B mesons can decay to many different combinations of lighter particles, and the first thing one must do is to decide which ones are most promising for CP violation studies.  In one type of study, we look at final combinations that are what we call CP eigenstates.  For such a state, if we turn every decay product into its antiparticle, you get the same collection of particles.  For example, the final combination K⁺K^-, where K⁺ is a meson containing a u-quark and a s-antiquark (s-bar), and the K^- contains u-bar and s, can be a CP eigenstate.  Note that the total combination includes u and u-bar, plus s and s-bar: two quark-antiquark pairs.  Such combinations can occur only if the parent meson is electrically neutral.  If CP is not violated, then the B⁰ and B⁰-bar should decay in an identical manner to CP eigenstates.  Differences in the decay rates would be evidence of CP violation.

However, some of these differences can be pretty subtle.  The most promising studies involve rate differences that may be small and are expected to depend on when the B⁰ or B⁰-bar decays.  The decay is so fast, though, that no timing device exists that could measure it; the average B⁰ decays in one-trillionth of a second.  The way in which time at this scale is measured in particle decay is to make it move fast, and then measure the distance between its birth and its decay.  In addition, since it's impossible to tell from the decay whether it came from B0 or B0-bar, we must detect the particles produced in conjunction with the B. To accomplish all this, we need state-of-the art particle accelerators and detectors.  This is the aim of the B-factory experiments.