Search for Higgs Boson Pair Production in the Bb̅ Τ+ Τ- Decay Channel : With the CMS Detector at the LHC

This thesis presents innovative contributions to the CMS experiment in the new trigger system for the restart of the LHC collisions in Run II, as well as original analysis methods and important results that led to official publications of the Collaboration. The author's novel reconstruction algorithms, deployed on the Field-Programmable Gate Arrays of the new CMS trigger architecture, have brought a gain of over a factor 2 in efficiency for the identification of tau leptons, with a very significant impact on important H boson measurements, such as its decays to tau lepton pairs and the search for H boson pair production. He also describes a novel analysis of HH → bb tautau, a high priority physics topic in a difficult channel. The original strategy, optimisation of event categories, and the control of the background have made the result one of the most sensitive concerning the self-coupling of the Higgs boson among all possible channels at the LHC. Front Matter ....Pages i-xvi Preamble (Luca Cadamuro)....Pages 1-6 Introduction to Higgs Boson Pair Production (Luca Cadamuro)....Pages 7-49 Experimental Apparatus (Luca Cadamuro)....Pages 51-83 The L1 Open image in new window Trigger (Luca Cadamuro)....Pages 85-127 Event Selection and Categorization (Luca Cadamuro)....Pages 129-180 Modelling of Physics Processes (Luca Cadamuro)....Pages 181-205 Results on Open image in new window (Luca Cadamuro)....Pages 207-241 Future Prospects for Open image in new window Searches (Luca Cadamuro)....Pages 243-257 Conclusions (Luca Cadamuro)....Pages 259-260 Back Matter ....Pages 261-273