David Edward Smith
Published: 2006
Total Pages: 141
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This thesis describes a search for the rare decay K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{gamma} using data from the KTeV experiment, using the topology K{sub L} {yields} {pi}{sup 0}{pi}{sub D}{sup 0}{gamma} (where {pi}{sub D}{sup 0} {yields} {gamma}e{sup +}e{sup -}). Due to Bose statistics and the real nature of the photon, the K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{gamma} decay can proceed at lowest order only by the Cp conserving direct emission of an E2 photon. The decay vanishes to O(p{sup 4}) in chiral perturbation theory and is a probe of the theory to the sixth order. The primary background to this decay consists of K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{pi}{sub D}{sup 0} events with one lost photon. The upper limit for the decay K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{gamma} presented in this thesis is 2.32 x 10{sup -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 K{sub L} {yields} {pi}{sup 0}{pi}{sup 0}{pi}{sub D}{sup 0} background of 0.37 {+-} 0.28 events. The previous upper limit for this decay was 5.6 x 10{sup -6} at the 90% confidence level.
