Kaon interferometric probes of space-time evolution in Au+Au collisions at sqrt(s_NN) = 200 GeV

TL;DR

This paper investigates the space-time evolution of particle emission in heavy ion collisions using Bose-Einstein correlations of charged kaons, revealing extended emission regions and deviations from Gaussian source distributions.

Contribution

It provides the first detailed analysis of kaon interferometry in Au+Au collisions at 200 GeV, comparing results with pion probes and identifying non-Gaussian tails in the emission source.

Findings

Kaon source radii scale linearly with N_part^{1/3}

Deviations from Gaussian emission profiles at large radii

Extended emission regions confirmed beyond resonance decay effects

Abstract

Bose-Einstein correlations of charged kaons are measured for Au+Au collisions at sqrt(s_NN) = 200 GeV and are compared to charged pion probes, which have a larger hadronic scattering cross section. Three dimensional Gaussian source radii are extracted, along with a one-dimensional kaon emission source function. The centrality dependences of the three Gaussian radii are well described by a single linear function if N_part^1/3 with zero intercept. Imaging analysis shows a deviation from a Gaussian tail at r >~ 10 fm, although the bulk emission at lower radius is well-described by a Gaussian. The presence of a non-Gaussian tail in the kaon source reaffirms that the particle emission region in a heavy ion collision is extended, and that similar measurements with pions are not solely due to the decay of long-lived resonances.