Abstract
A Lagrangian of electroweak interactions without Higgs is used to study the contributions of quarks and leptons to the masses of the W and the Z bosons. It is shown that the
SU(2)×U(1)
symmetry is broken by both fermion masses and axial-vector components of the intermediate bosons. The masses of the W and the Z bosons are obtained to be (m^{2}_{W}={1\over2}g^{2}m^{2}_{t}) and (m^{2}_{Z}=\rho m^{2}_{W}/cos^{2}\theta_{W}) with (\rho\simeq 1). Two fixed gauge fixing terms for W and Z boson fields are derived respectively. A coupling between photon and Z boson is predicted. Massive neutrinos are required.