Electroweak Chiral Lagrangian with a Light Higgs and photon photon → WL WL, ZL ZL at the One-Loop Level (8 de abril de 2014)

Descripción

The photon photon scattering into longitudinal electroweak gauge bosons can be used to discern new physics in present a future collider experiments. We take an effective field theory approach where we consider the electroweak chiral Lagrangian including a light Higgs-like scalar (ECLh) as a dynamical light field together with the would-be-Goldstone bosons associated to the electroweak symmetry breaking. This description assumes the existence of a mass gap between mh, mW, mZ and the potential new emergent resonances, setting an intermediate energy region (above mh,MW,MZ and below the resonance masses) where the use of the ECLh is the most appropriate tool to compute the relevant observables. We analyze in detail the proper chiral counting rules for the present case, the photon-photon scattering. The amplitude is computed within this effective theory framework up to next-to-leading order, i.e., up to the one-loop level (only bosonic contributions so far). The distinctive signal we found in our theoretical prediction leads to interesting implications both theoretically and experimentally. After extremely subtle cancellations the final amplitudes are UV finite, being determined by a set of renormalization group invariant combinations of effective couplings. We finally propose a joint analysis of our results for the photon-photon scattering amplitudes together with other photonic processes and electroweak precission observables for a future comparison with data. This could help to disantangle the nature of the light Higgs-like particle.

Electroweak Chiral Lagrangian with a Light Higgs and photon photon → WL WL, ZL ZL at the One-Loop Level

por Juan José Sanz Cillero (Universidad Autónoma de Madrid, Spain)

Seminar Room 1.1.1

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