Ritchie, Jack L., 1955-2012-09-042017-05-112012-09-042017-05-112008-08http://hdl.handle.net/2152/17752textThis dissertation describes studies of the rare quark transition process b → s`+` −, in particular the B meson decay B → K∗ ` +` − where the ` +` − is either e +e − or µ +µ −. These decays are highly suppressed in the Standard Model and could be strongly affected by new physics. The angular observables describing the lepton forward-backward asymmetry and the longitudinal K∗ polarization are measured in this mode. The measurements were performed using the BABAR detector at the SLAC PEPII storage ring running at the Υ(4S) resonance. The analysis was performed on a 349 fb−1 sample corresponding to 384 million BB pairs. The data was collected over a period of six years beginning in 1999. For low dilepton invariant masses, m`` < 2.5 GeV/c2 , we measure a lepton forward backward asymmetry AFB = 0.24+0.18 −0.23 ± 0.05 and a K∗ longitudinal polarization FL = 0.35 ± 0.16 ± 0.04. For m`` > 3.2 GeV/c2 , we measure AFB = 0.76+0.52 −0.32 ± 0.07 and FL = 0.71+0.20 −0.22 ± 0.04.electronicengCopyright is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works.Mesons--DecayParticles (Nuclear physics)