Department of
Physics and Astronomy
Precision Electroweak Tests
The standard model
is a mathematically consistent renormalizable field theory
which predicts or is consistent with all known aspects
of the elementary particles and their interactions
over an enormous range of probes and scales.
In particular,
it is now clear that, with the possible exception
of the Higgs sector,
the standard electroweak model is the
correct theory of nature to an excellent approximation down
to a distance scale of 
cm.
Precision neutral current, charged current, and Z and W
pole experiments have established or supported the framework
of renormalizable field theory and of gauge theories;
have established the 
gauge group; have
confirmed the fermion representations; have successfully
confirmed the predictions for
the existence, masses, and properties of the
electroweak gauge bosons;
have confirmed or led to successful predictions for higher
order effects such as the running of the electromagnetic fine
structure constant, the top quark mass, and the strong
coupling constant; have searched for and excluded large
regions of parameter space associated with alternative
symmetry breaking mechanisms and other possible new
physics beyond the standard model; and have shown that
the strong and electroweak coupling constants are consistent
with supersymmetric grand unification.
Scientists at the University of Pennsylvania have long been involved with many aspects of this program. Experiments include neutrino scattering experiments at Fermilab and Brookhaven and the direct discovery of the top quark at Fermilab. Theoretical and phenomenological efforts include a long-term ongoing project to systematically collect all precision data and apply the best possible theoretical analysis for testing the standard model, determining its parameters, and searching for new physics.