Induced second-class form factors inΣ−β decay

A study of induced second-class currents emerging as a consequence of broken SU(3) flavor symmetry in ${\Sigma }^{\mathrm{-}}$ β decay is presented. Working within the framework of the MIT bag model, all form factors describing the ${\Sigma }^{\mathrm{-}}$→n weak transition are calculated, including QCD vertex corrections to order ${\alpha }_s$. It is found that the weak-electric dipole form factor $g_2$ is suppressed by confinement effects to be approximately -0.1. This is shown to have a negligible effect on the electron asymmetry ${\alpha }_e$, and hence strengthens the case that recent data for ${\alpha }_e$ in ${\Sigma }^{\mathrm{-}}$ β decay are consistent with Cabibbo-model predictions.