Speaker
Description
The measurement of conserved charge distributions have generated considerable interest in understanding the cumulants of conserved quantum numbers in the crossover region of the QCD phase diagram, in particular near a possible critical end point and near a postulated common chemical freeze-out line. Initially net protons and net kaons have been used as proxies for the net baryon and strangeness numbers. We present the measurement of efficiency and feed-down corrected cumulant ratios (C2/C1, C3/C2) of net Λ as a function of centrality and rapidity for Au+Au collisions in the √sNN = 19.6 - 200 GeV range. Net Λ fluctuations are unique in that they are sensitive to strangeness (S) and baryon number (B) conservation effects as well as providing the main contribution to the baryon-strangeness (BS) correlator. Net Λ fluctuations also contribute to the determination of baryon number and strangeness freeze-out, in particular when combined with net proton and net kaon measurements. A comparison to the hadron resonance gas (HRG) model, which uses the latest hadronic spectrum from the 2016 PDG listings, seems to indicate a flavor dependence in the chemical freeze-out. In this context, we also compare our results to the previous STAR measurements, Poisson and negative binomial expectations, as well as UrQMD model predictions.
| Track | QCD phase diagram and critical point |
|---|---|
| Collaboration name | STAR Collaboration |
