Electroweak Chiral Lagrangians and γγ→ Zₗ Zₗ, Wₗ+ Wₗ- at One Loop

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In these proceedings we discuss our recent work on γγ→ W+ₗ W-ₗ and γγ→ Zₗ Zₗ within the framework of Electroweak Chiral Lagrangians with a light Higgs. These observables are good candidates to provide indications of physics beyond the Standard Model and can complement other analyses and global fits. Making use of the equivalence theorem, we have performed the computation up to the next-to-leading order in the chiral expansion, i.e., including one-loop corrections and the full set of possible counterterms allowed at that order in the low-energy effective field theory. The one-loop amplitudes turn out to have a extremely simple structure and they are ultraviolet finite. Thus, the relevant combinations of higher order chiral couplings cγʳ and (a₁ʳ-a₂ʳ+a₃ʳ) do not run. We also identify an additional set of observables that depend on these same parameters, which can be use to complement the γγ analysis through a global fit.