Modeling spin effects in electron-positron annihilation to hadrons

The string+${}^3{P}_0$ model of spin-dependent hadronization is applied to the fragmentation of a string stretched between a quark and an antiquark with entangled spin states, assumed to be produced in the $e^{+}{e}^{-}$ annihilation process. The model accounts systematically for the spin correlations in the hadronization chain and is formulated as a recursive recipe suitable for the implementation in a Monte Carlo event generator. The recipe is applied to the production of two back-to-back pseudoscalar mesons produced in $e^{+}{e}^{-}$ annihilation, and it is shown to reproduce the form of the azimuthal distribution of the hadrons as expected in QCD.