General Public Summary

High-Energy Physics	The goal of the high-energy physics is the study of the fundamental constituents of matter and their interactions. The study of the most fundamental laws allows the comprehension of more complex phenomena in other fields of physics and other sciences. This opens the road for many practical applications no one could think of now.
Four Forces	All laws of physics arise from four fundamental forces which are Gravitation, the Electromagnetic force and the nuclear Strong and Weak forces. Only the two first have effects on a macroscopic scale, but all contribute to the balance of matter and life. High-energy physics allows to observe these forces separately. Physicists study them by producing high energy collisions of fundamental particles, for instance protons at the future LHC accelerator at CERN.
The Standard Model	The results of these experiments are compared with a theory of the fundamental interactions called ``Standard Model''. It describes all known particles and all forces except for Gravitation. The theory is thus incomplete. One of the goals of the LHC is to find hints how to complete it, leading to a broader theory which would predict different results than the Standard Model at very high energies. The aim of LHC is to reveal these - probably subtle - differences
The LHCb experiment	The LHCb experiment, presently in preparation at LHC, concentrates its study on the differences between matter and antimatter. The latter is a kind of negative of matter having (almost) the same properties, but all the opposite electric charges. To do this, LHCb studies a particle called B meson. The decays of this particle are due to the weak force and are very sensitive to the light difference between the matter and the antimatter. This difference, called CP asymmetry (or CP violation), is one of the least understood and experimentally constrained physical phenomena to date. It is the reason the universe is made of matter and not anti-matter (or nothing at all...)
The VeLo	Within the framework of this thesis, we collaborated to the development of silicon detector, which will be part of the LHCb experiment.
Rare B Decays	We also studied the sensitivity of the LHCb experiment to very rare decays of the B meson. Those are likely to be sensitive to physics beyond the Standard Model. In this case, this study will make it possible to reveal and characterize the limitations of the theory. In the contrary case, it will make it possible to measure badly known parameters and thus to refine the Standard Model. We have developed a simulation and a strategy of selection of these events. We show that the sensitivity of the LHCb experiment will be higher than that of other current or future experiments.

More information about the experiments, accelerators and laboratories cited in this page can be found on the links page.
My thesis's first chapter is a more detailed general public overview.