Transversity and Collins Fragmentation Functions: Towards a New Global Analysis

TL;DR

This paper presents a new global analysis of experimental data to more precisely determine the transversity distribution and Collins fragmentation functions, enhancing understanding of spin asymmetries in semi-inclusive deep inelastic scattering and e+e- processes.

Contribution

It introduces a comprehensive global analysis incorporating recent data, improving the precision of transversity and Collins functions compared to previous studies.

Findings

More accurate transversity distributions for u and d quarks.

Refined Collins fragmentation functions from combined data.

Predictions for single spin asymmetries at JLab and COMPASS.

Abstract

A new, preliminary global analysis of the experimental data on azimuthal asymmetries in SIDIS from HERMES and COMPASS collaborations, and in e+e- --> h_1 h_2 X processes from the BELLE collaboration, is performed. The new data allow for a more precise determination of the Collins fragmentation function and of the transversity distribution function for $u$ and $d$ quarks, in comparison with the results of our previous analysis. Estimates for the single spin asymmetry A_UT^{\sin(\phi_h + \phi_S)} at JLab and COMPASS, operating on a transversely polarized proton target, are presented.