TY - JOUR
T1 - Beam Energy Dependence of Fifth- and Sixth-Order Net-Proton Number Fluctuations in Au+Au Collisions at RHIC
AU - (STAR Collaboration)
AU - Aboona, B. E.
AU - Adam, J.
AU - Adamczyk, L.
AU - Adams, J. R.
AU - Aggarwal, I.
AU - Aggarwal, M. M.
AU - Ahammed, Z.
AU - Anderson, D. M.
AU - Aschenauer, E. C.
AU - Atchison, J.
AU - Bairathi, V.
AU - Baker, W.
AU - Ball Cap, J. G.
AU - Barish, K.
AU - Bellwied, R.
AU - Bhagat, P.
AU - Bhasin, A.
AU - Bhatta, S.
AU - Bielcik, J.
AU - Bielcikova, J.
AU - Brandenburg, J. D.
AU - Cai, X. Z.
AU - Caines, H.
AU - Calderón De La Barca Sánchez, M.
AU - Cebra, D.
AU - Ceska, J.
AU - Chakaberia, I.
AU - Chaloupka, P.
AU - Chan, B. K.
AU - Chang, Z.
AU - Chen, D.
AU - Chen, J.
AU - Chen, J. H.
AU - Chen, Z.
AU - Cheng, J.
AU - Cheng, Y.
AU - Choudhury, S.
AU - Christie, W.
AU - Chu, X.
AU - Crawford, H. J.
AU - Csanád, M.
AU - Dale-Gau, G.
AU - Das, A.
AU - Daugherity, M.
AU - Deppner, I. M.
AU - Dhamija, A.
AU - Di Carlo, L.
AU - Didenko, L.
AU - Dixit, P.
AU - Yang, Y.
N1 - Publisher Copyright:
© 2023 American Physical Society.
PY - 2023/2/24
Y1 - 2023/2/24
N2 - We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C5, C6) and factorial cumulants (κ5, κ6) of net-proton and proton number distributions, from center-of-mass energy (sNN) 3 GeV to 200 GeV Au+Au collisions at RHIC. Cumulant ratios of net-proton (taken as proxy for net-baryon) distributions generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at 3 GeV. The measured values of C6/C2 for 0%-40% centrality collisions show progressively negative trend with decreasing energy, while it is positive for the lowest energy studied. These observed negative signs are consistent with QCD calculations (for baryon chemical potential, μB≤110 MeV) which contains the crossover transition range. In addition, for energies above 7.7 GeV, the measured proton κn, within uncertainties, does not support the two-component (Poisson+binomial) shape of proton number distributions that would be expected from a first-order phase transition. Taken in combination, the hyperorder proton number fluctuations suggest that the structure of QCD matter at high baryon density, μB∼750 MeV at sNN=3 GeV is starkly different from those at vanishing μB∼24 MeV at sNN=200 GeV and higher collision energies.
AB - We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C5, C6) and factorial cumulants (κ5, κ6) of net-proton and proton number distributions, from center-of-mass energy (sNN) 3 GeV to 200 GeV Au+Au collisions at RHIC. Cumulant ratios of net-proton (taken as proxy for net-baryon) distributions generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at 3 GeV. The measured values of C6/C2 for 0%-40% centrality collisions show progressively negative trend with decreasing energy, while it is positive for the lowest energy studied. These observed negative signs are consistent with QCD calculations (for baryon chemical potential, μB≤110 MeV) which contains the crossover transition range. In addition, for energies above 7.7 GeV, the measured proton κn, within uncertainties, does not support the two-component (Poisson+binomial) shape of proton number distributions that would be expected from a first-order phase transition. Taken in combination, the hyperorder proton number fluctuations suggest that the structure of QCD matter at high baryon density, μB∼750 MeV at sNN=3 GeV is starkly different from those at vanishing μB∼24 MeV at sNN=200 GeV and higher collision energies.
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U2 - 10.1103/PhysRevLett.130.082301
DO - 10.1103/PhysRevLett.130.082301
M3 - Article
C2 - 36898098
AN - SCOPUS:85149659741
SN - 0031-9007
VL - 130
JO - Physical review letters
JF - Physical review letters
IS - 8
M1 - 082301
ER -