Fusing vectors into scalars at high energy lepton colliders

Dario Buttazzo,Andrea Tesi,Diego Redigolo,Filippo Sala

doi:10.1007/jhep11(2018)144

Abstract

We study vector boson fusion production of new scalar singlets at high energy lepton colliders. We find that CLIC has the potential to test single production cross-sections of a few tens of attobarns in di-Higgs and di-boson final states. In models with a sizeable singlet-Higgs mixing, these values correspond to a precision in Higgs couplings of order 0.1% or better. We compare our sensitivities with those of the LHC and interpret our results in well-motivated models like the Twin Higgs, the NMSSM and axion-like particles. Looking forward to even higher energy machines, we show that the reach of muon colliders like LEMMA or MAP overcomes the one of future hadron machines like FCC-hh. We finally study the pair production of the new scalar singlets via an off-shell Higgs. This process does not vanish for small mixings and will constitute a crucial probe of models generating a first order electro-weak phase transition.

Highlights

Built at CERN [8] and/or at the muon accelerator facility at Fermilab [9]
In High Energy Lepton Colliders (HELCs) like CLIC the production cross-section for the SM Higgs will instead be dominated by the W W -fusion process, with a rate given in the high-energy limit by
In order to discuss the interplay between precision tests of the Higgs sector and the direct exploration of new physics, we focus on models where new physics is coupled to the SM Higgs sector

Summary

Introduction

Built at CERN [8] and/or at the muon accelerator facility at Fermilab [9]. Muons could be produced from p scattering on a target (MAP [9]) or e+ scattering on a target (LEMMA [10,11,12]), see refs. [12,13,14] for the attainable luminosities with these technologies. In HELCs like CLIC the production cross-section for the SM Higgs will instead be dominated by the W W -fusion process, with a rate given in the high-energy limit by By means of the W W -fusion process, HELCs can partially overcome the smaller luminosity compared to the low energy colliders and obtain a similar precision in the Higgs couplings to gauge bosons, as discussed in ref. The main question we want to address in this paper is the following: To what extent will CLIC, and HELCs in general, directly test new physics inducing deviations in the Higgs couplings to gauge bosons of a few percent or smaller?. We comment on to what extent di-boson searches at HELCs can probe the heavy mass regime of an axion-like particle that couples only to electroweak (EW) gauge bosons, a scenario which is notoriously challenging from the phenomenological point of view [25,26,27]

Objectives

Findings

Discussion

Conclusion