  Gluon mediated exclusive hadronic decays of b quarks are studied within 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 penguin magnetic dipole form factor F^R_2 is dominant over the
electric dipole and can be larger than the magnetic dipole form factor of the
SM. However, overall the SM electric dipole decay amplitude F^L_1 dominates the
decay rate. The MSSM penguin contributions to the free quark decay rate
approach the 10% level for those regions of parameter space close to the
highest allowed values of tan beta (~55) for which the gluino is light
(m_{\tilde{g}} \approx 360 GeV) and lies within the range of the six d-squark
masses. In these regions the supersymmetric box amplitudes are negligible. The
MSSM phases change very little over the allowed parameter space and can lead to
significant interference with the SM amplitudes.
