Systematic study of charged-pion and kaon femtoscopy in Au$+$Au collisions at $\sqrt{s_{_{NN}}}$=200 GeV

TL;DR

This study systematically analyzes charged pion and kaon femtoscopy in high-energy gold-gold collisions, revealing differences in source sizes and azimuthal oscillations, with hydrodynamic models partially explaining the observations.

Contribution

It provides the first detailed comparison of pion and kaon femtoscopy, highlighting differences in source radii and azimuthal oscillations in heavy-ion collisions.

Findings

Kaon source radii are larger than pion radii in certain directions.

Oscillations of source radii are observed for both pions and kaons.

Hydrodynamic models qualitatively reproduce the oscillations but not their full mass dependence.

Abstract

We present a systematic study of charged pion and kaon interferometry in Au$+$Au collisions at $\sqrt{s_{_{NN}}}$=200 GeV. The kaon mean source radii are found to be larger than pion radii in the outward and longitudinal directions for the same transverse mass; this difference increases for more central collisions. The azimuthal-angle dependence of the radii was measured with respect to the second-order event plane and similar oscillations of the source radii were found for pions and kaons. Hydrodynamic models qualitatively describe the similar oscillations of the mean source radii for pions and kaons, but they do not fully describe the transverse-mass dependence of the oscillations.