Observation of the Decay K- -> pi- mu+ mu- and Measurements of the Branching Ratios for K+/- -> pi+/- mu+ mu-

H. K. Park

Using data collected with the HyperCP (E871) spectrometer during the 1997 fixed-target run at Fermilab, we report the first observation of the decay K- -> pi- mu+ mu- and new measu…