Transverse Single-Spin Asymmetries for Jet-like Events at Forward Rapidities in $p+p$ Collisions at $\sqrt{s}$ = 500 GeV with the STAR Experiment

ORAL

Abstract

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 Collins mechanism. 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 range 2.6-4.2 and full azimuth, can detect photons, neutral pions and eta mesons. We are measuring $A_N$ for 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, thereby exploring asymmetries for a range of event classes. The current status of the analysis will be discussed.

Authors

  • Mriganka Mouli Mondal

    Texas A\&M University