Update on extraction of transversity PDF from inclusive di-hadron production

TL;DR

This paper updates the extraction of the transversity parton distribution function using inclusive di-hadron production data from semi-inclusive deep-inelastic scattering and proton-proton collisions, incorporating recent STAR results.

Contribution

It presents the first preliminary global fit of transversity combining data from different hard processes, including recent STAR measurements.

Findings

Enhanced constraints on transversity from new data

First combined global fit of transversity using di-hadron production

Improved understanding of transversity's role in hadronization processes

Abstract

The transversity was recently extracted from data on the production of hadron pairs in semi-inclusive deep-inelastic scattering. This analysis can be conveniently performed in the framework of collinear factorization where the elementary mechanism is represented by the simple product of transversity and of a suitable chiral-odd function describing the fragmentation of a transversely polarized parton into a pair of hadrons inside the same current jet. The same elementary mechanism was predicted long ago to generate an asymmetry in the azimuthal distribution of the hadron pairs when they are produced in proton-proton collisions with one transversely polarized proton. Recently, the STAR Collaboration has observed this asymmetry. We analyze the impact of these data on our knowledge of transversity and we present its first preliminary extraction from a global fit of all data in hard processes with inclusive di-hadron production.