Upper limits on resonance contributions to proton-proton elastic scattering in the c.m. mass range 2.05-2.85 GeV/c(2)

摘要

Recently published excitation functions in proton-proton (pp) elastic scattering observables in the laboratory energy range 0.5-2.5 GeV provide an excellent data base to establish firm upper limits on the elasticities eta(el) = Gamma(el)/Gamma(tot) of possible isovector resonant contributions to the nucleon-nucleon (NN) system. Such contributions have been predicted to arise from dibaryonic states, with c.m. masses between 2.1-2.9 GeV/c(2), but have not been confirmed experimentally. A method to determine quantitatively the maximum value of reel compatible with experimental data is presented. We use energy-dependent phase shift fits to the pp data base to model the non-resonant interaction. Based upon the differential cross-section data measured by the EDDA Collaboration an unbiased statistical test is constructed to obtain upper limits on eta(el), that exclude larger values with a 99% confidence level. Results in the c.m. mass range 2.05-2.85 GeV/c(2) and total widths of 10-100 MeV/c(2) in the partial waves S-1(0), D-1(2), P-3(0), P-3(1), and F-3(3) are presented and discussed.