paper

Observation of the Decay K+ --> pi+ mu+ mu-

arXiv:hep-ex/9708012 · doi:10.1103/PhysRevLett.79.4756

Abstract

We have observed the rare decay K+ --> pi+ mu+ mu- and measured the branching ratio Gamma(K+ --> pi+ mu+ mu-)/Gamma(K+ --> all) = (5.0 +/- 0.4 (stat.) +/- 0.7 (sys.) +/- 0.6 (theor.)) x 10^{-8}. We compare this result with predictions from chiral perturbation theory and estimates based on the decay K+ --> pi+ e+ e-.

9 pages, LaTeX, 2 Postscript figures. Version to be published in PRL

Observation of the Decay K+ --> pi+ mu+ mu- · wovepaper