  We take the first steps towards an entirely on-shell description of the
bosonic electroweak sector of the Standard Model. We write down on-shell three
particle amplitudes consistent with Poincare' invariance and little group
covariance. Tree-level, four particle amplitudes are determined by demanding
consistent factorization on all poles and correct UV behaviour. We present
expressions for these $2\rightarrow 2$ scattering amplitudes using massive
spinor helicity variables. We show that on-shell consistency conditions suffice
to derive relations between the masses of the $W^\pm, Z$, the Weinberg angle
and the couplings. This provides a completely on-shell description of the Higgs
mechanism without any reference to the vacuum expectation value of the Higgs
field.
