Speaker
Dr
Mriganka Mouli Mondal
(Texas A&M University)
Description
Large transverse single-spin asymmetries ($A_N$) have been observed
for forward inclusive hadron production in $p+p$ collisions at
various experiments. In the collinear perturbative scattering
picture, twist-3 multi-parton correlations can give rise to such an
asymmetry. A transversely polarized quark can also give rise to a
spin-dependent distribution of its hadron fragments via the
higher twist equivalents of the Collins fragmentation function.
The observed $A_N$ may involve contributions from both processes.
These can be disentangled by studying asymmetries for jets, direct
photons and jet-fragments.
The STAR Forward Meson Spectrometer (FMS), a Pb-glass electromagnetic
calorimeter covering the pseudo-rapidity ($\eta$) range 2.6-4.2 and full
azimuth, can detect photons, neutral pions and eta mesons. We are
measuring $A_N$ for $\pi^{0}$ and jet-like events reconstructed
from photons in the FMS in $p+p$ collisions at $\sqrt{s}$ = 500 GeV
that were recorded during the 2011 RHIC run. We study $A_N$ as a function of
the number of observed photons in FMS, thereby exploring asymmetries
for a range of event classes. We further study $A_N$ for forward jets
and its dependency with forward-midrapidity jet correlation. The current
status of the analysis will be discussed.
Author
Dr
Mriganka Mouli Mondal
(Texas A&M University)
