A system for the configuration of front-end-electronics for CMS subdetectors and studies on the observability of a MSSM Higgs boson in the 4-b final-state

Two aspects of the CMS experiment were covered in this thesis: the Front-End electronics configuration and the observability of the A/H Higgs bosons in the four-b final state. A Front-End electronics configuration system for the CMS subdetectors was developed and was tested with great success. It has been integrated in the DCS framework, but can be also easily adapted for use within another framework as the Run Control and Monitoring System. The study of the observability of the A/H Higgs in four-b final state pointed out the importance of an efficient b-tagging with a low mistagging probability and of an accurate jet reconstruction. The irreducible backgrounds-events with four b-jets-represent only 12% of the backgrounds which pass all selection cuts. 72% of the backgrounds have one or two mistagged jets. For a pseudoscalar Higgs mass mA = 400 GeV, a significance of at least 5 . σ is expected for tan β > 25 (trigger efficiency included). The significance diminishes with the A mass because of the cross-section decrease: for mA = 600 GeV, a 5 . σ significance is reached for tan β = 35. Those significances include only statistical errors. For mA = 600 GeV and tan β = 35 -corresponding to a significance of 5 . σ- the signal over backgrounds ratio S/N is only 1.04%. Therefore, this study lead to the conclusion that this channel does not extend the (mA, tan β) discovery region already covered by the H/A → ττ mode. The four-b channel can still be used as a confirmation in case of a Higgs discovery at high tan β value (tan β >or sim 25) and also to calculate, in combination with the ττ channel, the A/H Higgs boson coupling with bb pairs. (orig.)