UBC Theses and Dissertations
A measurement of the analysing power of the pn --> pp(¹⁰)⁻ reaction Ponting, Chris
A measurement of the analysing power of the pn → pp(¹S₀)π⁻ reaction, at an incident proton energy of 400 MeV, has been conducted at TRIUMF for pion centre-of-mass angles 56° < θ[sup * sub π]< 86°. The detection of pions, using a pion magnetic spectrometer, and the detection of the two protons, using arrays of Nal bars and thin plastic scintillators, are discussed with respect to the maximisation of an event yield where the two protons are in a relative ¹S₀ angular momentum state. The off-line event definition and the tests employed in the examination of the event set for background and accidental events are also presented in conjunction with the methods employed in the reduction of P-wave contamination. The predictions of a Monte Carlo simulation of this reaction for both S- and P-wave events are compared to the experimental quantities to discover the ratio of the yields for the two partial-waves. A partial-wave analysis has determined the reaction amplitude set for this reaction to a two-fold ambiguity, the results of this experiment show that the analysing power varies dramatically from approximately -0.85 at θ[sup * sub π]≈ 63° to +0.64 at θ[sup* sub π]≈ 83°. This variation is dissimilar to the form of the analysing power for one solution set and is similar to that for the other.
Item Citations and Data