Higgs pair production at a linear e+e- collider in models with large extra dimensions

TL;DR

This paper derives the cross section for Higgs pair production at a linear e+e- collider within large extra dimension models, demonstrating its potential to reveal spin-2 KK gravitons through characteristic angular distributions.

Contribution

It provides a new formula for Higgs pair production cross section in large extra dimension models and analyzes its measurability and spin-2 nature at future colliders.

Findings

Higgs pair production has no Standard Model background.

Angular distribution reveals spin-2 nature of KK gravitons.

Measurement feasible at high-energy linear colliders.

Abstract

In this paper, we will derive the cross section formula for the Higgs pair production at a linear $e^+e^-$ collider in models with large extra dimensions and study the feasibility of its measurement through realistic Monte Carlo simulations. Since the process has essentially no Standard Model background, once produced, it will provide us with a very clean signature of physics beyond the Standard Model. Moreover, since the final state particles are spinless, the spin 2 of the intermediate virtual KK gravitons has to be conserved by the orbital angular momentum of the Higgs pair. This results in a very characteristic angular distribution of the final states. Taking into account finite detector acceptance and resolutions as well as initial state radiation and beamstrahlung, we demonstrate in this paper that, given a sufficiently high center of mass energy, the angular distribution of the Higgs pair is indeed measurable at the linear collider and will allow us to prove the spin 2 nature of the KK gravitons exchanged in the s-channel.