Transverse polarization of the $\hat{I}›$ hyperon from unpolarized quark fragmentation in the diquark model

Abstract

We investigate the spin-dependent (naive) T-odd fragmentation function $D_{1T}^{\perp }$, which can provide an explanation on the transverse polarization of the $\hat{I}{›}^0$ hyperon produced in an unpolarized process. We calculate $D_{1T}^{\perp }$ for light flavors in the spectator diquark model, with a Gaussian form factor at the hyperon-quark-diquark vertex. We include in the calculation both the scalar diquark and axial-vector diquark spectators. We determine the values of the model parameters by fitting the unpolarized fragmentation function $D^{\hat{I}}{›}_1$ to the DSV parametrization for $D^{\hat{I}}{›}_1$. In addition, we compute the longitudinal polarization fragmentation function $G^{\hat{I}}{›}_1$ and compare it with the known parametrization of $G^{\hat{I}}{›}_1$. We also estimate the transverse polarizations of $\hat{I}›$ production, in both semi-inclusive deep inelastic scattering and single inclusive $e^{+}{e}^{-}$ annihilation.

Reference added, typos corrected