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

粒子物理学研究物质的基本成分及其相互作用的本质。我们目前对这些成分和相互作用的理解包含在一个严格的理论描述中：粒子物理学的标准模型。虽然标准模型在描述迄今为止的大多数现象方面非常成功，但它有许多缺点，无法解释各种观察结果。因此，人们普遍认为标准模型需要替换，但首要的问题是：什么是替换？我的研究有助于回答这个问题，通过调查所谓的底夸克罕见的衰变到一个奇异的夸克与电子-正电子对的发射，衰变类型为b->sl+l-。这种类型的衰变很有希望改变我们对自然的理解，并修正标准模型，因为理论预测和实验测量之间存在有趣且长期存在的差异。英国实验粒子物理学的研究人员正在努力改进这种测量方法。参与衰变的两种夸克或“味道”在日常生活中是不存在的，但它们在世界上最大的粒子物理实验——欧洲核子研究中心的大型强子对撞机的高能粒子碰撞中大量产生。大型强子对撞机实验继续以前所未有的精度测量这些衰变。我们目前对b->sl+l-衰变的理论描述具有很大且难以量化的不确定性。这妨碍了对目前理论与越来越精确的实验之间的差异作出清晰而明确的解释。它们是SM之外的第一个真正的互动迹象吗？它们是尚未被发现的高能物质成分的印记吗？为了回答这些问题，理论方面必须与实验努力同步改进。我的研究将通过减少理论的不确定性来改善理论方面，从而使发现新的物质类型或衰变中的相互作用可以用现有的数据来证实或反驳。为此，我将使用各种数学和统计工具，并将使用其他类型的底夸克衰变的数据来磨练我的预测的准确性。

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.