We live in a universe made of matter. However, according to modern theories of cosmology, equal populations of matter and antimatter should have been produced at the beginning of the universe. A very natural and profound question then arises; Where does the asymmetry between matter and antimatter that we are observing now come from?A. Sakharov [1] emphasized that there are three essential elements for building theories that can explain the excess of matter over antimatter in the universe:1. departure from thermal equilibrium;2. reactions that change the baryon number must have occurred in the early universe; and 3. the existence of CP violation. Here, CP violation means that there is a property difference between matter and antimatter. CP violation is therefore one of the essential elements in any attempt to understand the history of our universe. Until 1964, physicists believed that there was no difference between matter and antimatter, even though antimatter has opposite charges and internal quantum numbers. In other words, it was believed that there was symmetry between matter and antimatter, i.e. CP symmetry. Violation of CP symmetry was found (quite unexpectedly) in the decays of neutral K mesons in 1964 [2]. Since then, an enormous theoretical and experimental effort has been made to reveal the origin of this phenomenon. In 1973, Kobayashi and Maskawa (KM) [3] proposed a theory of quark mixing that can introduce CP violation into the scope of the Standard. Model (SM) of elementary particle physics. They demonstrated that the quark flavor mixing matrix with a measurable complex phase introduces CP violation into quark interactions. This requirement is met if there are at least six flavors of this......half of the card......there is such an effect, we should see an opposite systematic effect between the even and odd CP modes, since the their asymmetry should be equal in magnitude but opposite in sign. This is an excellent control of the measurement procedure. For these reasons the B0 → J/ψKL mode is as important as the Golden mode in the sin2φ1 measurement, although it is expected to have more information due to the experimental difficulty in detecting KL. Apart from other charmonium+K0 modes (such as ψ(2S)K0 or χc1K0), the next mode to use in the φ1 measurement is B0 → J/ψK∗0, where K∗0 decays into KS andπ0. Although this decay mode is the CP eigenstate and its decay proceeds with the same quark diagram as the Golden mode, both decay products have spin 1 and the final state is a mixture of even and odd CP states. We need to use the angular information of the decay products to separate the contributions of the different CP components.