The STU formalism of Peskin and Takeuchi is an elegant method for encoding
the measurable effects of new physics which couples to light fermions
dominantly through its effects on electroweak boson propagation. However, this
formalism cannot handle the case where the scale of new physics is not much
larger than the weak scale. In this case three new parameters (V, W and X) are
required. We perform a global fit to precision electroweak data for these six
parameters. Our results differ from what is found for just STU. In particular
we find that the preference for S < 0 is not maintained.
Authors
Burgess CP; Godfrey S; Konig H; London D; Maksymyk I