Unitary Limit on $K_L^0\to {\mu }^{+}{\mu }^{-}$ and the Top Quark Mass

Abstract

A brief overview of the recent measurements of the branching ratio of the rare $K_L^0\to {\mu }^{+}{\mu }^{-}$ decay in the context of their agreement with the Standard Model (SM) is given. It is shown that KEK result well correlates with the SM and B-physics, whereas the BNL results are in conflict with the SM with the heavy top quark.

Comments: 6 pages, LaTeX, Talk given by N.V.Mikheev at Les Rencontres de Physique de la Vallee d'Aoste: Results and Perspectives in Particle Physics, La Thuile, Italy, March 5-11, 1995