Conceptualization, implementation, and commissioning of real-time analysis in the High Level Trigger of the LHCb experiment

LHCb is a general purpose forward detector located at the Large Hadron Collider (LHC) at CERN. Although initially optimized for the study of hadrons containing beauty quarks, the better than expected performance of the detector hardware and trigger system allowed LHCb to perform precise measurements of particle properties across practically the full range of light hadron species produced at the LHC. The abundance of these light hadron species, and the large branching ratios of many theoretically interesting decay modes, have made it mandatory for LHCb to perform a large part of its data analysis within the experiment's trigger system, that is to say in real-time. This thesis describes the conceptualization, development, and commissioning of real-time analysis in LHCb, culminating in the proof-of-concept measurements produced with the first data collected in Run~II of the LHC. It also describes mistakes made in these first real-time analyses, and their implication for the future of real-time analysis at LHCb and elsewhere.