Beam energy dependence of net-Lambda fluctuations measured by the STAR experiment at the BNL Relativistic Heavy Ion Collider

0533941 - ÚJF 2021 RIV US eng J - Journal Article
Adam, J. - Adamczyk, L. - Adams, J. R. - Adkins, J. K. - Bielčík, J. - Bielčíková, Jana - Chaloupka, P. - Federič, Pavol - Holub, L. - Kocan, M. - Kosarzewski, L. K. - Kramárik, L. - Líčeník, Robert - Matonoha, O. - Moravcová, Z. - Rusňák, Jan - Rusňáková, O. - Šimko, Miroslav - Šumbera, Michal - Vaněk, Jan … Total 340 authors
Beam energy dependence of net-Lambda fluctuations measured by the STAR experiment at the BNL Relativistic Heavy Ion Collider.
Physical Review C. Roč. 102, č. 2 (2020), č. článku 024903. ISSN 2469-9985. E-ISSN 2469-9993
R&D Projects: GA MŠMT LTT18002
Research Infrastructure: BNL-CZ II - 90109
Institutional support: RVO:61389005
Keywords : STAR collaboration * heavy ion collision
OECD category: Nuclear physics
Impact factor: 3.296, year: 2020
Method of publishing: Open access
https://doi.org/10.1103/PhysRevC.102.024903

The measurements of particle multiplicity distributions have generated considerable interest in understanding the fluctuations of conserved quantum numbers in the quantum chromodynamics (QCD) hadronization regime, in particular near a possible critical point and near the chemical freeze-out. Net-protons and net-kaons have been used as proxies for the net-baryon number and net-strangeness, respectively. We report the measurement of efficiency- and centrality-bin width-corrected cumulant ratios (C-2/C-1,C-3/C-3) of net-A distributions, in the context of both strangeness and baryon number conservation, as a function of collision energy, centrality, and rapidity. The results are for Au + Au collisions at five beam energies (root s(NN) = 19.6, 27, 39, 62.4, and 200 GeV) recorded with the Solenoidal Tracker at RHIC (STAR). We compare our results to the Poisson and negative binomial (NBD) expectations, as well as to ultrarelativistic quantum molecular dynamics (UrQMD) and hadron resonance gas (HRG) model predictions. Both NBD and Poisson baselines agree with data within the statistical and systematic uncertainties. UrQMD describes the measured net-A C-1 and C-3 at 200 GeV reasonably well but deviates from C-2, and the deviation increases as a function of collision energy. The ratios of the measured cumulants show no features of critical fluctuations. The chemical freeze-out temperatures extracted from a recent HRG calculation, which was successfully used to describe the net-proton, net-kaon, and net-charge data, indicate A freeze-out conditions similar to those of kaons. However, large deviations are found when comparing with temperatures obtained from net-proton fluctuations. The net-A cumulants show a weak but finite dependence on the rapidity coverage in the acceptance of the detector, which can be attributed to quantum number conservation.
Permanent Link: http://hdl.handle.net/11104/0312168