I am currently a fourth year PhD student, working on LHCb, with a focus on measuring CP angle gamma.
Until the 1960's, matter and antimatter were understood to behave equivalently, such that if one reaction between matter particles proceeds at a given rate, its 'mirror-image' antimatter counterpart should proceed at the same rate. This is described mathematically by 'CP symmetry'. However, beginning with Cronin and Fitch's Nobel-winning efforts in 1964, a series of experiments revealed the inadequacy of this view; CP symmetry is observably violated - albeit only slightly, and only for a small class of reactions! The dominant theory of fundamental physics - the 'Standard Model' - does allow the possibility of some CP violation, which is parameterized by the constant gamma. Since the amount of CP violation is small, very large quantities of data must be analysed in order to measure gamma with any degree of precision. This task is also crucial for comparing the Standard Model with potential alternatives, since the degree of allowed CP violation often differs between them. CP violation has especially important implications for the origin of the known Universe - could it explain why we live in a matter-dominated world?