Exclusive measurements of pion nucleon going to pion pion nucleon
[Thesis]
M. A. Kermani
G. Smith
The University of British Columbia (Canada)
1997
202
Ph.D.
The University of British Columbia (Canada)
1997
The pion induced pion production reactions usd\pi\sp{\pm}p\to\pi\sp{\pm}\pi\sp{+}nusd 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 usd\pi\sp{-}p\to\pi\sp{-}\pi\sp{+}nusd double differential cross sections, were used as input to the Chew-Low extrapolation procedure which was utilized to determine on-shell usd\pi\sp{+}\pi\sp{-}usd elastic scattering cross sections in the near threshold region. The Chew-Low results (the extrapolated usd\pi\piusd cross sections) were then used in a dispersion analysis (Roy equations) to obtain the usd\pi\piusd isospin zero S-wave scattering length. We find usda\sbsp{0}{0}=0.209\pm 0.011\mu\sp{-1}.usd In addition, the invariant mass distributions from the usd(\pi\sp{+}\pi\sp{-})usd 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 usd(\pi\sp{+}\pi\sp{-})usd data do not describe the invariant mass distributions in the usd(\pi\sp{+}\pi\sp{+})usd channel.