Recursive model for the fragmentation of polarized quarks

Abstract

We present a model for Monte Carlo simulation of the fragmentation of a polarized quark. The model is based on string dynamics and the ${}^3{P}_0$ mechanism of quark pair creation at string breaking. The fragmentation is treated as a recursive process, where the splitting function of the subprocess $q\to h+q^{\prime }$ depends on the spin density matrix of the quark $q$. The ${}^3{P}_0$ mechanism is parametrized by a complex mass parameter $\mu$, the imaginary part of which is responsible for single spin asymmetries. The model has been implemented in a Monte Carlo program to simulate jets made of pseudoscalar mesons. Results for single hadron and hadron pair transverse-spin asymmetries are found to be in agreement with experimental data from SIDIS and $e^{+}{e}^{-}$ annihilation. The model predictions on the jet-handedness are also discussed.

Comments: 18 pages, 18 figures