ΔMs/ΔMd, sin 2β and the angle γ in the presence of new ΔF=2 operators

We present formulae for the mass differences DeltaM(d) and DeltaM(s) in the (B) over bar (0)(d,s)-B-d,s(0) systems and for the CP violation parameter epsilon which are valid in minimal flavour violation models giving rise to new four-fermion DeltaF = 2 operators. Short distance contributions to DeltaM(s), DeltaM(d) and epsilon are parameterized by three real functions F-tt(s), F-tt(d), and F-tt(epsilon), respectively (F-tt(s) = F-tt(d) = F-tt(epsilon) holds only if the Standard Model (V - A) x (V - A) operators dominate). We present simple strategies involving the ratio DeltaM(s)/DeltaM(d), sin2 beta and gamma that allow to search for the effects of the new operators. We point out that their sizable contributions to the ratio DeltaM(s)/DeltaM(d) would in principle allow gamma to be larger than 90 degrees. Constraints on the functions F-tt(i) imposed by the present (and future) experimental data are also discussed. As an example we show that for large tan <(<beta>)over bar> = upsilon (2)/upsilon (1) and H+ not too heavy, F-tt(s) in the MSSM with heavy sparticles can be substantially smaller than in the SM due the charged Higgs box contributions and in particular due to the growing like tan(4) <(<beta>)over bar> contribution of the double penguin diagrams involving neutral Higgs boson exchanges. As a result the bounds on the function F-tt(s) can be violated which allows to exclude large mixing of stops. In this scenario the range of sin2 beta following from epsilon and DeltaM(d) is identical to the SM ones (0.5 < sin2<beta> < 0.8). On the other hand <gamma> following from DeltaM(s)/DeltaM(d) is lower. (C) 2001 Published by Elsevier Science B.V.