Direct reconstruction of pp elastic scattering amplitudes from experimental data between 0.83 and 2.7 GeV

Abstract

The direct reconstruction of the elastic scattering amplitudes at eleven energies between 0.83 and 2.7 GeV is described. Complete sets of spin dependent observables used for this reconstruction were measured in the nucleon-nucleon experimental program at Saturne II. The invariant amplitudes a, b, c, d and e were deduced using the least square method fit to the experimental data. A search for solutions starting from random initial values was performed to determine different possible sets of amplitudes. The absolute values show a similar angular dependence at all energies and for all solutions. The dependence of phases show discrete ambiguities especially at the higher energies. One of the solutions at 2.1 GeV suggests a behaviour which could be related to a dibaryon resonance of mass 2.73 GeV with the half-width at the half-maximum less than 50 MeV.