Strange freezeout

Abstract

We argue that known systematics of hadron cross sections may cause different particles to freeze out of the fireball produced in heavy-ion collisions at different times. We find that a simple model with two freezeout points is a better description of data than that with a single freezeout, while still remaining predictive. The resulting fits seem to present constraints on the late stage evolution of the fireball, including the tantalizing possibility that the QCD chiral transition influences the yields at sqrt(S)=2700 GeV and the QCD critical point those at sqrt(S)=17.3 GeV

Melting and freeze-out conditions of hadrons in a thermal medium

“…We provide evidences of a flavor-nonuniversal deconfinement and freeze-out conditions that support previous results in this directions [3][4][5]. On one hand, using the PNJL model we observe that multistrange hadrons melt at higher temperatures rather systematically.…”

“…Therefore, there exist indications of a flavor hierarchy in (at least) two different observables: the QCD phase transition and the freeze-out temperatures [4]. This issue have created much interest at this SQM2017 conference, e.g.…”

AntimatterHΛ4hypernucleus production and theHΛ3Sun1, Chen2 2016Phys. Rev. C271170View full textAdd to dashboardCite

“…The Λ particles thus have a higher freezeout temperature than nucleons, especially at RHIC, implying an earlier freezeout for Λ particles than for nucleons, which is consistent with the empirical picture that the strange baryons usually freeze out earlier than the nonstrange baryons due to their relatively smaller interaction cross sections. The earlier Λ freezeout is also supported by the investigation on strangeness production [19,[45][46][47][48] as well as the microscopic transport model simulations [49].…”

Transverse-momentum spectra of strange particles produced in Pb + Pb collisions atsNN=2.76TeV in the chemical nonequilibrium model

“…With the reduced r max and other parameters unchanged, the model results agree with the experimental points even for Ω's measured at the highest measured centrality. To some extent, such an approach reminds the recent proposal of a two step freeze-out [72].…”