Fri·Jun 27, 2025Friday·June 27, 2025

1. 01*

   Measurement of inclusive $J/\psi$ production in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=54.4$ GeV at STAR

   The STAR Collaboration

   This article presents measurements of inclusive $J/\psi$ production at midrapidity ($\left|y\right|<$ 1.0) in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=54.4$ GeV with the STAR detector at the Relativistic Heavy Ion Collider. A suppression of the $J/\psi$ yield, quantified using the nuclear modification factors ($R_{\mathrm{AA}}$, $R_{\mathrm{CP}}$), is observed with respect to the scaled production in $p$+$p$ collisions. The dependence of $R_{\mathrm{AA}}$ on collision centrality and $J/\psi$ transverse momentum is measured with improved precision compared to previous measurements at 39 and 62.4 GeV, while the centrality dependence of $R_{\mathrm{CP}}$ is measured and compared to the same results at 39, 62.4, and 200 GeV. In central collisions, no significant collision energy dependence of $R_{\mathrm{AA}}$ is found within uncertainties for collision energies between 17.3 and 200 GeV. Two transport model calculations that include dissociation and regeneration contributions are consistent with the experimental results within uncertainties. Although no significant collision energy dependence of the $J/\psi$ suppression in high energy heavy-ion collisions up to $\sqrt{s_{\mathrm{NN}}}=200$ GeV is observed within uncertainties, the newly measured results at 54.4 GeV Au+Au collisions provide additional constraints on theoretical calculations of the hot medium evolution and cold nuclear matter effects.

   nucl-exhep-exPLB(2026)·2 citations
2. 02*

   You never have enough J/$\psi$ events: the case for a J/$\psi$ factory

   Stephen Lars Olsen🇰🇷

   In a talk at an IHEP-Beijing symposium celebrating the 50th anniversary of the discovery of the J/$\psi$, I reminisced about some of the interesting phenomena that were observed in J/$\psi$ decays in the BES, BESII, and BESIII detectors during the 35 year long BES experimental program. The three order of magnitude increase in the J/$\psi$ event samples and the improved detector capabilities that occurred during this time led to a persistent series of interesting discoveries and new insights. As more J/$\psi$ events were collected, the scientific interest in them increased and the breadth of physics topics that are addressed by them expanded. In addition, I speculated on what might happen if, in the next few decades, the magnitude of J/$\psi$ data samples and the detector capabilities continued to increase at similar paces. In particular, I emphasize the possibilities of searches for CP violation in strange hyperon decays and testing the CPT~theorem with strangeness-tagged neutral kaon decays.

   ↳ hep-exhep-phnucl-exNPB(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.