Probing Quartic Higgs Self-Interaction

TL;DR

This paper investigates the potential to measure the quartic Higgs self-interaction at future colliders through di-Higgs production processes, analyzing one-loop effects and collider sensitivities.

Contribution

It introduces a method to probe the quartic Higgs coupling via di-Higgs production at colliders, including renormalization effects and combined channel analysis for improved sensitivity.

Findings

ILC can measure the quartic Higgs coupling with about 20-25% precision.

Combination of di-Higgs production channels enhances collider sensitivity.

The analysis accounts for renormalization scheme dependence of the cubic Higgs coupling.

Abstract

The Higgs self-interactions play a crucial role for exploring the underlying mechanism of electroweak symmetry breaking and the nature of the phase transition involved. In this article, we propose to probe the quartic Higgs self-interaction at lepton and hadron colliders, via the di-Higgs productions. We analyze the contributions of the quartic Higgs coupling, including the renormalization of the cubic Higgs coupling and the modification of the $VVhh$ form factor, to the vector-boson-fusion and the vector-boson associated di-Higgs productions at one-loop level. Such an effect is independent of the choice of gauge-fixing, if the quartic Higgs coupling is decoupled from the other ones in the contexts considered. Notably, a combination of these two di-Higgs productions is important for optimizing the collider sensitivities to probe the quartic Higgs coupling. With this guideline, we explore the ILC and CLIC sensitivities, and find that the ILC has a potential to measure the quartic Higgs coupling, normalized by its SM value, with a precision of $\sim \pm 25$ (500 GeV, 4 ab$^{-1}$ + 1 TeV, 2.5 ab$^{-1}$) and $\sim \pm20$ (500 GeV, 4 ab$^{-1}$ + 1 TeV, 8 ab$^{-1}$), at $1\sigma$ C.L., after marginalizing the cubic Higgs coupling in the $\chi^2$ analysis. The dependence on the renormalization scheme of the cubic Higgs coupling is discussed.