A global fit to extended oblique parameters
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. A global fit to precision electroweak data for these six parameters is performed. Our results differ from what is found for just STU. In particular we find that the preference for S<0 is no longer statistically significant.
|Journal||Physics Letters B|
Burgess, C.P., Godfrey, S, König, H. (Heinz), London, D. (David), & Maksymyk, I. (Ivan). (1994). A global fit to extended oblique parameters. Physics Letters B, 326(3-4), 276–281. doi:10.1016/0370-2693(94)91322-6