Coupling WW, ZZ unitarized amplitudes to γγ in the TeV region

We define and calculate helicity partial-wave amplitudes for processes linking the Electroweak Symmetry Breaking Sector (EWSBS) to gamma gamma, employing (to NLO) the Higgs-EFT (HEFT) extension of the Standard Model and the Equivalence Theorem, while neglecting all particle masses. The resulting amplitudes can be useful in the energy regime (500 GeV-3 TeV). We also deal with their unitarization so that resonances of the EWSBS can simultaneously be described in the.. initial or final states. Our resulting amplitudes satisfy unitarity, perturbatively in a, but for all s values. In this way we improve on the HEFT that fails as interactions become stronger with growing s and we provide a natural framework for the decay of dynamically generated resonances into WW, ZZ and gamma gamma pairs.