  We present a new probe of strongly coupled electroweak symmetry breaking at
the 14 TeV LHC by measuring a phase shift in the event distribution as a
function of the decay azimuthal angles in massive gauge boson scattering. A
large phase shift arises from an interference effect between the strongly
interacting longitudinal modes and the transverse modes of the gauge bosons. We
find that even very broad resonances of masses up to 900 GeV can be probed at
3$\sigma$ significance with a 3000 fb$^{-1}$ run of the LHC by using this
technique. We also present the estimated reach for a future 50 TeV
proton-proton collider.
