Speaker
Description
Over the past several decades, numerous experiments have observed nonzero transverse single-spin asymmetries ($A_{\mathrm{N}}$) in forward hadron production. Although theoretical frameworks have been developed to describe these phenomena, their underlying mechanisms are not yet fully understood. The RHICf Collaboration reported a large non-zero $A_{\mathrm{N}}$ for forward neutral pion ($\pi^{0}$) production at $\eta > 6$ in transversely polarized $p+p$ collisions at $\sqrt{s}=510$ GeV. The RHICf result, considered in the context of the STAR measurement of the $A_{\mathrm{N}}$ for forward (2.7 $<\eta<$ 4.0) $\pi^{0}$s, suggests that diffractive interactions may play a major role in the observed $A_{\mathrm{N}}$. In this talk, we present the preliminary results on the contributions of single-diffractive, double-diffractive, and non-diffractive processes to the $A_{\mathrm{N}}$ for forward $\pi^{0}$ using the RHICf and STAR combined analysis.