THE SIGN OF S FROM ELECTROWEAK RADIATIVE-CORRECTIONS

We consider radiative corrections to the parameter S characterizing "oblique" corrections to electroweak interactions from representations of electroweak interactions which preserve a custodial SU (2) symmetry. Our primary goal is to demonstrate that the contribution to S can take either sign. We consider two general cases, one with scalars and one with fermions. The most interesting example is scalar representations, which we will show can quite generally generate a negative contribution to S. For the class of fermion representations we consider, S can also be negative, although larger mass splittings between custodial SU (2) representations are required.