Precision flavour analyses for the era of the high-luminosity LHC and beyond

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Particle Physics investigates the fundamental constituents of matter and the nature of their interactions. Our present understanding of these constituents and interactions is contained in a rigorous theoretical description: the Standard Model of Particle Physics. While the Standard Model is very successful in describing most phenomena to date, it has a number of shortcomings and fails to explain a variety of observations. It is therefore generally accepted that the Standard Model needs replacing, but the overarching question is: what is the replacement?My research contributes to answering this question by investigating the rare decay of a so-called bottom quark into a strange quark with the emission of an electron-positron pair, a decay of the type b->sl+l-. This type of decay is a promising candidate to change our understanding of Nature and to revise the Standard Model due to intriguing and long-standing discrepancies between theoretical predictions and experimental measurements. UK researchers in experimental particle physics are leading the effort to improve such measurements.. The two quarks species or "flavours" involved in the decay are absent in everyday life,but they are abundantly produced in highly-energetic particle collisions at the world's largest Particle Physics experiment, CERN's Large Hadron Collider. The Large Hadron Collider experiments continue to measure these decays with unprecedented precision.Our current theoretical description of the b->sl+l- decay comes with large and hard-to-quantify uncertainties. These hamper a clear and unambiguous interpretation of the present discrepancies between theory and ever more precise experiment. Are they a first genuine sign of interactions beyond the SM? Are they the imprint of energetic yet-undiscovered constituents of matter? To answer these questions, it is mandatory that the theory side improves in lockstep with the experimental endeavours. My research will improve the theory side by reducing the theoretical uncertainties to the extent that a discovery of new types of matter or interactions in the decay can either be confirmed or refuted with present data. To this end, I will use a variety of mathematical and statistical tools, and I will use data on other types of bottom quark decay to hone the accuracy of my predictions.