NEGATIVE, ANOMALY-FREE, OBLIQUE RADIATIVE-CORRECTIONS

Current electroweak precision measurements tend to prefer negative values of the oblique radiative parameters, S and T, relative to their standard-model expectations. This tendency is shown to be consistent with the existence of new colorless fermions in the anomaly-free combination of two doublets (N1,E)L and (E(c),N2)L and one singlet N3L, which are contained in some supersymmetric or E6 extensions of the standard model.