One-loop MSSM Contribution to the Weak Magnetic Dipole Moments of Heavy Fermions

The MSSM predictions at the one-loop level for the weak-magnetic dipole moments of the $\tau$ lepton and the $b$ quark are analysed. The entire supersymmetric parameter space is scanned with the usual GUT constraint and common squark and slepton mass parameters. The real part of $a^W_\tau$ is dominated by the chargino contribution, being the same order as the SM one or even larger in the high $\tan\beta$ region whereas the imaginary part, due to Higgs boson diagrams, is negligible compared to the SM value. The real part of $a^W_b$ is controlled mainly by charginos and also by gluinos, when themixing in the bottom squark sector is large, to yield, for high $\tan\beta$, a contribution one order of magnitude larger than the pure electroweak SMvalue but a factor five smaller than the standard QCD contribution. The imaginary part of $a^W_b$ is the same order as in the SM