Higgs friends and counterfeits at hadron colliders

TL;DR

This paper explores hypothetical particles called Higgs friends and counterfeits that mimic Higgs signals at colliders, emphasizing how their discovery could reveal new colored or electroweak states and proposing methods to distinguish them from true Higgs bosons.

Contribution

It introduces the concepts of Higgs friends and counterfeits, analyzing their production, decay channels, and how to differentiate them from the Standard Model Higgs at the LHC.

Findings

Higgs counterfeits can produce signals similar to the Higgs but do not cause electroweak symmetry breaking.

Higgs friends may have larger production cross sections in diboson channels than the Higgs.

Vector boson fusion is a key channel to distinguish genuine Higgs from counterfeit or friend particles.

Abstract

We consider the possibility of "Higgs counterfeits" - scalars that can be produced with cross sections comparable to the SM Higgs, and which decay with identical relative observable branching ratios, but which are nonetheless not responsible for electroweak symmetry breaking. We also consider a related scenario involving "Higgs friends," fields similarly produced through gg fusion processes, which would be discovered through diboson channels WW, ZZ, gamma gamma, or even gamma Z, potentially with larger cross sections times branching ratios than for the Higgs. The discovery of either a Higgs friend or a Higgs counterfeit, rather than directly pointing towards the origin of the weak scale, would indicate the presence of new colored fields necessary for the sizable production cross section (and possibly new colorless but electroweakly charged states as well, in the case of the diboson decays of a Higgs friend). These particles could easily be confused for an ordinary Higgs, perhaps with an additional generation to explain the different cross section, and we emphasize the importance of vector boson fusion as a channel to distinguish a Higgs counterfeit from a true Higgs. Such fields would naturally be expected in scenarios with "effective Z's," where heavy states charged under the SM produce effective charges for SM fields under a new gauge force. We discuss the prospects for discovery of Higgs counterfeits, Higgs friends, and associated charged fields at the LHC.