Study of ambiguities in π−p → ΛK0 scattering amplitudes
- 63 Downloads
Amplitudes for the reaction π − p → ΛK 0 are reconstructed from data on the differential cross section dσ/dΩ, the recoil polarization P, and on the spin rotation parameter β. At low energies, no data on β exist, resulting in ambiguities. An approximation using S and P waves leads only to a fair description of the data on dσ/dΩ and P; in this case, there are two sets of amplitudes. Including D waves, the data on dσ/dΩ and P are well reproduced by the fit but, now, there is a multitude of distinct solutions which describe the data with identical precision. In the range where the spin rotation parameter β was measured, a full and unambiguous reconstruction of the partial wave amplitudes is possible. The energy-independent (single-energy) amplitudes are compared to the energy-dependent amplitudes which resulted from a coupled-channel fit (BnGa2011-02) to a large data set including both pion- and photo-induced reactions. Significant deviations are observed. Consistency between energy-dependent and energy-independent solutions is obtained by choosing the energy-independent solution which is the closest to the energy-dependent solution. In a second step, the known energy-dependent solution for low (or high) partial waves is imposed and only the high (or low) partial waves are fitted leading to smaller uncertainties.
- 2.G. Höhler, F. Kaiser, R. Koch, E. Pietarinen, Handbook Of Pion Nucleon Scattering (Fachinform. Zentr. Karlsruhe 1979) p. 440.Google Scholar
- 3.G. Höhler, πN Newslett. 9, 108 (1993).Google Scholar
- 4.R.E. Cutkosky, Pion - Nucleon Partial Wave Analysis, in Proceedings of the 4th International Conference on Baryon Resonances, Toronto, Canada, Jul 14-16, 1980 (Baryon, 1980) QCD161:C45:1980.Google Scholar
- 14.R.D. Baker, Barrelet Zeros in Partial Wave Analysis, RL-76-013.Google Scholar