Probing the Higgs self-coupling through double Higgs production in vector boson scattering at the LHC

Ernesto Arganda,Claudia Garcia-Garcia,Maria Jose Herrero

doi:10.1016/j.nuclphysb.2019.114687

Abstract

In this work we explore the sensitivity to the Higgs self-coupling λ in the production of two Higgs bosons via vector boson scattering at the LHC. Although these production channels, concretely W+W−→HH and ZZ→HH, have lower rates than gluon-gluon fusion, they benefit from being tree level processes, being independent of top physics and having very distinctive kinematics that allow us to obtain very clean experimental signatures. This makes them competitive channels concerning the sensitivity to the Higgs self-coupling. In order to give predictions for the sensitivity to this coupling, we first study the role of λ at the subprocess level, both in and beyond the Standard Model, to move afterwards to the LHC scenario. We characterize the pp→HHjj case first and then provide quantitative results for the values of λ that can be probed at the LHC in vector boson scattering processes after considering the Higgs boson decays. We focus mainly on pp→bb¯bb¯jj, since it has the largest signal rates, and also comment on the potential of other channels, such as pp→bb¯γγjj, as they lead to cleaner, although smaller, signals. Our whole study is performed for a center of mass energy of s=14TeV and for various future expected LHC luminosities.

Highlights

The observation of the Higgs boson by the ATLAS and CMS experiments [1,2] in 2012 confirmed the prediction of the last particle of the Standard Model (SM) of fundamental interactions. this discovery allowed us to answer many important and well established questions about elementary particle physics, it posed a lot of new mysteries concerning the scalar sector of the SM.One of these mysteries is that of the true value of the Higgs self-coupling λ, involved in trilinear and quartic Higgs self-interactions, and its relation to other parameters of the SM
Including the extra 1/s suppression factor to compute the cross section from the squared amplitude one obtains the energy dependence seen in Fig. 3, where we present the contribution of each diagram to the total cross sections of W +W − → H H and ZZ → H H in the SM, as well as the sum of the contact, t -channel and u-channel diagrams, (c + t + u), and the total cross section taking all diagrams into account
We have studied some relevant distributions for the signal cross section that we have found give the most efficient access to the vector boson scattering (VBS) configuration in pp → H Hjj events: distributions with Mjj, ηjj and MH H

Summary

Introduction

The observation of the Higgs boson by the ATLAS and CMS experiments [1,2] in 2012 confirmed the prediction of the last particle of the Standard Model (SM) of fundamental interactions This discovery allowed us to answer many important and well established questions about elementary particle physics, it posed a lot of new mysteries concerning the scalar sector of the SM. One of these mysteries is that of the true value of the Higgs self-coupling λ, involved in trilinear and quartic Higgs self-interactions, and its relation to other parameters of the SM. Understanding and testing experimentally the relation between λ and the Higgs boson mass, mH , will provide an excellent insight into the real nature of the Higgs particle. The value of the Higgs selfcoupling has not been established yet with precision at colliders, but there is (and will be in the future) a very intense experimental program focused on the realization of this measurement (for a review, see for instance [7,8,9,10,11])

Objectives

Findings

Discussion

Conclusion