Search for the Decay $K^+ \to π^+ ν\overlineν$

Adler, S.; Atiya, M. S.; Chiang, I-H.; Frank, J. S.; Haggerty, J. S.; Kycia, T. F.; Li, K. K.; Littenberg, L. S.; Sambamurti, A.; Stevens, A.; Strand, R. C.; Witzig, C.; Louis, W. C.; Akerib, D. S.; Ardebili, M.; Convery, M. R.; Ito, M. M.; Marlow, D. R.; McPherson, R. A.; Meyers, P. D.; Selen, M. A.; Shoemaker, F. C.; Smith, A. J. S.; Blackmore, E. W.; Bryman, D. A.; Felawka, L.; Kitching, P.; Konaka, A.; Kujala, V. A.; Kuno, Y.; Macdonald, J. A.; Nakano, T.; Numao, T.; Padley, P.; Poutissou, J-M.; Poutissou, R.; Roy, J.; Soluk, R.; Turcot, A. S.

Search for the Decay $K^+ \to π^+ ν\overlineν$

Authors

Description

An upper limit on the branching ratio for the decay $K^+ \! \rightarrow \! π^+ ν\overlineν$ is set at $2.4 \times 10^{-9}$ at the 90\% C.L. using pions in the kinematic region $214~{\rm MeV}/c < P_π< 231~{\rm MeV}/c$. An upper limit of $5.2 \times 10^{-10}$ is found on the branching ratio for decays $K^+ \! \rightarrow \! π^+ X^0$, where $X^0$ is any massless, weakly interacting neutral particle. Limits are also set for cases where $M_{X^0}>0$.
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