One-loop corrections to the Higgs self-couplings in the singlet extension

TL;DR

This paper calculates one-loop radiative corrections to the Higgs self-couplings in a singlet extension model, revealing significant deviations from the Standard Model predictions, with implications for collider experiments.

Contribution

It provides the first detailed one-loop level analysis of the triple Higgs coupling and decay rates in the singlet scalar extension, including experimental and theoretical constraints.

Findings

Deviations in the $hhh$ coupling can reach up to 250% for certain parameters.

The decay rate of $H o hh$ is computed at one-loop level.

Constraints from $W$ boson mass measurements limit the mixing angle.

Abstract

We investigate predictions on the triple Higgs boson couplings with radiative corrections in the model with an additional real singlet scalar field. In this model, the second physical scalar state ($H$) appears in addition to the Higgs boson ($h$) with the mass 125 GeV. The $hhh$ vertex is calculated at the one-loop level, and its possible deviation from the predictions in the standard model is evaluated under various theoretical constraints. The decay rate of $H \to hh$ is also computed at the one-loop level. We also take into account the bound from the precise measurement of the $W$ boson mass, which gives the upper limit on the mixing angle $\alpha$ between two physical Higgs bosons for a given value of the mass of $H$ ($m_H^{}$). We find that the deviation in the $hhh$ coupling from the prediction in the standard model can maximally be about 250\%, 150\% and 75\% for $m_H^{}=300$, 500 and 1000 GeV, respectively, under the requirement that the cutoff scale of the model is higher than 3 TeV. We also discuss deviations from the standard model prediction in double Higgs boson production from the gluon fusion at the LHC using the one-loop corrected Higgs boson vertices.