K/pi Fluctuations at Relativistic Energies

Abstract

We report results for $K/pi$ fluctuations from Au_s16Au collisions at $sqrt{s_{NN}}$ = 19.6, 62.4, 130, and 200 GeV using the STAR detector at the Relativistic Heavy Ion Collider. Our results for $K/pi$ fluctuations in central collisions show little dependence on the incident energies studied and are on the same order as results observed by NA49 at the Super Proton Synchrotron in central Pb_s16Pb collisions at $sqrt{s_{NN}}$ = 12.3 and 17.3 GeV. We also report results for the collision centrality dependence of $K/pi$ fluctuations as well as results for $K^{_s16}/pi^{_s16}$, $K^{-}/pi^{-}$, $K^{_s16}/pi^{-}$, and $K^{-}/pi^{_s16}$ fluctuations. We observe that the $K/pi$ fluctuations scale with the multiplicity density, $dN/deta$, rather than the number of participating nucleons.