Observability of Higgs produced with top quarks and decaying to bottom quarks

The decay, H bb, is dominant for a Standard Model Higgs boson in the mass range just above the exclusion limit of 114.4 GeV/c 2 reported by the LEP experiments. Unfortunately, an overwhelming abundance of b b events arising from more mundane sources, together with the lack of precision inherent in the reconstruction of the Higgs mass, renders this decay mode a priori undetectable in the case of direct Higgs production at the LHC. It is therefore of no small interest to investigate whether H bb can be observed in those cases where the Higgs is produced in association with other massive particles. In this note, the results of a study of Higgs bosons produced in association with top quarks and decaying via H bb are presented. The study was performed as realistically as possible by employing a full and detailed Monte Carlo simulation of the CMS detector followed by the application of trigger and reconstruction algorithms that were developed for use with real data. Important systematic effects resulting from such sources as the uncertainties in the jet energy scale and the estimated rates for correctly tagging b jets or mistagging non-b jets have been taken into account. The impact of large theoretical uncertainties in the cross sections for tt plus N jets processes due to an absence of next-to-leading order calculations is also considered.