STAR Results from Polarized Proton Collisions at RHIC

TL;DR

This paper reports on initial results from polarized proton collisions at RHIC, aiming to understand the proton's spin structure by measuring gluon and quark contributions through STAR experiment data.

Contribution

It presents early experimental results from STAR at RHIC that contribute to understanding the spin composition of the proton, focusing on gluon and quark flavor contributions.

Findings

Initial measurements of gluon polarization contributions.

Insights into quark flavor contributions to proton spin.

Data supporting the spin sum rule analysis.

Abstract

This talk reports on progress from the first two years of polarized proton collisions at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). STAR is one of the two large experiments at RHIC. It features large acceptance spanning a broad range of rapidity. The long-term goals of the STAR spin program are to measure the gluon contribution to the proton's spin; determine the contribution of specific quark flavors to the spin of the proton through the study of spin observables for vector boson production, and to determine the transversity structure function. The study of polarized proton collisions at $\sqrt{s}$=200 and 500 GeV is expected to provide important insight into the spin structure of the proton, revealing the contributions to the spin sum rule either from gluons or from the orbital motion of the partons. Selected STAR results from the study of polarized proton collisions during the first two runs are presented.