Tue·Nov 1, 2022Tuesday·November 1, 2022

1. 01*

   System size dependence of particle production and collectivity from the STAR experiment at RHIC

   Tong Liu (1) (for the STAR collaboration, (1) Yale University)🇺🇸

   Medium modification of particle spectra and the origin of collectivity in small collision systems are widely debated topics in the heavy-ion community. To address these open questions, we propose the study of particle production and collectivity for varying system sizes,Au+Au $>$ Ru+Ru/Zr+Zr $>$ Cu+Cu $>$ d+Au $>$ $\gamma$+Au, available at RHIC using the STAR detector. We present the first measurements of centrality dependent charged hadron production in Isobar (Ru+Ru and Zr+Zr) collisions, including the nuclear modification factors ($R_{\mathrm{AA}}$) at high transverse momentom ($p_{\mathrm{T}}$), and identified particle spectra at low $p_{\mathrm{T}}$\ at mid-rapidity. Combined with existing results from other systems, they probe system size and collision geometry dependences of the medium modification to particle production. In addition, we present the measurement of particle production and long-range di-hadron correlations in $\gamma$+Au events using ultra-peripheral Au+Au collisions at RHIC.

   nucl-exActa Phys.Polon.Supp.(2023)·3 citations
2. 02*

   Collective enhancement in nuclear level density of ${}^{72}$Ga and its effect on ${}^{71}$Ga(n, $\gamma$)${}^{72}$Ga capture cross-section

   Rajkumar Santra🇮🇳 · Balaram Dey · Subinit Roy🇮🇳 · R. Palit🇮🇳 · Md. S. R. Laskar🇮🇳 · H. Pai🇷🇴 · S. Rajbanshi · Sajad Ali🇮🇳 · Saikat Bhattacharjee🇨🇦 · F. S. Babra · Anjali Mukherjee🇮🇳 · S. Jadhav🇮🇳 and 3 other authors

   The $\gamma$-gated proton spectra measured in the reactions ${}^{64}$Ni(${}^9$Be, p2n)${}^{70}$Ga and ${}^{64}$Ni(${}^9$Be, pn)${}^{71}$Ga, have been utilized to obtain the nuclear level density (NLD) of ${}^{71}$Ga and ${}^{72}$Ga nuclei by using the statistical model (SM) calculations. It is seen that the $\gamma$-gated proton spectrum are reasonably explained by using the large value of the inverse level density parameter ($k$ = 11.2 MeV) in the NLD prescription of the Fermi gas (FG) model. The large value of $k$ is indicative of the rotational enhancement, which is consistent with the earlier results in other mass regions. Furthermore, a rotational enhancement factor has been included in the NLD and used in the SM calculation keeping the systematic value of $k$=8.6 MeV and it explains the $\gamma$-gated proton spectrum nicely. The result clearly indicates the presence of collective enhancement in NLD. Subsequently, the NLD with collective enhancement has been utilized in the TALYS calculation, for the first time, to calculate the ${}^{71}$Ga(n, $\gamma$)${}^{72}$Ga capture cross-section. It is observed that, while the FG model without the collective enhancement in the NLD for ${}^{72}$Ga under predicts the capture data, with the rotational enhancement correction the FG model over predicts the data by similar amount at higher energies. However, in the energy range of 0.01 MeV to 0.1 MeV, the FG model corrected for rotational enhancement describes the data quite well. Thus, the present work indicates that collective enhancement, whenever required, should be taken into account fro proper description of low energy capture cross section data.

   nucl-ex0 citations
3. 03*

   Correlation of heavy-flavour hadron production and charged-particle multiplicity in pp collisions measured by ALICE

   ALICE Collaboration: Joyful Elma Mdhluli🇿🇦

   Heavy-flavour (HF) quarks, i.e. charm and beauty, are produced in the early stages of ultra-relativistic collisions via hard scattering processes. The measurement of heavy flavour as a function of charged-particle multiplicity not only provides information on how the production mechanisms are influenced by the event activity, but can also be considered as a tool to test the role of multiple parton interactions. Furthermore, charged-particle multiplicity studies are essential for reference measurements, to tune theoretical models and to provide information on the global characteristics of events. In ALICE, charged-particle multiplicity and heavy-flavour production in the hadronic and electronic decay channels are measured at central rapidity while HF-decay muons and $J/\psi \to {\mu }^{+}{\mu }^{-}$ are measured at forward rapidity. In this contribution, results will be presented on relative $J/\psi$, average D-mesons and leptons from HF hadron decay yields as a function of charged-particle multiplicity in proton-proton (pp) collisions at $\sqrt{s}$ = 5.02, 7, 8 and 13 TeV. These results will also be compared to theoretical model calculations.

