CP violation is a well-established phenomenon in particle physics, but until 2001 it was only observed in kaons. In the last decade, several matter-antimatter asymmetries have been observed in neutral B mesons in line with the expectations of the Standard Model of the weak interaction. Direct CP violation is also expected in the decay rates of charged B+ mesons versus that of B- mesons, though the greatest effects are present in a decay that occurs just twice in 10 million decays. Such rarity requires huge samples to study and this is exactly what the LHC, and its dedicated B-physics experiment LHCb provide. This thesis presents an analysis of the first two years of LHCb data. The author describes the first observation of the rare decay, B- → DK-, D → π-K+ and the first observation of direct CP violation in this B decay. The work constitutes essential information on the experiment’s measurement of a fundamental parameter of the theory and stands as a benchmark against which subsequent analyses of this type will be compared.

This book presents the latest results on the branching fraction and phase space distribution of B0 and Bs0 decays into final states including excited neutral charm mesons. This work represents four years of research, and the book describes in detail all the necessary steps and techniques required to perform a physics analysis of the data recorded by the LHCb experiment in the years 2016–2018. Although the results presented in this book represent the first measurement of such decays, the text is written in a manner accessible to Ph.D. students and early career researchers. Thus, all the contents included in this book are described in a pedagogical way, including technical details that would allow the results to be reproduced in future. In addition to the methodology used to perform these measurements, the book also includes a description of the theoretical background required to interpret the results presented, as well as a technical description of the LHCb detector, which provided the data sample used in this study.

Our current understanding of the fundamental building blocks of the Universe, summarised by the Standard Model of particle physics, is incomplete. For example, it fails to explain why we do not see equal, or almost equal, numbers of particles and their antiparticle partners. To explain this asymmetry requires, among other effects, a mechanism known as charge-parity (CP) violation that causes differences between the rates at which particles and antiparticles decay. CP violation is seen in systems containing bottom and strange quarks, but not in those with up, charm or top quarks. This thesis describes searches for particle-antiparticle asymmetries in the decay rates of charmed mesons. No evidence of CP violation is found. With current sensitivities, an asymmetry large enough to observe probably could not be explained by the Standard Model. Instead an explanation could come from new physics, for example contributions from supersymmetric or other undiscovered heavy particles. In the thesis, the development of new techniques to search for these asymmetries is described. They are applied to data from the LHCb experiment at CERN to make precise measurements of asymmetries in the D^+->K^-K^+pi^+ decay channel. This is the most promising charged D decay for CP violation searches.

Dealing with the CP violation, from quarks to leptons, this publication reviews the field, from both the theoretical and experimental point of view, while planning for the experimentation at LHC and considering possible facilities for kaon, B meson and neutrino physics.

This book offers the first strong evidence of the existence of CP violation in neutral B decays extracted from sophisticated B factories in the US and Japan. It also holds out the expectation of rare B decays and D, K physics in the near future. In addition, new physics beyond the Standard Model is described. Both experimental and theoretical points of view are given.