Transversity Signals in Two-Hadron Production at COMPASS

TL;DR

This paper reports on measurements of single spin asymmetries in two-hadron production from deep-inelastic scattering, providing insights into the transversity distribution of quarks using COMPASS data.

Contribution

It presents new experimental results on azimuthal asymmetries in pion and kaon pairs, contributing to the understanding of transversity distributions in nucleons.

Findings

Asymmetries on deuteron are compatible with zero.

Data supports the convolution model of transversity and interference fragmentation functions.

Results constrain models of quark transverse spin distributions.

Abstract

New results on single spin asymmetries of identified charged pion and kaon pairs produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in the years 2003 and 2004 with the COMPASS spectrometer at CERN with a 160 GeV muon beam from the CERN SPS accelerator. The asymmetries can be interpreted in the context of transversity as a convolution of the chiral-odd interference fragmentation function $H_1^\sphericalangle$ with the transverse spin distribution of quarks $\Delta_Tq(x)$. The measured azimuthal target spin asymmetries on the deuteron are compatible with zero within a small statistical error of about 1%.