Natural flavour mixing in the MSSM and $\mu -->e,\gamma$

Abstract

In the absence of any additional assumption it is natural to conjecture that sizeable flavour-mixing mass entries, $\Delta m^2$, may appear in the mass matrices of the scalars of the MSSM, i.e. $\Delta m^2\sim O(m^2)$. This flavour violation can still be reconciled with the experiment if the gaugino mass, $M_{1/2}$, is large enough to yield (through the renormalization group running) a sufficiently small $\Delta m^2/m^2$ at low energy. This leads to a gaugino dominance framework (i.e. $M_{1/2}^2\gg m^2$), which permits a remarkably model--independent analysis. We study this possibility focussing our attention on the $\mu \to e,\gamma$ decay. In this way we obtain very strong and general constraints, in particular $\frac{M_{1/2}^2}{Δm} \simgt 34\ {\rm TeV}$.

6 pages, latex+sprocl.sty, 2 figures uuencoded. Based on a talk given by J.M. Moreno at the International Workshop on Elementary Particle Physics: Present and Future, Valencia (Spain) 5-9 June 1995