Measurement of K^+ \to π^0 μ^+ νγdecay using stopped kaons

Abstract

The K^+ \to π^0 μ^+ νγ($K_{\hat{I}¼3{\hat{I}}^3}$) decay has been measured with stopped positive kaons at the KEK 12 GeV proton synchrotron. A $K_{\hat{I}¼3{\hat{I}}^3}$ sample containing 125 events was obtained. The partial branching ratio $Br(K_{\hat{I}¼3{\hat{I}}^3},E_{\hat{I}}^3>30\mathrm{MeV},\hat{I}{¸}_{\hat{I}{¼}^{+}{\hat{I}}^3}>20^{\circ })$ was found to be $[2.4\pm 0.5(stat)\pm 0.6(syst)]\times 10^{-5}$, which is in good agreement with theoretical predictions.

12 pages, 3 figures, to be published in Physics Letters B