Apr 8 – 12, 2024
Maison MINATEC, Grenoble, FRANCE
Europe/Paris timezone

Transverse Single Spin Asymmetry of Electromagnetic Jets for Inclusive and Single Diffractive Process at Forward Rapidity in p^{\uparrow}+p Collisions at \sqrt{s} = 200 GeV at STAR

Apr 10, 2024, 4:20 PM
Maison MINATEC, Grenoble, FRANCE

Maison MINATEC, Grenoble, FRANCE

3 Parv. Louis Néel, 38054 Grenoble
Regular parallel talk WG5: Spin and 3D Structure WG5


Xilin Liang (University of California, Riverside)


In recent decades, there have been numerous efforts to unravel the origin of the unexpectedly significant transverse single spin asymmetry ($A_{N}$) observed in inclusive hadron productions at forward rapidities in $p^{\uparrow}$+$p$ collisions at various center-of-mass energies ($\sqrt{s}$). Several theories have been proposed to explain this phenomenon, including the twist-3 contributions within the collinear factorization framework, the transverse-momentum-dependent contributions from the initial-state quark and gluon (Sivers functions), and/or final-state Collins fragmentation functions. However, there are indications that diffractive processes might also play a role in the observed significant $A_{N}$, based on the previous analyses of $A_{N}$ for forward $\pi^{0}$ and electromagnetic jets (EM-jets) in $p^{\uparrow}$+$p$ collisions at STAR [1].

The STAR experiment provides an ideal opportunity to investigate the $A_{N}$ in single diffractive processes at forward rapidity using the Forward Meson Spectrometer and Roman Pot detectors.
This talk will present the preliminary findings on $A_{N}$ for both inclusive and single diffractive EM-jets at forward rapidity ($2.6 < \eta < 4.2$) in $p^{\uparrow}$+$p$ collisions at $\sqrt{s} =$ 200 GeV at STAR. The discussion will include a multi-dimensional analysis of $A_{N}$ for EM-jets in inclusive processes, with a focus on presenting the first preliminary results for $A_{N}$ in single diffractive processes. Additionally, there will be a discussion on the contribution of $A_{N}$ from single diffractive processes to the overall inclusive processes.

[1] (STAR) J. Adam et, al., Phys. Rev. D 103, 092009 (2021)

Primary author

Xilin Liang (University of California, Riverside)

Presentation materials