Study of ambiguities in πp → ΛK0 scattering amplitudes

  • A. V. Anisovich
  • R. Beck
  • E. Klempt
  • V. A. Nikonov
  • A. V. Sarantsev
  • U. Thoma
  • Y. Wunderlich
Regular Article - Experimental Physics

Abstract

Amplitudes for the reaction π pΛK 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.

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Copyright information

© SIF, Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • A. V. Anisovich
    • 1
    • 2
  • R. Beck
    • 1
  • E. Klempt
    • 1
  • V. A. Nikonov
    • 1
    • 2
  • A. V. Sarantsev
    • 1
    • 2
  • U. Thoma
    • 1
  • Y. Wunderlich
    • 1
  1. 1.Helmholtz-Institut für Strahlen- und KernphysikUniversität BonnBonnGermany
  2. 2.Petersburg Nuclear Physics InstituteGatchinaRussia

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