Effective weak mixing angle in the MSSM - art. no. 015019

The predictions of the MSSM are discussed in the light of recent LEP and SL D precision data. The full supersymmetric one loop corrections to the effec tive weak mixing angle, experimentally determined in LEP and SLD experiment s, are considered. It is demonstrated, both analytically and numerically, t hat potentially dangerous, large logarithmic sparticle corrections are canc elled. The relative difference factor Delta k between the mixing angle defi ned as a ratio of couplings and the experimentally obtained angle is discus sed. It is found that Delta k is dominated by the oblique corrections, whil e the nonoblique overall supersymmetric EW and SQCD corrections are negligi ble. The comparison of the MSSM with radiative electroweak symmetry breakin g to the LEP + SLD precision data indicates that rather large values of the soft breaking parameter M-1/2 in the region greater than 500 GeV are prefe rred.