Predictions of Electroweak Theory

• Neutral currents exist

e.g. (F&H equations 13.42, 13.43)

Neutral currents discovered 1973 at CERN.

• W± and Z0 bosons exist, with

   and   

(F&H equations 13.37, 13.38)

The W± & Z0 were discovered in 1982 at CERN.

• the top quark must exist

or else the b quark will not have full weak coupling

The top quark was discovered in 1994 by the CDF experiment at Fermilab.

Some questions about electroweak gauge theory:

• Why is it left handed? SU(2)_L!

• Why is gauge symmetry broken? M_W,M_Z>>0! Masses?
• How is unitarity violation resolved? s(WWÆWW) ~ s!