Measurements of the $Z^{0}/\gamma^{*}$ cross section and transverse single spin asymmetry in 510 GeV $p$$+$$p$ collisions

TL;DR

This paper presents the first measurement of the differential cross section and transverse single spin asymmetry of Z0/γ* production in 510 GeV proton-proton collisions, providing insights into transverse momentum dependent parton distributions.

Contribution

It reports the first measurement of Z0/γ* differential cross section and TSSA in polarized proton-proton collisions at 510 GeV, advancing understanding of polarized TMDs.

Findings

First measurement of Z0/γ* differential cross section as a function of pT.

First measurement of Z0/γ* transverse single spin asymmetry in polarized p+p collisions.

Provides constraints on the Sivers function and TMD evolution.

Abstract

The differential cross section for $Z^{0}$ production, measured as a function of the boson's transverse momentum ($p_{\mathrm{T}}$), provides important constraints on the evolution of the transverse momentum dependent parton distribution functions (TMDs). The transverse single spin asymmetry (TSSA) of the $Z^{0}$ is sensitive to one of the polarized TMDs, the Sivers function, which is predicted to have the opposite sign in $p+p$ $\rightarrow W/Z+ X$ from that which enters in semi-inclusive deep inelastic scattering. In this Letter, the STAR Collaboration reports the first measurement of the $Z^{0}/\gamma^{*}$ differential cross section as a function of its $p_{\mathrm{T}}$ in $p$$+$$p$ collisions at a center-of-mass energy of 510 GeV, together with the $Z^{0}/\gamma^{*}$ total cross section. We also report the measurement of $Z^{0}/\gamma^{*}$ TSSA in transversely polarized $p$$+$$p$ collisions at 510 GeV.