- Title: Multi-dimensional study of transverse single-spin asymmetries for electromagnetic jets at forward rapidities in polarized $pp$ collisions at $\sqrt{s}$ = 200 GeV

 - PAs: Kenneth Barish, Christopher Dilks, Carl Gagliardi, Latif Kabir, David Kapukchyan, Xilin Liang*, Mriganka Mondal

1.   FMS QA in spin PWG
2.   FMS simulation in spin PWG
3.   Preliminary request in spin PWG
4.   Systematic uncertainty in spin PWG
5.   DNP 2020 presentation
6.   GHP 2021 presentation
7.   SPIN 2021 presentation and proceeding

  -abstract: The STAR Collaboration reports measurements of the transverse single-spin asymmetries, $A_N$, for electromagnetic jets (EM-jets) in transversely polarized $pp$ collisions at $\sqrt{s}$ = 200 GeV in the pseudorapidity regions of $1.0<\eta<2.0$ and $2.8<\eta<3.8$. These results are presented as three-dimensional functions of the EM-jet Feynman-$x$ ($x_F$), transverse momentum ($p_T$), and photon multiplicity. $A_N$ is found to be strong functions of EM-jet $x_F$ and photon multiplicity, and a weaker function of EM-jet $p_T$.  These results can help to elucidate the dynamics underlying the large transverse single-spin asymmetries that have been observed for inclusive hadron production at forward rapidities.

 - Figure 1:

  Fig. 1: Transverse Single-Spin Asymmetry of the dependent of EM-jet p_T , energy, and photon multiplicity for the EM-jet at 2.8 < eta < 3.8. The bottom panel are the average x_F for each p_T bin.

  Figure 2:

  Fig. 2: Transverse single-spin asymmetry for EM-jet at 2.8 < eta < 3.8 as a function of EM-jet x_F with 3 different EM-jet photon multiplicity cases. 

  Figure 3:

  Fig. 3: Transverse single-spin asymmetry for the EM-jet at 1.0 < eta < 2.0 as the dependent of EM-jet p_T and photon multiplicity. The bottom panel are the average x_F for each p_T bin.