Mon·Feb 1, 2021Monday·February 1, 2021

1. 01*

   Cumulants and Correlation Functions of Net-proton, Proton and Antiproton Multiplicity Distributions in Au+Au Collisions at energies available at the BNL Relativistic Heavy Ion Collider

   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 379 other authors

   We report a systematic measurement of cumulants, $C_n$, for net-proton, proton and antiproton multiplicity distributions, and correlation functions, ${\kappa }_n$, for proton and antiproton multiplicity distributions up to the fourth order in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4 and 200 GeV. The $C_n$ and ${\kappa }_n$ are presented as a function of collision energy, centrality and kinematic acceptance in rapidity, $y$, and transverse momentum, $p_T$. The data were taken during the first phase of the Beam Energy Scan (BES) program (2010 -- 2017) at the BNL Relativistic Heavy Ion Collider (RHIC) facility. The measurements are carried out at midrapidity ($|y|<$ 0.5) and transverse momentum 0.4 $<$ $p_{\mathrm{T}}$ $<$ 2.0 GeV/$c$, using the STAR detector at RHIC. We observe a non-monotonic energy dependence ($\sqrt{s_{\mathrm{NN}}}$ = 7.7 -- 62.4 GeV) of the net-proton $C_4$/$C_2$ with the significance of 3.1$\sigma$ for the 0-5\% central Au+Au collisions. This is consistent with the expectations of critical fluctuations in a QCD-inspired model. Thermal and transport model calculations show a monotonic variation with $\sqrt{s_{\mathrm{NN}}}$. For the multiparticle correlation functions, we observe significant negative values for a two-particle correlation function, ${\kappa }_2$, of protons and antiprotons, which are mainly due to the effects of baryon number conservation. Furthermore, it is found that the four-particle correlation function, ${\kappa }_4$, of protons plays a role in determining the energy dependence of proton $C_4/C_1$ below 19.6 GeV, which cannot be understood by the effect of baryon number conservation.

   nucl-exhep-exhep-phnucl-thPRC(2021)·227 citations
2. 02*

   Measures of pion and kaon structure from generalised parton distributions

   Jin-Li Zhang🇨🇳 · Khépani Raya🇨🇳 · Lei Chang🇨🇳 · Zhu-Fang Cui🇨🇳 · José Manuel Morgado🇪🇸 · Craig D. Roberts🇨🇳 · José Rodríguez-Quintero🇪🇸

   Pion and kaon structural properties provide insights into the emergence of mass within the Standard Model and attendant modulations by the Higgs boson. Novel expressions of these effects, in impact parameter space and in mass and pressure profiles, are exposed via $\pi$ and $K$ generalised parton distributions, built using the overlap representation from light-front wave functions constrained by one-dimensional valence distribution functions that describe available data. Notably, e.g. $K$ pressure profiles are spatially more compact than $\pi$ profiles and both achieve near-core pressures of similar magnitude to that found in neutron stars.

   ↳ hep-phhep-exhep-latnucl-ex+1PLB(2021)·42 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.