The Centrality Dependence of Strange Baryon and Meson Production in Cu+Cu and Au+Au sqrt(s_NN) = 200 GeV collisions

TL;DR

This study compares strange baryon and meson production in Cu+Cu and Au+Au collisions at 200 GeV, revealing how centrality affects particle yields and ratios, indicating increased strangeness production in Cu+Cu.

Contribution

It provides the first detailed comparison of Lambda and K0Short production across two collision systems at the same energy, highlighting system size effects on strangeness production.

Findings

Lambda yields are higher at mid-pT in Cu+Cu than in Au+Au for similar participant numbers.

Mid-pT Lambda/K0Short ratios increase with centrality in both systems.

Cu+Cu shows higher bulk strangeness production at comparable participant counts.

Abstract

Transverse momentum spectra of Lambda and K0Short particles are presented for Cu+Cu sqrt(s_NN) = 200 GeV collisions observed at STAR, and compared to Au+Au measurements at the same energy. For both systems, a number of observables are shown to increase at mid-rapidity (|y| < 0.5) with increasing centrality. These are the integrated Lambda and K0Short yields, the integrated Lambda and K0Short yields per participating nucleon, and mid-pT (1 GeV/c -> 4.5 GeV/c) Lambda/KK0Short ratios. The RCP ratio is found to be higher for the Lambda yields at mid-pT compared to the K0Short yields for both the Cu+Cu and Au+Au data. In contrast, when similar numbers of participating nucleons are considered for the Cu+Cu and Au+Au data, an indication of increased bulk strangeness production and a higher mid-pT (1 -> 4.5 GeV/c) Lambda/K0Short ratio are found, for Cu+Cu.