GLUON AND GLUINO PENGUIN DIAGRAMS AND THE CHARMLESS DECAYS OF THE B-QUARK - ART. NO. 073006

Gluon mediated exclusive hadronic decays of b quarks are studied withi n the standard model (SM) and the constrained minimally supersymmetric standard model (MSSM). For all allowed regions of the MSSM parameter space (A, tan beta,m(0),m(1/2)) the Denguin magnetic dipole form facto r F-2(R) is dominant over the electric monopole and can be larger than the magnetic dipole form factor of the SM. However, overall the SM el ectric monopole decay amplitude F-1(L) dominates the decay rate. The M SSM penguin contributions to the free quark decay rate approach the 10 % level for those regions of parameter space close to the highest allo wed values of tan beta (similar to 55) for which the gluino is light ( m((g) over bar)approximate to 360 GeV) and lies within the range of th e six (d) over tilde squark masses. In these regions the supersymmetri c box amplitudes are negligible. The MSSM phases change very little ov er the allowed parameter space and can lead to significant interferenc e with the SM amplitudes. [S0556-2821(98)00919-9]