Singlet scalars as Higgs imposters at the Large Hadron Collider

TL;DR

This paper explores how a singlet scalar could mimic the Higgs boson at the LHC by producing enhanced diphoton and Z gamma signals, potentially leading to false Higgs identification.

Contribution

It introduces the possibility that electroweak singlet scalars can produce Higgs-like signals through loop-induced couplings, challenging standard Higgs identification methods.

Findings

Enhanced diphoton and Z gamma decay widths compared to the Standard Model Higgs.

Singlet scalars can produce observable signals above WW threshold.

Potential for misidentifying singlet scalars as Higgs bosons in collider experiments.

Abstract

An electroweak singlet scalar can couple to pairs of vector bosons through loop-induced dimension five operators. Compared to a Standard Model Higgs boson, the singlet decay widths in the diphotons and Z gamma channels are generically enhanced, while decays into massive final states like WW and ZZ are kinematically disfavored. The overall event rates into gamma gamma and Z gamma can exceed the Standard Model expectations by orders of magnitude. Such a singlet may appear as a resonant signal in the gamma gamma and Z gamma channels, even with a mass above the WW kinematic threshold.