(1996 - 1999)
I have studied rare radiative B decays to obtain information about the Cabibbo-Kobayashi-Maskawa matrix elements Vtd and Vts. The studies of these quark loop induced processes (electroweak penguin decays) resulted in an improved measurement of the B -> K*g branching fraction, the first observation of the decay B -> K*2(1430)g, improved upper limits on the branching fractions of the decays B -> rg and B -> wg and in an upper limit on the ratio |Vtd/Vts|. In addition, I searched for physics beyond the Standard Model by studying the rate asymmetry of B versus B decaying to K*g. The results of these studies have been published in "Study of Exclusive Radiative B Meson Decays", T.E. Coan et al., Phys.Rev.Lett. 84, 5283 (2000).
I performed the first analysis using the new CLEO silicon vertex detector SVX namely the "Measurement of Charm Meson Lifetimes'' (G. Bonvicini et al., Phys.Rev.Lett. 82, 4586 (1999)) and explored the resolution and systematic uncertainties of the improved charged particle trajectory reconstruction. The understanding of the systematic uncertainties of vertex reconstruction in the multiple-scattering dominated energy region of the Upsilon(4S) played a key role in the analysis. With demonstrated systematic uncertainties of only one micron in decay lengths, the measured charm meson lifetimes have precision comparable to the measurements from dedicated fixed target experiments.