Effect of sea quarks on single-spin asymmetries $A_N^{W^{\pm }}$ in transversely polarized pp collisions at RHIC

Abstract

We calculate the single-spin asymmetries $A_N^{W^{\pm }}$ of $W^{\pm }$ bosons produced in transversely polarized pp collisions with the valence part of the up (u) and down (d) quark Sivers functions treated by an available parametrization and the light-cone quark spectator-diquark model respectively, while the sea part Sivers functions of u and d quarks treated as parametrization. Comparing our results with those from experimental data at RHIC, we find that the Sivers functions of sea quarks play an important role in the determination of the shapes of $A_N^{W^{\pm }}$. It is shown that $A_N^{W^{-}}$ is sensitive to u sea Sivers function, while $A_N^{W^{+}}$ to d sea Sivers function intuitively. The results show that the contributions of u and d sea Sivers functions are rather sizable and of the same sign, and their signs agree with that of d valence quarks and are opposite to that of u valence quarks.

Comments: 14 latex pages, 6 figures, final published version