QCD evolution of naive-time-reversal-odd fragmentation functions

TL;DR

This paper derives QCD evolution equations for naive-time-reversal-odd fragmentation functions, revealing their kernels' relations to transversity and unpolarized functions, impacting global spin asymmetry analyses.

Contribution

It provides the first detailed derivation of QCD evolution kernels for the Collins and polarizing fragmentation functions, clarifying their relation to known functions.

Findings

The Collins function evolution kernel has a diagonal part identical to transversity.

The polarizing fragmentation function's kernel matches that of unpolarized fragmentation.

Results have significant implications for global spin asymmetry studies.

Abstract

We study QCD evolution equations of the first transverse-momentum-moment of the naive-time-reversal-odd fragmentation functions - the Collins function and the polarizing fragmentation function. We find for the Collins function case that the evolution kernel has a diagonal piece same as that for the transversity fragmentation function, while for the polarizing fragmentation function case this piece is the same as that for the unpolarized fragmentation function. Our results might have important implications in the current global analysis of spin asymmetries.