# Transversity distributions from difference asymmetries in semi-inclusive DIS

## TL;DR

This paper presents a novel method to extract the ratio of u and d quark transversity distributions from SIDIS data alone, avoiding the need for $e^+e^-$ data, and applies it to COMPASS data.

## Contribution

The paper introduces an alternative approach to determine transversity ratios using difference asymmetries in SIDIS without relying on $e^+e^-$ data.

## Key findings

- Successfully extracted the $h_1^d/h_1^u$ ratio from COMPASS data.
- Compared results with previous methods using SIDIS and $e^+e^-$ data.
- Validated the new method's consistency with existing measurements.

## Abstract

In recent years information on the transversity distribution $h_1$ has been obtained combining the Collins asymmetry results from semi-inclusive deep inelastic scattering (SIDIS) data on transversely polarized nucleon targets with the information on the fragmentation function of a transversely polarized quark from the asymmetries measured in $e^+e^-$ annihilation into hadrons. An alternative method was proposed long time ago, which does not require the $e^+e^-$ data, but allows one to get ratios of the $u$ and $d$ quark transversity distributions from the SIDIS data alone. The method utilizes the ratio of the difference of the Collins asymmetries of positively and negatively charged hadrons produced on transversely polarized proton and deuteron targets. We have applied this method to the COMPASS proton and deuteron data, and extracted the ratio $h_1^d/h_1^u$. The results are compared to those obtained in a previous point--by--point extraction based both on SIDIS and $e^+e^-$ data.