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The gluon Sivers asymmetry measurements at COMPASS

A. Szabelski, on behalf of the COMPASS Collaboration

in XXV International Workshop on Deep-Inelastic Scattering and Related Subjects

Contribution: pdf


The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons.
As such, a nonzero Sivers effect for gluons could be a signature of their nonzero orbital angular momentum inside the nucleon.
COMPASS has collected data of semi-inclusive deep inelastic scattering by impinging 160 GeV$/c$ muons on transversely polarised proton
and deuteron targets.
The gluon Sivers asymmetry is extracted from a high-$p_T$ hadron pair sample with the use of monte carlo simulations and the a neural network approach.
The results of a similar analysis for a Collins-like asymmetry for gluons will also be given.