Transverse spin asymmetries for inclusive $\rho^0$ production in SIDIS at COMPASS

TL;DR

This paper reports the first measurement of transverse-spin asymmetries in inclusive $ ho^0$ production in SIDIS at COMPASS, providing new insights into polarized fragmentation phenomena.

Contribution

It presents the first experimental results of Collins and Sivers asymmetries for $ ho^0$ mesons in SIDIS, based on 2010 COMPASS data.

Findings

Indications of positive Collins asymmetries

Indications of positive Sivers asymmetries

Asymmetries vary with kinematic variables

Abstract

The production of vector mesons in SIDIS is a particularly interesting channel to study the polarized fragmentation and related phenomena. Preliminary COMPASS results for the first measurement of inclusive $\rho^0$ Collins and Sivers transverse-spin asymmetries are presented here for the first time. The analysis is based on the data-set collected by COMPASS in $2010$ using a $160\, \rm{GeV}/c$ $\mu^+$ beam and a transversely polarized $NH_3$ target. The asymmetries are extracted as function of Bjorken-$x$, of the total transverse momentum of the oppositely charged hadron pair and of the fraction of available energy $z$ carried by the pair. Indications for positive Collins and Sivers asymmetries are obtained as expected from models.