   ↳ hep-exnucl-exJ.Phys.Conf.Ser.(2023)·0 citations
4. 04*

   Instrumentation for correlated prompt $n$-$\gamma$ emission studies in coincidence with fission fragments

   S. Marin · I. Tolstukhin · M. B. Oberling · R. A. Knaack · B. P. Kay · D. L. Duke · K. B. Montoya · D. Connolly · W. Loveland · A. Chemey · S. A. Pozzi · F. Tovesson

   Recent theoretical and experimental results have brought renewed interest and focus on the topic of fission fragment angular momentum. Measurements of neutrons and $\gamma$ rays in coincidence with fission fragments remain the most valuable tool in the exploration of fission physics. To achieve these scientific goals, we have developed a system that combines a state-of-the-art fission fragment detector and $n$-$\gamma$ radiation detectors. A new twin Frisch-gridded ionization chamber has been designed and constructed for use with a spontaneous fission source and an array of forty \textit{trans}-stilbene organic scintillators (FS-3) at Argonne National Laboratory. The new ionization chamber design we present in this work aims at minimizing particle attenuation in the chamber walls, and provides a compact apparatus that can be fit inside existing experimental systems. The ionization chamber is capable of measuring fission fragment masses and kinetic energies, whereas the FS-3 provides neutron and gamma-ray multiplicities and spectra. The details of both detector assembly are presented along with the first experimental results of this setup. Planned event-by-event analysis and future experiments are briefly discussed.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2023)·2 citations
5. 05*

   Investigation of the neutron imaging applications using fine-grained nuclear emulsion

   Abdul Muneem🇯🇵 · Junya Yoshida🇯🇵 · Hiroyuki Ekawa🇯🇵 · Masahiro Hino🇯🇵 · Katsuya Hirota🇯🇵 · Go Ichikawa🇯🇵 · Ayumi Kasagi🇯🇵 · Masaaki Kitaguchi🇯🇵 · Naoto Muto · Kenji Mishima🇯🇵 · Jameel-Un Nabi🇵🇰 · Manami Nakagawa🇯🇵 · Naotaka Naganawa · Takehiko R. Saito🇯🇵

   Neutron imaging is a non-destructive inspection technique with a wide range of applications. One of the important aspects concerning neutron imaging is achieving micrometer-scale spatial resolution. Developing a neutron detector with a high resolution is a challenging task. Neutron detectors, based on fine-grained nuclear emulsion, may be suitable for high resolution neutron imaging applications. High track density is a necessary requirement to improve the quality of neutron imaging. However, the available track analysis methods are difficult to apply under high track density conditions. Simulated images were used to determine the required track density for neutron imaging. It was concluded that a track density of the order of $10^4$ tracks per 100 $\times$ 100 $\mu$m${}^2$ is sufficient to utilize neutron detectors for imaging applications. The contrast resolution was also investigated for the image data sets with various track densities and neutron transmission rates. Moreover, experiments were performed for neutron imaging of the gadolinium-based gratings with known geometries. The structure of gratings was successfully resolved. The calculated 1$\sigma$ 10-90 \% edge response, using the gray scale optical images of the grating slit with a periodic structure of 9 $\mu$m, was 0.945 $\pm$ 0.004 $\mu$m.

   ↳ physics.ins-detnucl-exJ.Appl.Phys.(2023)·1 citation
6. 06*

   Probing fluctuations and correlations of strangeness by net-kaon cumulants in Au+Au collisions at $\sqrt{s_{NN}}=7.7$ GeV

   Qian Chen🇨🇳 · Han-Sheng Wang🇨🇳 · Guo-Liang Ma🇨🇳

   We calculate the cumulants and correlation functions of net-kaon multiplicity distributions in Au+Au collisions at $\sqrt{s_{NN}}=7.7$ GeV using a multiphase transport model (AMPT) with both a new coalescence mechanism and all charge conservation laws. The AMPT model can qualitatively describe the centrality dependences of the net-kaon cumulants and cumulant ratios measured by the STAR experiment. By focusing on the stage evolution of the cumulants, cumulant ratios, and correlation functions, we reveal several key effects on the fluctuations and correlations of strangeness during the dynamical evolution of relativistic heavy-ion collisions, including strangeness production and diffusion, hadronization, hadronic rescatterings, and weak decays. Without considering the quantum chromodynamics critical fluctuations in the dynamic model, we demonstrate that the net-kaon fluctuations can largely represent the net-strangeness fluctuations. Our results provide a baseline for understanding the net-kaon and net-strangeness fluctuations, which help to search for the possible critical behaviors at the critical end point in relativistic heavy-ion collisions.

   ↳ nucl-thhep-phnucl-exPRC(2023)·6 citations
7. 07*

   Wavefunction matching for solving quantum many-body problems

   Serdar Elhatisari · Lukas Bovermann · Yuanzhuo Ma · Evgeny Epelbaum · Dillon Frame · Fabian Hildenbrand · Myungkuk Kim · Youngman Kim · Hermann Krebs · Timo A. Lähde · Dean Lee · Ning Li and 6 other authors

   Ab initio calculations play an essential role in our fundamental understanding of quantum many-body systems across many subfields, from strongly correlated fermions to quantum chemistry and from atomic and molecular systems to nuclear physics. One of the primary challenges is to perform accurate calculations for systems where the interactions may be complicated and difficult for the chosen computational method to handle. Here we address the problem by introducing a new approach called wavefunction matching. Wavefunction matching transforms the interaction between particles so that the wavefunctions up to some finite range match that of an easily computable interaction. This allows for calculations of systems that would otherwise be impossible due to problems such as Monte Carlo sign cancellations. We apply the method to lattice Monte Carlo simulations of light nuclei, medium-mass nuclei, neutron matter, and nuclear matter. We use high-fidelity chiral effective field theory interactions and find good agreement with empirical data. These results are accompanied by new insights on the nuclear interactions that may help to resolve long-standing challenges in accurately reproducing nuclear binding energies, charge radii, and nuclear matter saturation in ab initio calculations.

   ↳ nucl-thcond-mat.quant-gashep-latnucl-ex+1Nature(2024)·110 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.