Braguta V.V., Likhoded A.A., Chalov A.E
"Muon transverse polarization in the $K_{l2\gamma}$ process within
the SM and three Higgs doublets Weinberg model"

hep-ph/0105111 

      Abstract
  We consider two possible sources of the $T$-violating muon transverse 
polarization in the process $K^+ \to \mu^+ \nu \gamma$: electromagnetic final 
state interaction in the SM and contribution due to charged-Higgs exchange 
diagrams in the framework of the Weinberg three doublets model. It is shown 
that at the one-loop level of the SM the muon transverse polarization, 
$P_T^{SM}$, varies within $(0.0 \div 1.1 \cdot 10^{-3})$ in the Dalitz plot 
region. Averaged value of the muon polarization, $<P^{SM}_T>$, in the 
kinematic region of $E_\gamma \geq 20$ MeV is equal to $4.76\cdot 10^{-4}$. In
the case of the model with three Higgs doublets the muon transverse 
polarization is calculated as a function of charged Higgs masses, imaginary 
part of the Yukawa coupling constants product and vacuum expectation values of
the Higgs doublets. The averaged value of the transverse polarization in the 
Weinberg model is $<P^{Higgs}_T > = - 6.62 \cdot 10^{-5}$. Perspectives to 
probe the effect caused by the charged Higgs exchange diagrams in planned kaon
experiments are discussed.