REANALYSIS OF THE MASS DIFFERENCE OF B-D(0)-(B)OVER-BAR-(D)(0) WITHINTHE MINIMAL SUPERSYMMETRIC STANDARD MODEL

We present a detailed and complete calculation of the loop corrections to the mass difference Delta m(Bd)(0)/m(Bd)(0). We include charginos and scalar up quarks as well as gluinos and scalar down quarks on the relevant loop diagrams. We include the mixings of the charginos and of the scalar partners of the left and right handed quarks. We find that the gluino contribution to this quantity is important with respect to the chargino contribution only in a small part of phase space: mainly when the gluino mass is small (similar to 100 GeV) and the symmetry-b reaking parameter ms is below 300 GeV. This contribution is also impor tant for very large values of tan beta (similar to 50) irrespective of the other parameters. Otherwise, the chargino contribution dominates vastly and can be roughly as large as that of the Standard Model. We a lso present the contribution of the charged Higgs to the mass differen ce Delta m(Bd)(0)/m(BD)(0) in the case m(b) tan beta much less than m( t) cot beta. This last contribution can be larger than the Standard Mo del contribution for small values of the Higgs mass and small values o f tan beta.