Study of the K- -> mu- nu pi0 decay
  The decay $K^{-} \to \mu^{-} \bar{\nu} \pi^{0}$ has been studied using in-flight decays detected with ``ISTRA+'' setup operating in the 25 GeV negative secondary beam of the U-70 PS. About 112K events were used for the analysis. The $\lambda_{+}$ and $\lambda_{0}$ slope parameters of the decay formfactors $f_{+}(t)$, $f_{0}(t)$ have been measured :   $\lambda_{+}= 0.0321 \pm 0.004$(stat) $\pm 0.002$(syst)   $\lambda_{0}= 0.0209 \pm 0.004$(stat) $\pm 0.002$(syst); the correlation $d \lambda_{0}/d \lambda_{+}=-0.46$ The limits on the possible tensor and scalar couplings have been derived:   $f_{T}/f_{+}(0)=-0.021 \pm 0.028$(stat) $\pm 0.014$(theory);   $f_{S}/f_{+}(0)=0.004 \pm 0.005$(stat) $\pm 0.005$(theory) 
I. Ajinenko, S. Akimenko, G. Britvich, I. Britvich, K. Datsko, A.   Filin, A. Inyakin, A. Konstantinov, V. Konstantinov, I. ...