Test the time-reversal modified universality of the Sivers function

TL;DR

This work calculates the single transverse-spin asymmetry of inclusive lepton from the decay of W bosons in polarized proton-proton collision at the Brookhaven National Laboratory Relativistic Heavy Ion Collider (RHIC), and argues that this measurable lepton asymmetry at RHIC is an excellent observable for testing the time-reversal modified universality of the Sivers function.

Abstract

We derive the time-reversal modified universality for both quark and gluon Sivers function from the parity and time-reversal invariance of QCD. We calculate the single transverse-spin asymmetry of inclusive lepton from the decay of $W$ bosons in polarized proton-proton collision at RHIC, in terms of the Sivers function. We find that although the asymmetry is diluted from the $W$ decay, the lepton asymmetry is at the level of several percent and is measurable for a good range of lepton rapidity at RHIC. We argue that this measurable lepton asymmetry at RHIC is an excellent observable for testing the time-reversal modified universality of the Sivers function.

Figures (4)

• Figure 1: $A_N$ as a function of $W$-boson rapidity.
• Figure 2: $A_N$ as a function of $W$-boson transverse momentum.
• Figure 3: $A_N$ as a function of lepton rapidity.
• Figure 4: $A_N$ as a function of lepton transverse momentum.