Higgs Production and Decay in Models of a Warped Extra Dimension with a Bulk Higgs

TL;DR

This paper investigates Higgs production and decay in warped extra-dimensional models with a bulk Higgs, calculating key processes and analyzing how Kaluza-Klein excitations affect observable signals, with implications for electroweak constraints.

Contribution

It provides detailed calculations of Higgs production and decay rates in warped extra-dimensional models, including effects of Kaluza-Klein modes and their dependence on model parameters.

Findings

Higgs production cross section is enhanced by KK fermions.

Higgs decay rate to gamma gamma is reduced due to KK contributions.

Higgs couplings to fermions and gauge bosons are suppressed.

Abstract

Warped extra-dimension models in which the Higgs boson is allowed to propagate in the bulk of a compact AdS$_5$ space are conjectured to be dual to models featuring a partially composite Higgs boson. They offer a framework with which to investigate the implications of changing the scaling dimension of the Higgs operator, which can be used to reduce the constraints from electroweak precision data. In the context of such models, we calculate the cross section for Higgs production in gluon fusion and the $H\to\gamma\gamma$ decay rate and show that they are finite (at one-loop order) as a consequence of gauge invariance. The extended scalar sector comprising the Kaluza-Klein excitations of the Standard Model scalars is constructed in detail. The largest effects are due to virtual KK fermions, whose contributions to the cross section and decay rate introduce a quadratic sensitivity to the maximum allowed value $y_\ast$ of the random complex entries of the 5D anarchic Yukawa matrices. We find an enhancement of the gluon-fusion cross section and a reduction of the $H\to\gamma\gamma$ rate as well as of the tree-level Higgs couplings to fermions and electroweak gauge bosons. We perform a detailed study of the correlated signal strengths for different production mechanisms and decay channels as functions of $y_\ast$, the mass scale of Kaluza-Klein resonances and the scaling dimension of the composite Higgs operator.