Search for the Standard Model Higgs boson produced by vector boson fusion in the bottom quark pair decay channel and real-time avour tagging selection with the ATLAS detector.

The engines used for High Energy Physics investigations are colliders: particle accelerators that rely on collisions between beams of particles for their searches. The ATLAS experiment is a general-purpose experiment that, analysing the products of these collisions, covers a broad physics programme, with the main focus being on rare and low cross section processes. Amidst these physics phenomena, the Higgs boson represents interesting a topic of investigation. This thesis work focuses on the study of the Higgs boson decay to bottom quarks, in particular in the VBF production mechanism: an extremely challenging search due to the overwhelming multi-jet backgrounds and complex jet reconstruction, calibration and identification of b-jets typical of fully hadronic final states. The b-jet triggers provide the capability to correctly identify and discriminate particles and/or jets stemming from differently flavoured quarks at online level, providing an extremely power tool to reduce the QCD background. At first, the analysis of the data collected during the 2012 LHC operations will be showed. This analysis showed that such a channel could indeed be studied, despite the huge amount of combinatorial background plaguing the event selection. Then, the analysis of the data collected during the 2016 LHC operations will be illustrated. Since the b-jet trigger is a crucial ingredient for this analysis a section will be devoted to the description of the ATLAS trigger system with a particular focus on b-jet triggers and my role as coordinator of this trigger signature.