A renormalizable gauge field theory is constructed generally. A set of gauge fields is coupled in a gauge invariant way to fermion and scalar fields. These scalar fields are spontaneously broken down and acquire a vacuum expectation value. Consequently, the gauge fields become massive by means of Higgs mechanism. The particular Weinberg Salam model among many possible renormalizable theories is worked out in detail. Specific predictions on physically observable process are made. Important experiments are reviewed and analyzed. Data are tested against the predictions of Weinberg Salam model. We show W- S model is not in disagreement with experiment in the present.