Large |Vub|:: a challenge for the minimal flavour violating MSSM

Under the assumption of Minimal Flavour Violation (MFV), the Unitarity Triangle (UT) can be determined by using only angle measurements and tree-level observables. In this respect, the most accurate quantities today available are sin2 beta(psi KS) vertical bar V-cb vertical bar and vertical bar V-ub vertical bar. Among the latter, vertical bar V-ub vertical bar is at present the quantity suffering from largest systematic uncertainties, given the discrepancy between the inclusive and the exclusive determinations. We show with a numerical fit how sensitively the MFV-UT determination depends on the choice Of vertical bar V-ub vertical bar. In addition, we focus on the implications of the inclusive value for vertical bar V-ub vertical bar, which favors two non-SM like solutions in the (rho) over bar - (eta) over bar - plane. We study in detail the possibility of reproducing such solutions within the MFV MSSM. Our findings indicate that the case for the MFV MSSM is in this respect quite problematic, unless the non-perturbative parameters xi and B-K are significantly different from those obtained by lattice methods. As a byproduct, we point out that scenarios with 200 GeV less than or similar to MA less than or similar to 500 GeV and tan beta similar or equal to 50 that predict a significant suppression for Delta M-s in correlation with an enhancement for BR(B-s -> mu(+) mu(-)) have to be fine-tuned in order not to violate the new combined bound on the latter decay mode from the CDF and DO collaborations. Relatively large correlated effects can however still occur for negative values of mu and large values for M-A greater than or similar to 500 GeV, increasing with increasing tan beta greater than or similar to 30.