Induced second-class currents from isospin and chiral-symmetry breaking

Abstract

Isospin and chiral-symmetry breaking due to an ${\epsilon }_3{u}_3$ Hamiltonian are studied in connection with induced second-class vector currents. In the case of neutron $\beta$ decay it is found that the induced second-class coefficient is an order of magnitude larger than expected on naive grounds. Predictions for induced effects in ${\Sigma }^{-}\to \Lambda \beta$ decay, $\tau \to \delta {\nu }_{\tau }$, and $\pi \to e\nu \gamma$ are also presented.