First measurements of Collins and Sivers asymmetries at COMPASS

TL;DR

This paper reports the first measurements of Collins and Sivers asymmetries in semi-inclusive deep inelastic scattering using a transversely polarized deuterium target at the COMPASS experiment, providing new insights into nucleon spin structure.

Contribution

It presents the first experimental results of Collins and Sivers asymmetries on a deuterium target at COMPASS, expanding understanding of transverse spin effects in nucleons.

Findings

First measurements of asymmetries on deuterium at COMPASS

Results indicate non-zero asymmetries, suggesting complex spin-momentum correlations

Data contribute to global understanding of nucleon transverse spin structure

Abstract

COMPASS is a fixed-target experiment on the SPS M2 beamline at CERN. Its LiD target can be polarised both longitudinally and transversally with respect to the longitudinally polarised 160 GeV/c muon beam. Approximately 20% of the beam-time in 2002, 2003 and 2004 was spent in the transverse configuration, allowing the first measurement of both the Collins and Sivers asymmetries on a deuterium target. First results from the the transverse data of the COMPASS run in 2002 are reported here.