Status and prospects of Di-jet production in high-energy polarized proton-proton collisions at RHIC at s**(1/2) = 200-GeV

TL;DR

This paper reviews the status and future prospects of di-jet production measurements in polarized proton-proton collisions at RHIC, aiming to improve understanding of the proton's gluon spin contribution within Quantum Chromodynamics.

Contribution

It reports on recent measurements of di-jet cross sections and double-spin asymmetries at RHIC, highlighting their role in constraining the polarized gluon distribution function g.

Findings

Di-jet measurements provide direct access to initial parton kinematics.

Recent data constrains the polarized gluon distribution g.

Future measurements will further refine understanding of proton spin structure.

Abstract

The STAR experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) is carrying out a spin physics program colliding transversely or longitudinally polarized proton beams at = 200-500 GeV to gain deeper insigh t into the spin structure and dynamics of the proton. These studies provide fundamental insight into Quantum Chromodynamics (QCD). One of the main objectives is the determination of the polarized gluon distribution function, g, through the measurement of the longitudinal double-spin asymmetry, ALL, for various processes. Inclusive hadron and jet production from polarized pp collision data collected so far at = 200 GeV using the STAR detector at RHIC have placed important constraints on g. Di-jet producti on provides direct access to the initial parton kinematics at leading order (LO) QCD and thus provides sensitivity to the Bjorken-x dependence of g. The status of the mid-rapidity di-jet cross section analysis from the 2005 RHIC run and the longitudinal d ouble-spin asymmetry at mid-rapidity for the 2006 data sample are discussed in these proceedings. Projections on future di-jet measurements at STAR are provided.