\Delta G/G results from the COMPASS experiment for Q^2 > 1 GeV^2, using high p_T hadrons

TL;DR

This paper reports a new, more precise measurement of the gluon polarization  G/G in the nucleon using high p_T hadron pairs from the COMPASS experiment, incorporating data from 2002-2006 and advanced neural network analysis.

Contribution

It provides the first  G/G measurement for Q^2 > 1 GeV^2 with improved precision and binning, utilizing a neural network approach for better process identification.

Findings

Enhanced  G/G precision with 2006 data inclusion

First measurement of  G/G in three x_G bins for Q^2 > 1 GeV^2

Neural network method improves process separation accuracy

Abstract

One of the goals of COMPASS experiment is the determination of the gluon polarisation, \Delta G/G, for a deep understanding of the spin structure of the nucleon. The gluon polarisation can be measured via the Photon-Gluon-Fusion (PGF) process. One of the methods to identify this process is selecting high p_T hadron pairs in the final state. The data used for this analysis were collected by the COMPASS experiment during the years 2002 to 2006, using a 160 GeV naturally polarised positive muon beam impinging on a polarised nucleon target. A new result of \Delta G/G from high p_T hadron pairs in events with Q^2>1 GeV^2 is presented. This result has a better precision due to the addition of 2006 data and an improved analysis based on a neural network approach. The gluon polarisation is also presented in three bins of x_G.