Characterizing a benchmark scenario for heavy Higgs boson searches in the Georgi-Machacek model

TL;DR

This paper analyzes the H5plane benchmark scenario in the Georgi-Machacek model, assessing its compatibility with LHC data, exploring Higgs boson line shape interference effects, and providing decay predictions to aid future searches.

Contribution

It provides a detailed characterization of the H5plane benchmark, including constraints, interference effects, and decay predictions, to support heavy Higgs boson searches at the LHC.

Findings

H5plane benchmark is compatible with 125 GeV Higgs measurements.

Neutral heavy Higgs lineshapes overlap and interfere in certain regions.

Decay branching ratios of additional heavy Higgs bosons are computed.

Abstract

The Georgi-Machacek model is used to motivate and interpret LHC searches for doubly- and singly-charged Higgs bosons decaying into vector boson pairs. In this paper we study the constraints on and phenomenology of the "H5plane" benchmark scenario in the Georgi-Machacek model, which has been proposed for use in these searches. We show that the entire H5plane benchmark is compatible with the LHC measurements of the 125 GeV Higgs boson couplings. We also point out that, over much of the H5plane benchmark, the lineshapes of the two CP-even neutral heavy Higgs bosons $H$ and $H_5^0$ will overlap and interfere when produced in vector boson fusion with decays to $W^+W^-$ or $ZZ$. Finally we compute the decay branching ratios of the additional heavy Higgs bosons within the H5plane benchmark to facilitate the development of search strategies for these additional particles.