STAR's Measurement of Energy and System Size Dependence of K/$\pi$ Fluctuations at RHIC

TL;DR

This paper measures the energy and system size dependence of K/π fluctuations in heavy-ion collisions at RHIC, providing insights into strangeness production and potential signals of quark-gluon plasma formation.

Contribution

It presents new measurements of K/π fluctuations across different energies and system sizes at RHIC, comparing them with SPS results and theoretical models.

Findings

Fluctuation strength at highest SPS energy is similar to RHIC results.

K/π fluctuations vary with system size and energy.

Results are consistent with certain theoretical models.

Abstract

Strangeness enhancement has been predicted to be one of the signatures of the formation of the quark gluon plasma (QGP) and event-by-event fluctuations of strangeness may reveal the nature of such a phase transition. We report results for $K/\pi$ fluctuations from Cu+Cu at $\sqrt{s_{NN}}$ = 62.4 and 200 GeV and Au+Au collisions at $\sqrt{s_{NN}}$ = 62.4, 130 and 200 GeV using the STAR detector at the Relativistic Heavy Ion Collider. We compare our results with the results observed in central Pb+Pb collisions at SPS energies at $\sqrt{s_{NN}}$ = 6.3, 7.6, 8.8, 12.3, and 17.3 GeV. We observe the fluctuation strength measured at the highest SPS energy point by the NA49 collaboration in Pb+Pb collisions is similar to our results in Cu+Cu and Au+Au collisions. We also compare our results with HIJING, a statistical hadronization model and a multi-phase transport model.