Scalar Production in Association with a Z Boson at LHC and ILC: the Mixed BEH-Radion Case of Warped Models

Abstract

The radion scalar field might be the lightest new particle predicted by extra-dimensional extensions of the Standard Model, thus possibly leading to the first signatures of new physics at the LHC. We perform a study of its production in association with a $Z$ boson in the custodially protected warped model with a brane-localised Higgs boson addressing the gauge hierarchy problem, with Higgs-radion mixing effects included. While the considered radion production at the LHC would constrain some parts of the parameter space, it is only the ILC program that will be able to cover a significant part of this space through the studied process. Complementary tests of the same theoretical parameters can be realised through the high accuracy measurements of the Higgs couplings at ILC.