Ke Li

The mixing between Bs0 - Bs0 bar and Bd0 - Bd0 bar leads to the two eigenstates of definite masses (heavy, m H and light, m L) and widths (GammaH and GammaL). The mass differences in the two systems have an important impact on our knowledge of the unitary triangle and the Standard Model. The mass difference Delta md has been well measured. However no direct measurements of Delta m s have been made because of the high oscillation frequency in B0s system. A large mass difference suggests a large and measurable width difference (Delta m s ≡ Gamma L - Gamma H, which can be used (and may be the only achievable way currently) to determine Delta m s.

The B0s to J/psi phi and B0d to J/psi Kstar0 are pseudo-sealer to vector-vector decays governed by three decay amplitudes, representing the coupling of the B meson to states polarized longitudinally A0, and parallel A parallel or perpendicularly A perp in the transverse plane. In the B0s system, the mass eigenstates are nearly CP eigenstates and so are the final observed polarized states. A combined analysis based on lifetime and angular information allows for a separation of the heavy (CP odd) and light (CP even) eigenstates and a measurement of the width difference. The channel B0d to J/psi Kstar0 is related to B0s to J/psi phi by SU(3) flavor symmetry, and provides a powerful validation of the analysis technique.

In this dissertation, I present a time-dependent analysis of these decays based on the dimuon data collected by the CDF Collaboration at Fermi National Accelerator Laboratory from February 2002 to February 2004 during the Run II of the Tevatron, corresponding to a total luminosity of approximately 260 inv pb. From these data, I measure the transverse amplitudes of the two decays, the lifetimes of the B0s (heavy and light) and the B0d and the width difference in the B0s system.

For B0s, we obtain: [special characters omitted]

For B0d, we obtain: [special characters omitted]

We conduct the first direct measurements of Delta Gamma s and the lifetimes of the two mass components in the B0s system. The results of the decay amplitudes of the B0s are the most precise measurements currently, and those of the B0d are competitive compared with B factories.