Lattice QCD results on cumulant ratios at freeze-out

Abstract

Ratios of cumulants of net proton-number fluctuations measured by the STAR Collaboration show strong deviations from a skellam distribution, which should describe thermal properties of cumulant ratios, if proton-number fluctuations are generated in equilibrium and a hadron resonance gas (HRG) model would provide a suitable description of thermodynamics at the freeze-out temperature. We present some results on sixth order cumulants entering the calculation of the QCD equation of state at non-zero values of the baryon chemical potential (mu_B) and discuss limitations on the applicability of HRG thermodynamics deduced from a comparison between QCD and HRG model calculations of cumulants of conserved charge fluctuations. We show that basic features of the ${\mu }_B$-dependence of skewness and kurtosis ratios of net proton-number fluctuations measured by the STAR Collaboration resemble those expected from a O(mu_B^2) QCD calculation of the corresponding net baryon-number cumulant ratios.

6 pages, 10 figures, plenary talk given at Strange Quark Matter 2016, Berkeley, USA, 27 June 2016 - 1 July 2016

References in corpus (6)

• The equation of state in (2+1)-flavor QCD
• Additional Strange Hadrons from QCD Thermodynamics and Strangeness Freeze-out in Heavy Ion Collisions
• Hadron yields and the phase diagram of strongly interacting matter
• The melting and abundance of open charm hadrons
• Hadron Mass Spectrum from Lattice QCD
• Identified particle production and freeze-out properties in heavy-ion collisions at RHIC Beam Energy Scan program

Cited by in corpus (6)

• Collision energy dependence of the critical end point from baryon number fluctuations in the Linear Sigma Model with quarks
• Rapidity scan approach for net-baryon cumulants with a statistical thermal model
• Enhanced pion-to-proton ratio at the onset of the QCD phase transition
• Net-proton number cumulant ratios as function of beam energy from an expanding nonequilibrium chiral fluid
• Cumulants of the chiral order parameter at lower RHIC energies
• The time evolution of light nuclei cumulants and ratios with a first-order phase transition in the UrQMD transport model