A Search for the Process K⁺ → π⁺ + π⁰ + γ

Citation

Macek, Robert James (1965) A Search for the Process K⁺ → π⁺ + π⁰ + γ. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Q6VQ-ZJ68. https://resolver.caltech.edu/CaltechETD:etd-09302002-103926

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. A search for the process [positive kaon going to positive pion, neutral pion, photon] has been made using counter and spark chamber techniques. The experiment was designed to detect all of the products of the process and measure sufficient quantities to overdetermine the kinematical parameters. Positive pions from [postive kaon] decays at rest were detected in a scintillation counter hodoscope sensitive to pions with energies between 55 and 105 Mev. Positive identification of the [positive pion] was achieved by observing the [pion][...] decay on photographs of the hodoscope counter pulses displayed on a fast oscilloscope. The primary photon and the two [neutral pion] decay photons were observed by the showers produced in spark chambers constructed of several radiation lengths of steel plate. Additional spark chambers determined the [pion] and K trajectories which, combined with a measurement of photon angles, overdetermine the K[...] kinematics by two parameters. A total of 4.3 x 10[superscript 6] stopping K's were counted by the apparatus whose overall efficiency for detecting K[...] events is 2.5 x 10[superscript -3]. One or possibly two events survived all the K[...] selection criteria. Because approximately one or two background events would be expected to survive the same selection criteria; the results must be presented as an upper limit of about 2 x 10[superscript -4] on the K[...] branching ratio for the portion of the [positive pion] spectrum from 55 to 85 Mev. This upper limit is in agreement with the prediction based on the internal bremsstrahlung mechanism and with other experiments which obtain the branching ratio by another approach.

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