Search for the rare decay $K^+\toμ^+ν\barνν$
hep-ex
/ Authors
A. V. Artamonov, B. Bassalleck, B. Bhuyan, E. W. Blackmore, D. A. Bryman, S. Chen, I-H. Chiang, I. -A. Christidi, P. S. Cooper, M. V. Diwan
and 50 more authors
J. S. Frank, T. Fujiwara, J. Hu, J. Ives, A. O. Izmaylov, D. E. Jaffe, S. Kabe, S. H. Kettell, M. M. Khabibullin, A. N. Khotjantsev, P. Kitching, M. Kobayashi, T. K. Komatsubara, A. Konaka, Yu. G. Kudenko, L. G. Landsberg, B. Lewis, K. K. Li, L. S. Littenberg, J. A. Macdonald, J. Mildenberger, O. V. Mineev, M. Miyajima
/ Abstract
Evidence of the $K^+\toμ^+ν\barνν$ 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 $K^+\toμ^+ν_μγ$. An upper limit on the decay rate $Γ(K^+\toμ^+ν\barνν)< 2.4\times 10^{-6}Γ(K^+\to all)$ 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 $μ^+$ spectrum.