1 research outputs found
One-loop analysis of the reaction pi N to pi pi N
Single pion production off nucleons is studied in the framework of heavy
baryon chiral perturbation theory to third order in the chiral expansion. Using
total and some older differential cross section data to pin down the low-energy
constants, most of the recent differential cross sections and angular
correlation functions can be described as well as total cross sections at
higher energies. We show that the contributions from the one loop graphs are
essentially negligible and that the dominant terms at second and third order
are related to pion-nucleon scattering graphs with one pion added. We also
discuss the possibility of extracting the pion-pion S-wave scattering lengths
from the unpolarized data.Comment: 57 pp, LaTeX file, 13 figures (uses epsf