A Precision Measurement of pp Elastic Scattering Cross Sections at Intermediate Energies

We have measured differential cross sections for \pp elastic scattering with internal fiber targets in the recirculating beam of the proton synchrotron COSY. Measurements were made continuously during acceleration for projectile kinetic energies between 0.23 and 2.59 GeV in the angular range $30 \leq \theta_{c.m.} \leq 90$ deg. Details of the apparatus and the data analysis are given and the resulting excitation functions and angular distributions presented. The precision of each data point is typically better than 4%, and a relative normalization uncertainty of only 2.5% within an excitation function has been reached. The impact on phase shift analysis as well as upper bounds on possible resonant contributions in lower partial waves are discussed.Comment: 23 pages 29 figure

Upper limits on resonance contributions to proton-proton elastic scattering in the c.m. mass range 2.05-2.85 geV/c2

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