The composite twin Higgs scenario

Riccardo Barbieri,Andrea Wulzer,Riccardo Rattazzi,Davide Greco

doi:10.1007/jhep08(2015)161

Abstract

Based on an explicit model, we propose and discuss the generic features of a possible implementation of the Twin Higgs program in the context of composite Higgs models. We find that the Twin Higgs quadratic divergence cancellation argument can be uplifted to a genuine protection of the Higgs potential, based on symmetries and selection rules, but only under certain conditions which are not fulfilled in some of the existing models. We also find that a viable scenario, not plagued by a massless Twin Photon, can be obtained by not gauging the Twin Hypercharge and taking this as the only source of Twin Symmetry breaking at a very high scale.

Highlights

Based on an explicit model, we propose and discuss the generic features of a possible implementation of the Twin Higgs program in the context of composite Higgs models
We find that the Twin Higgs quadratic divergence cancellation argument can be uplifted to a genuine protection of the Higgs potential, based on symmetries and selection rules, but only under certain conditions which are not fulfilled in some of the existing models
The relevant global symmetry group of the CS is SO(8), which gets spontaneously broken to an SO(7) subgroup delivering 7 Goldstone Bosons in the 7 of the unbroken SO(7), out of which only the Higgs boson will survive as a physical particle

Summary

The gauge sector

Aside from the Higgs, the EW bosons and the Twin W ’s, extra massive resonances are present, originating as bound states of the CS. What is remarkable and non-generic in eq (2.11) is that for g2 exactly equal to g2 the sin and cos terms sum up to 1 and the potential becomes an irrelevant shift of the vacuum energy This result is compatible with the original Twin Higgs argument [3], according to which the quadratically divergent contributions to the Higgs potential, of order g2f 2Λ2/16π2, cancel in the Twin-symmetric limit g = g. One might expect that in some situations the quadratic divergence might cancel in the low-energy theory, but still large finite contributions arise in the complete models making the Twin Higgs cancellation ineffective. Twin Parity is broken by the Hypercharge and in the Higgs potential we find an unsuppressed g12 contribution of the form

The fermionic sector

Electroweak symmetry breaking

Conclusions

B The composite multiplets