CP Violation and the Dominance of Matter

1 Department of Physics University of Arizona The observable Universe reveals a clear dominance of matter over antimatter. If this asymmetry is consistent with the Universe as a whole, then a contradiction arises between observation and any naïve formulation of Big Bang theory. CP violation, violation of the combined C (charge conjugation) and P (parity) operators, is one of three necessary conditions of matter dominance theorized by Sakharov in 1967. Therefore, further study of CP violation is warranted to determine its role in the evolution of a matter-dominated Universe. There are two ways by which violation might occur: direct and indirect. The first possibility is that physical eigenstates may be written as a linear combination of CP eigenstates – a small amount of the opposite CP eigenstate might cause CP violation. This violation from mixing of CP eigenstates is also called indirect CP violation. Independent of indirect violation, CP violation might also occur in the decay or direct CP violation. A famous experiment, which investigated the possibility of indirect CP violation, was conducted in 1964. Since then several experiments have been conducted to determine if CP violation also exists in the decay. This review summarizes the methodology of two such experiments. Despite the progress made in understanding the nature of CP violation, the future of research of CP violation remains promising. Several proposed experiments involve determining the degree of CP violation in much more rare decays. We summarize one such future experiment of analyzing CP violation in these decays. Finally, due to the rare occurrence of CP violation, future investigations will require high rate experiments with high efficiency detectors. To this end we test the efficiency of one such detector which may be used in such experiments. A high rate environment similar to that expected in proposed CP violating experiments was used to examine the detector’s behavior. In particular, this detector was tested using electrons from KL decays