Muon transverse polarization in the $K_{l2\gamma }$ decay in SM

Abstract

The muon transverse polarization in the $K^{+}\to {\mu }^{+}\nu \gamma$ process induced by the electromagnetic final state interaction is calculated in the framework of Standard Model. It is shown that one loop contributions lead to a nonvanihing muon transverse polarization. The value of the muon transverse polarization averaged over the kinematical region of $E_{\gamma }\ge 20$ MeV is equal to $5.63\times 10^{-4}$.

Comments: 18 pages, 4 figures