Speaker
Mr
Yan Yang
(Ohio State University)
Description
Correlations between non-identical particles at low relative momentum
in the center of mass ($|\vec{k}^*|$) encode unique information on the
space-time structure of the emitting system. In addition to size of
the homogeneity region, analysis of correlation functions in the three-
dimensional $\vec{k}^*$ space can reveal a space-time offset of one
particle species (e.g. kaons) with respect to another (e.g. pions). Early
results from STAR at $\sqrt{s_{NN}}$ = 130 GeV showed such an
asymmetry, which was consistent with collective radial flow. This early
analysis was hampered by the limited particle identification capabilities
of the STAR Time Projection Chamber, as well as from marginal statistics
and photon conversion due to a significant material budget close to the beam.
In year 2010 and year 2011, STAR had accumulated more than one billion
minimum bias events at $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions
with full Time of Flight detector in operation, which enables detailed
non-identical femtoscopy measurements.
We present new measurements of pion-kaon correlations in the more
sensitive spherical harmonic decomposition representation at
$\sqrt{s_{NN}}$ = 200 GeV collisions from these data sets with a lower
material budget and much higher statistics. The analysis greatly benefits
when information from the STAR Time of Flight detector is used to
extend particle identification capabilities. Centrality dependence of
pion-kaon femtoscopy in Au+Au collisions will be presented for the
first time. Finally, we present a first similar analysis of p+p collisions
at $\sqrt{s}$ = 200 GeV.
Primary author
Mr
Yan Yang
(Ohio State University)
