Search for the rare decay $K^{+}\to \hat{I}{¼}^{+}\hat{I}½\bar{\hat{I}}½\hat{I}½$

Abstract

Evidence of the $K^{+}\to \hat{I}{¼}^{+}\hat{I}½\bar{\hat{I}}½\hat{I}½$ decay was searched for using E949 experimental data with an exposure of $1.70\times 10^{12}$ stopped kaons. The data sample is dominated by the backgrond process $K^{+}\to \hat{I}{¼}^{+}\hat{I}{½}_{\hat{I}}¼{\hat{I}}^3$. An upper limit on the decay rate $\hat{I}“(K^{+}\to \hat{I}{¼}^{+}\hat{I}½\bar{\hat{I}}½\hat{I}½)<2.4\times 10^{-6}\hat{I}“(K^{+}\to all)$ at 90% confidence level was set assuming the Standard Model muon spectrum. The data are presented in such a way as to allow calculation of rates for any assumed $\hat{I}{¼}^{+}$ spectrum.

7 pages, 5 figures