Uncovering the charming Higgs at the LHC

Ian Lewis,Jared Schmitthenner

doi:10.1007/jhep06(2012)072

Abstract

We study the observability of the Higgs boson in the "charming Higgs" model. In this model the Higgs boson primarily undergoes a cascade decay to four charm quarks via light intermediate pseudoscalars. Such a decay allows the Higgs boson to escape the most stringent LEP bounds on the Standard Model Higgs boson mass. If the light pseudoscalars are sufficiently light they become highly boosted and their decay products collimated into jets. We show that by using jet substructure techniques, this model is potentially observable at the LHC. For a Higgs boson mass of 100 GeV and light pseudoscalar mass of 12 GeV, we find a signal significance of 3.8 sigma with a luminosity of 30 fb^-1 and that a 5 sigma significance can be obtained with 50 fb^-1 of luminosity at the 14 TeV LHC.

Highlights

JHEP06(2012)072 for pseudoscalar masses above the bottom quark threshold
In this model the Higgs boson primarily undergoes a cascade decay to four charm quarks via light intermediate pseudoscalars. Such a decay allows the Higgs boson to escape the most stringent LEP bounds on the Standard Model Higgs boson mass
We show that by using jet substructure techniques, this model is potentially observable at the LHC

Summary

Simplified model

In the models of interest [24, 26], the Higgs boson arises as a pseudo-Goldstone boson (pGB) of an approximate global symmetry. The pseudoscalar has derivative couplings to the SM-like Higgs boson, h: L. where vEW = 174 GeV is the electroweak breaking scale, and f is a global symmetry breaking scale. For f values on the order of the electroweak breaking scale, h will dominantly decay to two η’s. If f = 350–400 GeV and the Higgs boson mass, mh, is around the Z-mass, the branching ratio of h to 2η is 80–90% and h to bb is 10–20%, consistent with the LEP bounds [24, 26]. In the so-called “charming Higgs” model [26], the η coupling to bottom quarks is suppressed by higher order operators. Throughout the rest of this paper we take the branching ratios of the Higgs boson BR(h → ηη) = 1 and pseudoscalar BR(η → cc) = 1. The signal cross sections can be scaled

Signal and background

14 TeV LHC Signal

14 TeV LHC Second hardest jet

14 TeV LHC 1 Second Hardest Jet

14 TeV LHC Second Hardest Jet

Conclusions