Higher-twist contribution to fragmentation function in inclusive hadron production ine+e−annihilation

Abstract

We apply collinear expansion to inclusive hadron production in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation and derive a formalism suitable for systematic study of leading as well as higher-twist contributions to fragmentation functions at the tree level. We make the calculations for hadrons with spin-0, spin-$1/2$ as well as spin-1 and obtain the results in terms of different components of fragmentation functions for the hadronic tensors, the differential cross section as well as hadron polarizations in different cases. The results show a number of interesting features such as the existence of transverse polarization for spin-$1/2$ hadrons at the twist-3 level, the quark polarization independence of the spin alignment of vector mesons.