🇺 · V. Volkov🇷🇺 · A. Zubankov🇷🇺

   A new Highly-Granular time-of-flight Neutron Detector (HGND) is being developed and constructed to measure azimuthal neutron flow and neutron yields in nucleus-nucleus interactions in heavy-ion collisions with energies up to 4A GeV in the fixed target experiment BM@N at JINR. Details of the detector design and results of performance studies for neutron identification and reconstruction are shown. Comparison of simulations for different options of the HGND layout at the BM@N is presented. Several proposed methods of neutron reconstruction including machine learning and cluster methods are discussed.

   ↳ hep-exnucl-exNucl.Instrum.Meth.A(2025)·2 citations
9. 09*

   Recent results from STAR for parton distribution functions at low and high $x$ in proton-proton collisions

   Zilong Chang (for the STAR collaboration)🇺🇸

   According to perturbative quantum chromodynamic calculations, in $pp$ collisions at $\sqrt{s}=$~200 and 510 GeV studied at RHIC, jet production in mid-pseudorapidity, $|\eta |<$ 1, is dominated by quark-gluon and gluon-gluon scattering processes. Therefore jets at RHIC are direct probes of the gluon parton distribution functions (PDFs) for momentum fractions 0.01 $<x<$ 0.5. Moreover, $W$ boson cross section ratio, $\sigma (W^{+})/\sigma (W^{-})$, in $pp$ collisions at $\sqrt{s}=510$~GeV, is an effective tool to explore anti-quark PDFs, $\bar{d}/\bar{u}$. Last but not least, di-${\pi }^0$ correlation in forward pseudorapidity, $2.6<\eta <4.0$, is an important indication of the non-linear gluon dynamics at low $x$ where the gluon density is high in protons and nuclei. In this proceeding, we present recent STAR results of mid-pseudorapidity inclusive jet cross-sections at $\sqrt{s}=$~200 and 510 GeV in $pp$ collisions, $W$ boson cross-section ratios at $\sqrt{s}=510$~GeV in $pp$ collisions, and forward di-${\pi }^0$ correlations in $pp$, $p\text{Al}$ and $p\text{Au}$ collisions at $\sqrt{s_{\text{NN}}}=200$~GeV.

   ↳ hep-exnucl-exActa Phys.Polon.Supp.(2025)·0 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.