The Physics of the B Factories

Abstract

In their classic paper, Kobayashi and Maskawa (1973, “KM”) pointed out that CP violation could be naturally incorporated into the Standard Model (SM) as an irreducible complex phase in the weak interaction quarkflavor- mixing matrix if the number of quark flavors was six. This was remarkable because at that time only the three quarks of the original Gell-Mann (1964) and Zweig (1964a) quark model — i.e., the u-, d- and s-quarks — were experimentally established. The situation changed dramatically in late 1974 with the discovery of the cquark at Brookhaven (Aubert et al., 1974) and SLAC (Augustin et al., 1974) and the 1977 discovery of the bquark at Fermilab (Herb et al., 1977). By 1980, the KM idea, by then embodied in the Cabibbo-Kobayashi-Maskawa (CKM) quark flavor mixing matrix (Cabibbo,1963; Kobayashi and Maskawa, 1973), was accepted as an integral component of the Standard Model, even though its raison d’etre, the CP-violating complex phase, had not been measured (Kelly et al., 1980).