Tue·Jun 1, 2021Tuesday·June 1, 2021

1. 01*

   Probing dense QCD matter: Muon measurements with the CBM experiment at FAIR

   Anna Senger🇩🇪 · Peter Senger (for the CBM Collaboration)🇩🇪

   The Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt is designed to investigate the properties of high-density QCD matter with multi-differential measurements of hadrons and leptons, including rare probes like multi-strange anti-hyperons and charmed particles. The research program covers the study of the high-density equation-of-state of nuclear matter, and the exploration of the QCD phase diagram at large baryon-chemical potentials, including the search for quark matter and the critical endpoint of a hypothetical 1st order phase transition. The CBM setup comprises detector systems for the identification of charged hadrons, electrons, and muons, for the determination of collision centrality and the orientation of the reaction plane, and a free-streaming data read-out and acquisition system, which allows online reconstruction and selection of events up to reaction rates of 10 MHz. In this article, emphasis is placed on the measurement of muon pairs in Au-Au collisions at FAIR beam energies, which are unique probes to determine the temperature of the fireball, and, hence, to search for a caloric curve of QCD matter. Simultaneously, the subthreshold production of charmonium can be studied via its dimuon decay, in order to shed light on the microscopic structure of QCD matter at high baryon densities. The CBM setup with focus on dimuon measurements and results of the corresponding physics performance studies will be presented.

   nucl-exParticles(2021)·5 citations
2. 02*

   Measurement of the Sixth-Order Cumulant of Net-Proton Multiplicity Distributions in Au+Au Collisions at $\sqrt{s_{\mathrm{NN}}}=$ 27, 54.4, and 200 GeV at RHIC

   STAR Collaboration: M. S. Abdallah · J. Adam · L. Adamczyk · J. R. Adams · J. K. Adkins · G. Agakishiev · I. Aggarwal · M. M. Aggarwal · Z. Ahammed · I. Alekseev · D. M. Anderson · A. Aparin and 381 other authors

   According to first principle Lattice QCD calculations, the transition from quark-gluon plasma to hadronic matter is a smooth crossover in the region ${\mu }_{\mathrm{B}}\le T_c$. In this range the ratio, $C_6/C_2$, of net-baryon distributions are predicted to be negative. In this paper, we report the first measurement of the midrapidity net-proton $C_6/C_2$ from 27, 54.4 and 200 GeV Au+Au collisions at RHIC. The dependence on collision centrality and kinematic acceptance in ($p_T$, $y$) are analyzed. While for 27 and 54.4 GeV collisions the $C_6/C_2$ values are close to zero within uncertainties, it is observed that for 200 GeV collisions, the $C_6/C_2$ ratio becomes progressively negative from peripheral to central collisions. Transport model calculations without critical dynamics predict mostly positive values except for the most central collisions within uncertainties. These observations seem to favor a smooth crossover in the high energy nuclear collisions at top RHIC energy.

   nucl-exhep-exhep-phnucl-thPRL(2021)·76 citations
3. 03*

   The isoscalar monopole strength of 13C

   S. Shin🇲🇦 · B. Zhou🇯🇵 · M. Kimura🇯🇵

   To identify the 3alpha BEC state with the excess neutron, we have investigated the monopole strength of the excited states of 13C by using the theoretical framework of the real-time evolution method. The calculations have revealed several candidates of the Hoyle-analog states in a highly excited region.

   ↳ nucl-thnucl-exFew Body Syst.(2021)·2 citations
4. 04*

   Multiplicity Scaling of Light Nuclei Production in Relativistic Heavy-Ion Collisions

   Wenbin Zhao🇨🇳 · Kai-jia Sun🇺🇸 · Che Ming Ko🇺🇸 · Xiaofeng Luo🇨🇳

   Using the nucleon coalescence model based on kinetic freeze-out nucleons from the 3D MUSIC+UrQMD and the 2D VISHNU hybrid model with a crossover equation of state, we study the multiplicity dependence of deuteron ($d$) and triton ($t$) production from central to peripheral Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}=$ 7.7, 14.5, 19.6, 27, 39, 62.4 and 200 GeV and Pb+Pb at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV, respectively. It is found that the ratio $N_t{N}_p/N_d^2$ of the proton yield $N_p$, deuteron yield $N_d$ and triton yield $N_t$ exhibits a scaling behavior in its multiplicity dependence, i.e., decreasing monotonically with increasing charged-particle multiplicity. A similar multiplicity scaling of this ratio is also found in the nucleon coalescence calculation based on kinetic freeze-out nucleons from a multiphase transport (AMPT) model. The scaling behavior of $N_t{N}_p/N_d^2$ can be naturally explained by the interplay between the sizes of light nuclei and the nucleon emission source. We further argue that the multiplicity scaling of $N_t{N}_p/N_d^2$ can be used to validate the production mechanism of light nuclei, and the collision energy dependence of this yield ratio can further serve as a baseline in the search for the QCD critical point in relativistic heavy-ion collisions.

   ↳ nucl-thhep-exhep-phnucl-exPLB(2021)·47 citations
5. 05*

   A systematic analysis of transverse momentum spectra of $J/\psi$ mesons in high energy collisions

   Xu-Hong Zhang🇨🇳 · Fu-Hu Liu🇨🇳 · Khusniddin K. Olimov🇺🇿

   We aggregate the transverse momentum spectra of $J/\psi$ mesons produced in high energy gold-gold (Au-Au), deuteron-gold ($d$-Au), lead-lead (Pb-Pb), proton-lead ($p$-Pb), and proton-(anti)proton ($p$-$p(\overline{p})$) collisions measured by several collaborations at the Relativistic Heavy Ion collider (RHIC), the Tevatron Proton-Antiproton Collider, and the Large Hadron Collider (LHC). The collision energy (the center-of-mass energy) gets involved in a large range from dozens of GeV to 13 TeV (the top LHC energy). We consider two participant or contributor partons, a charm quark and an anti-charm quark, in the production of $J/\psi$. The probability density of each quark is described by means of the modified Tsallis--Pareto-type function (the TP-like function) while considering that both quarks make suitable contributions to the $J/\psi$ transverse momentum spectrum. Therefore, the convolution of two TP-like functions is applied to represent the $J/\psi$ spectrum. We adopt the mentioned convolution function to fit the experimental data and find out the trends of the power exponent, effective temperature, and of the revised index with changing the centrality, rapidity, and collision energy. Beyond that, we capture the characteristic of $J/\psi$ spectrum, which is of great significance to better understand the production mechanism of $J/\psi$ in high energy collisions.

   ↳ hep-phhep-exnucl-exnucl-thIJMPE(2021)·9 citations
6. 06*

   Exclusive electro-weak production of a charmed meson at high energy

   B. Pire🇫🇷 · L. Szymanowski🇵🇱 · J. Wagner🇵🇱

   Exclusive electro-weak processes have peculiar features which make them complementary to usually discussed deeply virtual electroproduction processes such as deep virtual Compton scattering or meson production (and the corresponding crossed reactions). They allow in particular single charmed meson production, which we study in two different contexts : electroproduction at an electron ion collider and neutrino-production at a medium energy neutrino facility. We rely on the QCD collinear factorization framework where generalized parton distributions allow physicists to perform a nucleon tomography.

   ↳ hep-phhep-exnucl-exSciPost Phys.Proc.(2022)·1 citation

* 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.