The ATLAS discovery potential for a heavy charged Higgs boson in gg → tbH± with H± → tb

The feasibility of detecting a heavy charged Higgs boson, mH±>mt+mb, decaying in the H±→ tb channel is studied with the fast simulation of the ATLAS detector. We study the gg→H±tb production process at the LHC which together with the aforementioned decay channel leads to four b–quarks in the final state. The whole production and decay chain reads $gg\rightarrow tbH^{\pm}\rightarrow t\bar{t}b\bar{b}\rightarrow b\bar{b}b\bar{b}l\nu\bar{q}q'$. Combinatorial background is a major difficulty in this multi–jet environment but can be overcome by employing multivariate techniques in the event reconstruction. Requiring four b–tagged jets in the event helps to effectively suppress the Standard Model backgrounds but leads to no significant improvement in the discovery potential compared to analyses requiring only three b–tagged jets. This study indicates that charged Higgs bosons can be discovered at the LHC up to high masses (mH±>400 GeV) in the case of large tanβ. Keywords: charged Higgs; MSSMPACS: 14.80.Cp – 12.60.Jv – 11.10.Kk