Spin asymmetries for events with high p_T hadrons in DIS and an evaluation of the gluon polarization

TL;DR

This paper measures spin asymmetries in deep inelastic scattering with high p_T hadrons to evaluate gluon polarization, using neural network classification to enhance photon-gluon fusion events.

Contribution

It introduces a neural network-based method to classify events, increasing the photon-gluon fusion contribution and enabling a new measurement of gluon polarization in DIS.

Findings

Measured spin asymmetries for muon-nucleon interactions.

Derived gluon polarization delta(G)/G = -0.20 ± 0.28 ± 0.10.

Used neural network approach to improve event classification.

Abstract

We present a measurement of the longitudinal spin cross section asymmetry for deep inelastic muon-nucleon interactions with two high transverse momentum hadrons in the final state. Two methods of event classification are used to increase the contribution of the Photon Gluon Fusion process to above 30%. The most effective one, based on a neural network approach, provides the asymmetries A_p(lN->lhhX)=0.030+/-0.057+/-0.010 and A_d(lN->lhhX)=0.070+/-0.076+/-0.010. From these values we derive an averaged gluon polarization delta(G)/G=-0.20+/-0.28+/-0.10 at an average fraction of nucleon momentum carried by gluons eta=0.07.