UBC Theses and Dissertations
Exclusive measurements of [pi]N --> [pi][pi]N Kermani, Mohammad Arjomand
The pion induced pion production reactions —> 7 r ±7r+ n were studied at projectile incident energies of 223, 243, 264, 284, and 305 MeV. The Canadian High Acceptance Orbit Spectrometer (CHAOS) was used to detected the charged particles, which originated from the interaction of the incident pion beam with a cryogenic liquid hydrogen target. The experimental results are presented in the form of single, double and triple differential cross sections. Total cross sections obtained by integrating the differential quantities are also reported. The experimental data, namely the ir~p —> 7r~7r+n double differential cross sections, were used as input to the Chew-Low extrapolation procedure which was utilized to determine on-shell 7r+7r_ elastic scattering cross sections in the near threshold region. The Chew-Low results (the extrapolated irir cross sections) were then used in a dispersion analysis (Roy equations) to obtain the -KIT isospin zero S-wave scattering length. We find a° = 0.209 ± 0.011/x-1. In addition, the invariant mass distributions from the 7r~) channel were fitted to determine the model parameters for the extended model of Oset and Vicente-Vacas. We find that the model parameters obtained from fitting the (7r+7r_ ) data do not describe the invariant mass distributions in the (7r+7r+) channel.
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