Wed·Feb 21, 2024Wednesday·February 21, 2024

1. 01*

   Coherent $J/\psi$ photoproduction and polarization in peripheral Pb$-$Pb collisions

   Afnan Shatat🇫🇷

   Photonuclear reactions are induced by the strong electromagnetic field generated by ultrarelativistic heavy-ion collisions. These processes have been extensively studied in ultraperipheral collisions, where the impact parameter is larger than twice the nuclear radius. In recent years, the observation of coherent $J/\psi$ photoproduction at very low transverse momentum has been claimed in nucleus$-$nucleus (A$-$A) collisions with nuclear overlap, based on the measurement of an excess in the $J/\psi$ yield with respect to hadroproduction expectations. Such quarkonium measurements can help to constrain the nuclear gluon distribution at low Bjorken-$x$ and high energy. The photoproduced quarkonium is expected to preserve the polarization of the incoming photon due to the $s$-channel helicity conservation. In this contribution, we report on the new preliminary measurements of the $y$-differential cross section and the first polarization analysis of coherently photoproduced $J/\psi$ in peripheral Pb$-$Pb collisions with the ALICE detector at forward rapidity in the dimuon decay channel. Comparison with models will be shown when available.

   nucl-exhep-exEPJ Web Conf.(2024)·2 citations
2. 02*

   Progress of photonuclear cross sections for medical radioisotope production at the SLEGS energy domain

   Xuan Pang · Bao-Hua Sun🇨🇳 · Li-Hua Zhu🇨🇳 · Guang-Hong Lu🇨🇳 · Hong-Bo Zhou · Dong Yang🇨🇳

   Photonuclear reactions using a laser Compton scattering (LCS) gamma source provide a new method for producing radioisotopes for medical applications. Compared with the conventional method, this method has the advantages of a high specific activity and less heat. Initiated by the Shanghai Laser Electron Gamma Source (SLEGS), we conducted a survey of potential photonuclear reactions, $(\text{upgamma},n)$, $(\text{upgamma},p)$, and $(\text{upgamma},{\text{upgamma}}^{\prime })$ whose cross-sections can be measured at SLEGS by summarizing the experimental progress. In general, the data are rare and occasionally inconsistent. Therefore, theoretical calculations are often used to evaluate the production of medical radioisotopes. Subsequently, we verified the model uncertainties of the widely used reaction code TALYS-1.96, using the experimental data of the \ce{^100Mo}$(\text{upgamma},n)$\ce{^99Mo}, \ce{^65Cu}$(\text{upgamma},n)$\ce{^64Cu}, and \ce{^68Zn}$(\text{upgamma},p)$\ce{^67Cu} reactions.

   nucl-exNucl.Sci.Tech.(2023)·6 citations
3. 03*

   A measurement of the sodium and iodine scintillation quenching factors across multiple NaI(Tl) detectors to identify systematics

   D. Cintas🇪🇸 · S. Hedges🇺🇸 · W. G. Thompson🇺🇸 · P. An🇺🇸 · C. Awe🇺🇸 · P. S. Barbeau🇺🇸 · E. Barbosa de Souza🇺🇸 · J. H. Jo🇺🇸 · L. Li🇺🇸 · M. Martínez🇪🇸 · R. H. Maruyama🇺🇸 · G. C. Rich🇺🇸 · R. Runge🇺🇸 · M. L. Sarsa🇪🇸

   The amount of light produced by nuclear recoils in scintillating targets is strongly quenched compared to that produced by electrons. A precise understanding of the quenching factor is particularly interesting for WIMP searches and CE{\nu}NS measurements since both rely on nuclear recoils, whereas energy calibrations are more readily accessible from electron recoils. There is a wide variation among the current measurements of the quenching factor in sodium iodide (NaI) crystals, especially below 10 keV, the energy region of interest for dark matter and CE{\nu}NS studies. A better understanding of the quenching factor in NaI(Tl) is of particular interest for resolving the decades-old puzzle in the field of dark matter between the null results of most WIMP searches and the claim for dark matter detection by the DAMA/LIBRA collaboration. In this work, we measured sodium and iodine quenching factors for five small NaI(Tl) crystals grown with similar thallium concentrations and growth procedures. Unlike previous experiments, multiple crystals were tested, with measurements made in the same experimental setup to control systematic effects. The quenching factors agree in all crystals we investigated, and both sodium and iodine quenching factors are smaller than those reported by DAMA/LIBRA. The dominant systematic effect was due to the electron equivalent energy calibration originating from the non-proportional behavior of the NaI(Tl) light yield at lower energies, potentially the cause for the discrepancies among the previous measurements.

   ↳ hep-exastro-ph.COastro-ph.IMhep-ph+1PRC(2024)·20 citations
4. 04*

   The influence of hadronic rescatterings on the net-baryon number fluctuations

   Qian Chen🇨🇳 · Rui Wen🇨🇳 · Shi Yin🇩🇪 · Wei-jie Fu🇨🇳 · Zi-Wei Lin🇺🇸 · Guo-Liang Ma🇨🇳

   Fluctuations of conserved charges, such as the net-baryon number fluctuations, are influenced by different dynamical evolution processes. In this paper, we investigate the influence of hadronic rescatterings on different orders of cumulants of the net-baryon number distribution. At the start of hadronic rescatterings, we introduce net-baryon number distributions reconstructed based on net-baryon cumulants of different orders obtained from computation in functional renormalization group (FRG), where the distributions were constructed using the maximum entropy method. This way we introduce the critical fluctuations of Quantum Chromodynamics (QCD) into the AMPT model. Firstly, we find that hadronic rescatterings have distinct effects on cumulant ratios of different orders for the net-baryon number. Secondly, we observe that the effect of hadronic rescatterings is more significant for critical fluctuations than dynamical fluctuations, because the two-, three- and four-particle correlation functions due to critical fluctuations are weakened more significantly by hadronic rescatterings.

   ↳ nucl-thhep-phnucl-ex5 citations
5. 05*

   Effects of incompressibility $K_0$ in heavy-ion collisions at intermediate energies

   Xiao-Xiao Long🇨🇳 · Gao-Feng Wei🇨🇳

   Within the possible least uncertainty on the nuclear incompressibility $K_0$, we examine effects of $K_0$ in heavy-ion collisions at intermediate energies. Based on simulations of Au + Au collision at 400 MeV/nucleon using an isospin- and momentum-dependent transport model, we find that the incompressibility $K_0$ indeed affects significantly the attainable density in central regions, and thus the particle productions and/or distributions at final states, e.g., nucleon rapidity distributions and yields of charged pions. Nevertheless, through examining the free neutron over proton ratios $n/p$, the neutron-proton differential transverse and directed flows as well as the charged pion ratio ${\pi }^{-}/{\pi }^{+}$ and its kinetic energy distribution, we find that these observables are less affected by the uncertainty of $K_0$, but mainly sensitive to the slope of symmetry energy at the saturation density. We also compare and discuss our results with the corresponding data.

   ↳ nucl-thnucl-exPRC(2024)·9 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.