A Scalar Boson as a Messenger of New Physics

TL;DR

This paper explores how a light scalar boson could serve as a messenger of new physics beyond the Standard Model, with detectable signals at the LHC even if the new physics scale is several TeV.

Contribution

It proposes that a light scalar boson can produce observable diphoton and four-lepton events at the LHC, providing a new way to detect physics beyond the Standard Model.

Findings

Large cross sections for diphoton and four-lepton events at the LHC.

Detectability of new physics signals even if the cutoff scale is several TeV.

Abstract

Quantum corrections generate a quadratically divergent mass term for the Higgs boson in the Standard Model. Thus, if the Higgs boson has a mass of order 100 GeV, it implies the presence of a cut-off of the theory around TeV scale, and some particles associated with the new physics may appear around the cut-off scale $\Lambda$. However, if $\Lambda$ is several TeV, it may be difficult to find such particles at the LHC. In this paper, we consider a situation in which the new physics provides relatively light particles compared with the scale $\Lambda$. In such a situation, we show that diphoton event and four lepton event by the decay of the Higgs and/or a new particle have naturally large cross section, and LHC may test the new physics in a considerably broad parameter region even if $\Lambda$ is several TeV.