Eur. Phys. J. C (2014) 74: 2822
https://doi.org/10.1140/epjc/s10052-014-2822-6

Regular Article - Theoretical Physics

The effect of composite resonances on Higgs decay into two photons

Centro Científico-Tecnológico de Valparaíso, Universidad Técnica Federico Santa María, Casilla 110-V, Valparaíso, Chile

^* e-mail: antonio.carcamo@usm.cl

Received: 8 October 2013
Accepted: 14 March 2014
Published online: 10 April 2014

Abstract

In scenarios of strongly coupled electroweak symmetry breaking, heavy composite particles of different spin and parity may arise and cause observable effects on signals that appear at loop levels. The recently observed process of Higgs to at the LHC is one of such signals. We study the new constraints that are imposed on composite models from , together with the existing constraints from the high precision electroweak tests. We use an effective chiral Lagrangian to describe the effective theory that contains the Standard Model spectrum and the extra composites below the electroweak scale. Considering the effective theory cutoff at , consistency with the and parameters and the newly observed can be found for a rather restricted range of masses of vector and axial-vector composites from 1.5 to 1.7 and 1.8 to 1.9 TeV, respectively, and only provided a non-standard kinetic mixing between the and fields is included.