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

## TL;DR

This paper studies the production of a radion scalar in association with a Z boson within warped extra-dimensional models, analyzing potential signals at the LHC and ILC, including mixing effects and resonant contributions from heavy gauge bosons.

## Contribution

It provides a comprehensive analysis of radion production with Z bosons in warped models, including mixing and resonance effects, and compares detection prospects at LHC and ILC.

## Key findings

- LHC can probe some parameter space regions for radion detection.
- ILC at high luminosity can cover most of the theoretically allowed parameter space.
- High-precision Higgs coupling measurements complement radion searches.

## Abstract

The radion scalar field might be the lightest new particle predicted by extra-dimensional extensions of the Standard Model. It could thus lead to the first signatures of new physics at the LHC collider. We perform a complete study of the radion production in association with the Z gauge boson in the custodially protected warped model with a brane-localised Higgs boson addressing the gauge hierarchy problem. Radion-Higgs mixing effects are present. Such a radion production receives possibly resonant contributions from the Kaluza-Klein excitations of the Z boson as well as the extra neutral gauge boson (Z'). All the exchange and mixing effects induced by those heavy bosons are taken into account in the radion coupling and rate calculations. The investigation of the considered radion production at LHC allows to be sensitive to some parts of the parameter space but only the ILC program at high luminosity would cover most of the theoretically allowed parameter space via the studied reaction. Complementary tests of the same theoretical parameters can be realised through the high accuracy measurements of the Higgs couplings at ILC. The generic sensitivity limits on the rates discussed for the LHC and ILC potential reach can be applied to the searches for other (light) exotic scalar bosons.