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Cross sections based on total PI+ P cross section =25.8 mb (Vondardel, PRL 8, 173 (1962)).
The total cross section for the π−p→π−π+n reaction has been measured at incident pion kinetic energies of 200, 190, 184, and 180 MeV. In addition, the π+p→π+π+n reaction was measured at 200 and 184 MeV. A fit of the cross sections by heavy baryon chiral perturbation theory yields values of 8.5±0.6(mπ−3) and 2.5±0.1(mπ−3) for the reaction matrix elements A10 and A32, which correspond to values for the s-wave isospin-0 and isospin-2 π−π scattering lengths of a0=0.23±0.08(mπ−1) and a2=−0.031±0.008(mπ−1), respectively.
No description provided.
The pion induced pion production reactions π±p→π+π±n were studied at projectile incident energies of 223, 243, 264, 284, and 305 MeV, using a cryogenic liquid hydrogen target. The Canadian High Acceptance Orbit Spectrometer was used to detect the two outgoing pions in coincidence. The experimental results are presented in the form of single differential cross sections. Total cross sections obtained by integrating the differential quantities are also reported. In addition, the invariant mass distributions from the (π+π−) channel were fitted to determine the parameters for an extended model based on that of Oset and Vicente-Vacas. We find the model parameters obtained from fitting the (π+π−) data do not describe the invariant mass distributions in the (π+π+) channel.
Total cross sections were obtained by integrating the differential cross section over all three variables: M(pi,pi)**2, t, Cos(Theta(pi)).
Total cross sections were obtained by integrating the differential cross section over all three variables: M(pi,pi)**2, t, Cos(Theta(pi)).
The reaction π+p→π+π+n was studied in the vicinity of the reaction threshold at ten incident pion beam momenta from 297 MeV/c to 480 MeV/c. From data angular distributions, invariant mass spectra and integrated cross-sections were deduced. The chiral symmetry breaking parameter as determined by this reaction equals to ξ=1.56±0.26±0.39, where the first error is experimental, while the latter reflects the uncertainty in the ansatz used in the extrapolation to the reaction threshold. A comparison with the other reaction channels of the reaction πp→ππN indicates that a single parameter (ξ) is not sufficient to describe low energy ππ interactions.
No description provided.
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