Abstract:

We have carried out a partial-wave analysis of ππ scattering in the mass range 1.0 to 2.08 GeV/c2. We find solutions similar to those obtained in previous analyses below 1.8 GeV/c2 but, in addition, we obtain a new solution which does not suffer from violations of unitarity and is compatible with data from other channels. This solution, when continued to 2.08 GeV/c2, shows a g meson with mass and width of 1.734± 0.010 GeV/c2and 0.322±0.035 GeV/c2 respectively, and an h meson with mass 1.935±0.013 GeV/c2and width 0.263±0.057 GeV/c2. The L = 2 partial wave contains the f meson and an additional resonance with parameters m = 1.502±0.025 Gev/c2, Γ = 0.165±0.042 GeV/c2and x = 0.19±0.03. If we associate this state with the f′(1514), our ππ branching fraction is considerably higher than previous determinations. An SU(3) fit to the 2+ nonet yields a mixing angle of 38.4± 1.3°. © 1979.

Abstract:

We describe the calibration of a large 60 element neutron counter with a threshold of 2.7 MeV equivalent electron energy. The performance of the counter has been measured in the neutron kinetic energy range 8.5-430 MeV using a neutron beam at the CERN Synchrocyclotron. The results obtained for the efficiency as a function of energy are in reasonable agreement with a Monte Carlo calculation. © 1978.

Abstract:

Data on the reaction π-p → π+π-π0 have been taken at 12 and 15 GeV/c with the CERN Omega multiparticle spectrometer. In a 3-pion partial-wave analysis strong production of A20 (1310) and ω* (1675) is observed. Total and differential cross sections are determined and density matrix elements presented as a function of t in the t- and s-channel frames. The energy dependence of A20 production is studied, and a comparison of ω(780), A20(1310) and ω* (1675) production is made. © 1978.

Abstract:

An experiment has been performed on the Omega spectrometer to study the channel π-p → π+π-n at 12 and 15 GeV/. The π+π- angular distribution has been studied in the π+π- invariant-mass region 0.8-2.2 GeV/c2, for events with four-momentum transfer squared from proton to neutron in the range -0.02 to -0.15 (GeV/c)2. The spherical harmonic moments of the angular distribution are presented. Up to a mass of 1.7 GeV/c2 the moments agree with previous experiments. At higher masses Y70, Y80 and Y90 are non-zero and indicate the presence of ππ amplitudes with spin greater than 3. © 1978.