Time-reversal odd fragmentation and distribution functions in pp and ep single spin asymmetries

TL;DR

This paper estimates T-odd fragmentation and distribution functions based on experimental data, showing their role in single spin asymmetries in proton-proton and electron-proton collisions, and making predictions for future experiments.

Contribution

It provides the first estimates of T-odd functions from data and links them to observed asymmetries, offering predictions for ep collisions.

Findings

The ratio $H_1^{ot}/D_1$ agrees with DELPHI data.

T-odd functions can explain single spin asymmetries.

Predictions made for electron-proton asymmetries.

Abstract

We present some estimates of T-odd fragmentation and distribution functions, $H_1^\perp$ and $f_{1T}^{\perp}$, evaluated on the basis of a fit on experimental data in p$^\uparrow$p. Assuming the T-odd fragmentation function to be responsible for the single spin asymmetry in pion production in p$^\uparrow$p, we find the ratio $H_1^{\perp}/D_1$ to be in good agreement with the experimental results from DELPHI data on Z -> 2$-jet decay. We use our estimates to make predictions for ep$^\uparrow$.