T-odd quark fragmentation function and transverse spin asymmetries in the pion production

TL;DR

This paper investigates the T-odd quark fragmentation function's role in transverse spin asymmetries during pion production, highlighting non-perturbative effects and meson cloud influences on nucleon transversity.

Contribution

It introduces a method to extract the T-odd fragmentation function from polarized proton collisions and discusses meson cloud effects on transversity distributions.

Findings

T-odd fragmentation functions can arise from non-perturbative QCD dynamics.

The asymmetry for $mbda^-$ production is smaller than naive expectations.

Meson cloud effects significantly suppress the $d$-quark transversity.

Abstract

We study the time-reversal odd quark fragmentation function and its consequences on the hard processes. T-odd quark fragmentation function may arise, although QCD is T-invariant, from the non-perturbative dynamics in the fragmentation process. Assuming the factorization, we extract the T-odd fragmentation function from the inclusive pion production in the transversely polarized proton-proton collision. We then estimate the single spin asymmetry $A_{OT}$ of the semi-inclusive deep inelastic scattering with unpolarized lepton and the transversely polarized proton. We also discuss the meson cloud effects on the transversity distribution $h_1(x)$ of the nucleon. Asymmetry for the $\pi^-$ production is found to be much smaller than the naive expectation, since the $d$-quark transversity is considerably suppressed by the pion cloud effects