Flavor violation in supersymmetric SU(5) GUT at large tan β -: art. no. 055006

We study flavor violation in the general SUSY SU(5) GUT assuming all the third generation Yukawa couplings to be due to the renormalizable physics above GUT scale. At large tan beta, as suggested by Yukawa unification in SU(5), sizable flavor violation in the left (right) slepton (down squark) sector can be induced in nonminimal models due to renormalization effects of down type Yukawa couplings between GUT and Planck scales, in addition to the flavor violation in the right slepton sector. The new flavor physics contribution to K-(K) over bar, B-(B) over bar mixing is small but might be of phenomenological interest in the case of b --> s gamma. The sign of the latter contribution is the same as the sign of the dominant chargino contribution, thus making the constraints on the SUSY scale coming from b --> s gamma somewhat more restrictive. The most important feature of the considered scenario is the large rate of lepton flavor violation. Given the present experimental constraints, the mu --> e gamma and mu -e conversion branching ratios are above the sensitivity of the planned experiments unless the SUSY scale is pushed above one TeV.