Collins and Sivers transverse-spin asymmetries in inclusive muoproduction of $\rho^0$ mesons

TL;DR

This paper reports the first measurement of Collins and Sivers transverse-spin asymmetries in inclusive $ ho^0$ meson production during deep inelastic scattering, providing new insights into the nucleon's transverse spin structure.

Contribution

It presents the first experimental determination of Collins and Sivers asymmetries for $ ho^0$ mesons in inclusive deep inelastic scattering, using data from the COMPASS experiment.

Findings

Indications of positive Collins asymmetries.

Indications of positive Sivers asymmetries.

Asymmetries vary with kinematic variables.

Abstract

The production of vector mesons in deep inelastic scattering is an interesting yet scarsely explored channel to study the transverse spin structure of the nucleon and the related phenomena. The COMPASS collaboration has performed the first measurement of the Collins and Sivers asymmetries for inclusively produced $\rho^0$ mesons. The analysis is based on the data set collected in deep inelastic scattering in $2010$ using a $160\,\,\rm{GeV}/c$ $\mu^+$ beam impinging on a transversely polarized $\rm{NH}_3$ target. The $\rho^{0}$ mesons are selected from oppositely charged hadron pairs, and the asymmetries are extracted as a function of the Bjorken-$x$ variable, the transverse momentum of the pair and the fraction of the energy $z$ carried by the pair. Indications for positive Collins and Sivers asymmetries are observed.