Precision flavour physics and supersymmetry

We review the salient features of a comparative study of the profile of the CKM unitarity triangle, and the resulting CP-violating phases alpha, beta and gamma in B decays, in the standard model and in several variants of the minimal supersymmetric standard model (MSSM), reported recently by us. The se theories are characterized by a single phase in the quark flavour mixing matrix and give rise to well-defined contributions in the flavour-changing -neutral-current transitions in K and B decays. We analyse the supersymmetr ic contributions to the mass differences in the B-d(O)-<(B-d(O))over bar> a nd B-s(O)-<(B-s(O))over bar> systems, Delta M-d and Delta M-s, respectively , and to the CP-violating :quantity /epsilon/ in K decays. Our analysis sho ws that the predicted ranges of beta in the standard model and in MSSM mode ls are very similar. However, precise measurements at B-factories and hadro n machines may be able to distinguish these theories in terms of the other two CP-violating phases alpha and gamma. (C) 1999 Elsevier Science B.V. All rights reserved.