A study of angular asymmetries in the rare decay B (right arrow) K*[lambda]⁺[lambda]⁻

This 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.