There has already been detected an asymmetry between particles and antiparticles in the K meson system, by Val Fitch and Jim Cronin in 1980. The symmetry that exchanges a particle and antiparticle is called charge conjugation, C, because the charges change sign under this. Coupled with parity inversion P of x to -x, CP can be formed. It is the combined CP that is violated in the Kaon system. The neutral K0, composed of a strange and an antidown quark, is converted to its antiparticle, anti-K0 by CP. Second order weak interactions or virtual W boson exchanges do this in the physical world, and the resulting mass eigenstates become a mixture of these. The same processes should occur in the standard model with another "down" type quark of charge -1/3, the bottom or b quark. The B0 meson (b quark and antidown d quark) should convert to its antiparticle anti-B0, by similar processes. Because these are more massive than kaons, there are fewer strong interacting states to couple to the B's, and the measurements in the B system are almost an exact test of the quark mixing theory in the weak interactions, as opposed to the kaon system which is very complicated by strong interactions.
CP violation in the B system will be tested in "B Factories" that will produce 30 million B mesons a year. They are being built at the Stanford Linear Accelerator Center (SLAC) and at KEK in Tsukuba, Japan, and will turn on in 1999. UCI has a group composed of Andy Lankford, Mark Mandelkern, Jonas Schultz, Dave Stoker, Keith Gollwitzer, and George Zioulas working on the SLAC detector which is called BaBar (the Bar standing for the anti-B, and B and anti-B are formed in pairs).
Relativistic Quantum Field theory couples CP violation with the time reversal transformation T (t -> -t) to make a conserved combination of CPT. So a CP violation is equivalent to a T violation. In the standard model, this occurs by mixing the three down quark states defined by their weak interactions with corresponding up quarks (or weak eigenstates) to form the actual down quark mass eigenstates of d, s, and b quarks that appear in meson and baryon spectroscopy. In the 3 by 3 mixing matrix one arbitrary phase ei delta is allowed. A phase in the quantum Hamiltonian automatically violates a hermitian Hamiltonian and is equivalent to T violation.
In the B mixing to an anti-B, the anti-b and d quarks in the B0 annihilate by exchanging an up quark (charge +2/3) of u, c (charm), or t (top) to form two virtual W bosons of weak interactions, and then reform to b and anti-d quarks forming an anti-B0. The complex numbers for the product of mixing matrix elements for the u, c, and t exchanges form a closed triangle. One angle is the CP violating phase delta, and the others are called alpha and beta. B decays involving b -> c quark transitions have CP violating oscillations proportional to sin(2 beta), while those involving b -> u, have oscillations proportional to sin(2 alpha). Only if delta is non-zero will alpha and beta differ from 0 or 180 degrees to allow an oscillation.
My research has taken two related methods of analyzing CP violation in the B system. First, I use about 10 experiments that constrain the standard model mixing matrix, and predict the statistically weighted outcomes of the CP violating experiments at the B factories in the standard model. This will help determine when that model is violated.
To further evaluate the capabilities of these experiments for detecting new physical models, I analyze the constraints and B factory experiments with an extended model that has an extra down quark in each of the three quark generations, but no new up type quarks like u, c, and t. Such a model and its new quarks may be motivated by supersymmetric string theory. These models mix more quarks and introduce more phases, and lead to first order weak interaction mixing of B0 and anti-B0 mesons, as first quantitatively evaluated by Myron Bander, Michael Shin, and myself. The weakness of present constraints on this model allow almost any values of delta, alpha, and beta to be obtained in the B factory experiments, in contrast to the fairly constrained results predicted by the standard model. Thus the B factories might see quite different results from the standard model results, and the differences might show up early in gathering data. This research has involved collaboration with an advanced undergraduate, Woon-Seng Choong, who is now a graduate student at Berkeley, and with Yossi Nir, who is at the Weizmann Institute.