2006/03/31 by J. A. Aguilar-Saavedra, Juan Antonio Aguilar–Saavedra · 2 citations
Computer Science · Physics and Astronomy · #Boson #Computational Physics and Python Applications #Higgs boson #Large Hadron Collider #Luminosity #Particle Detector Development and Performance #Particle physics theoretical and experimental studies #Quark #Standard Model (mathematical formulation) #Top quark #hep-ph
paper · pdf · doi:10.1088/1126-6708/2006/12/033
published as JHEP0612:033,2006 · LaTeX, 37 pages, 57 PS figures. Many improvements in the analysis. Final version to appear in JHEP
arxiv created 2006/11/12 · openalex publication_date 2006/12/11 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We evaluate the LHC discovery potential for a light Higgs boson in t tbar H (-> l nu b bbar b bbar jj) production, within the Standard Model and if a new Q=2/3 quark singlet T with a moderate mass exists. In the latter case, T pair production with decays T Tbar -> W+ b H tbar / H t W- bbar -> W+ b W- bbar H provides an important additional source of Higgs bosons giving the same experimental signature, and other decay modes T Tbar -> H t H tbar -> W+ b W- bbar H H, T Tbar -> Z t H tbar / H t Z tbar -> W+ b W- bbar H Z further enhance this signal. Both analyses are carried out with particle-level simulations of signals and backgrounds, including t tbar plus n=0...5 jets which constitute the main background by far. Our estimate for SM Higgs discovery in t tbar H production, 0.4 sigma significance for MH = 115 GeV and an integrated luminosity of 30 fb-1, is similar to the most recent ones by CMS which also include the full t tbar nj background. We show that, if a quark singlet with a mass mT = 500 GeV exists, the luminosity required for Higgs discovery in this final state is reduced by more than two orders of magnitude, and 5 sigma significance can be achieved already with 8 fb-1. This new Higgs signal will not be seen unless we look for it: with this aim, a new specific final state reconstruction method is presented. Finally, we consider the sensitivity to search for Q=2/3 singlets. The combination of these three decay modes allows to discover a 500 GeV quark with 7 fb-1 of luminosity.