First observation of the decay K+ -> e+ nu_e mu+ mu-
Phys. Rev. D 73, 037101
Experiment 865 at the Brookhaven AGS has observed the decay K+-->e+nueµ+µ-. The branching ratio extracted is (1.72±0.37(stat)±0.17(syst)±0.19(model))×10-8 where the third term in the error results from the use of a model to extrapolate into a kinematic region dominated by background.
Cite article as:
. E865 Collaboration, "First observation of the decay K+ -> e+ nu_e mu+ mu-", Phys. Rev. D 73, 037101 (2006)