Download or read book Search For the Rare Decay KL {u2192} ?0?0?. written by and published by . This book was released on 2006 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes a search for the rare decay KL → ?0?0? using data from the KTeV experiment, using the topology KL → ?0?$0top{D}$? (where ?$0top{D}$ → ?e+e-). Due to Bose statistics and the real nature of the photon, the KL → ?0?0? decay can proceed at lowest order only by the Cp conserving direct emission of an E2 photon. The decay vanishes to O(p4) in chiral perturbation theory and is a probe of the theory to the sixth order. The primary background to this decay consists of KL → ?0?$0top{D}$ events with one lost photon. The upper limit for the decay KL ?0?0? presented in this thesis is 2.32 x 10-7 at the 90% confidence level. This upper limit was derived from both 1997 and 1999 data, using a blind analysis. The upper limit was derived from a Feldman-Cousins method, based on a weighted total of 0.53 data events in the signal region with an expected KL → ?0?0?$0top{D}$ background of 0.37 ± 0.28 events. The previous upper limit for this decay was 5.6 x 10-6 at the 90% confidence level.