Correlation functions in charged kaon femtoscopy in Au+Au collisions at √sNN = 200 GeV at STAR

One-dimensional two-kaon correlation functions in Au+Au collisions at √ sNN = 200 GeV have been studied using the STAR (solenoidal tracker at RHIC) detector at the Relativistic Heavy Ion Collider. The experimental correlation of the particles was measured by taking the ratio of distribution in momentum difference for the pair of particles from the same event and the corresponding distribution for the pair of particles from different event. The centrality and the transverse momentum dependencies as a function of the Q-invariance were determined. The source sizes, out-side-long (qo, qs and ql) were measured according to the Bertsch-Pratt parametrization, where ‘out’ means along the pair transverse momentum, kT , ‘long’ is parallel to the beam direction, z, and ‘side’ is oriented perpendicular to ‘out’ and ‘long’. We observed the correlations decreased from higher to lower transverse momentum and increased from peripheral to central collisions. There were large track merging effects as the centrality increase and relative momentum decrease for the three measured (qo, qs and ql) components. qo and ql increase rapidly as centrality increases and kT decreases. qs shows a rather slow centrality and kT dependence. The centrality and transverse momentum dependencies on the Q-invarance was compared with preliminary result for Au+Au collisions at √ sNN= 130 GeV.