Nucleon-nucleon elastic scattering analysis to 2.5 GeV

A partial-wave analysis of NN elastic scattering data has been completed. This analysis covers an expanded energy range, from threshold to a laboratory kinetic energy of 2.5 GeV, in order to include recent elastic pp scattering data from the EDDA collaboration. The results of both single-energy and energy-dependent analyses are described.Comment: 23 pages of text. Postscript files for the figures are available from ftp://clsaid.phys.vt.edu/pub/said/n

A multi-processor CAMAC-based on-line system

The data acquisition system for the PS199 experiment is described. It is based on CAMAC modules with three J11 Starburst processors used for parallel event reduction and event building. A MicroVAX II and two VAXstations perform the run control and monitoring. A PC takes care of the laser calibration

A high-statistics measurement of the p̄p → n̄n charge-exchange reaction at 875 MeV/c

A new measurement of the differential cross section and of the analysing power A0n of the charge-exchange reaction p̄p → n̄n at 875 MeV/c is presented. The A0n data cover the entire angular range and constitute a considerable improvement over previously published data, both in the forward and in the backward hemisphere. The cross-section data cover only the backward region, but are unique at this energy. A careful study of the long-term drifts of the apparatus has allowed to fully exploit the good statistics of the data

A new measurement of the pbar p -> nbar n charge-exchange differential cross-section at LEAR

We have measured the View the pbar p \u2192 nbar n charge-exchange differential cross-section at two incoming momenta (601.5 and 1202 MeV/c) at the CERN Low Energy Antiproton Ring. After reviewing the experimental method, the data analysis is fully detailed, and the results on the whole statistics available in the centre of mass forward hemisphere are given. A precision in the absolute normalisation of 2% and 4% at 601.5 and 1202 MeV/c respectively is achieved, while over most of the angular range the point-to-point error is lower than 1%. The forward peak associated with the nearby pion pole and a dip-bump structure are accurately measured. The \u201cChew\u201d extrapolation to the pion-pole suggests a \u201clow\u201d value for the \u3c0NN coupling constant gc2

Differential cross sections and analysing powers for PP -> π^-π⁺ and K⁻K⁺ from 360 to 1550 MeV/c

Abstract Analysing powers and differential cross sections for p p → π − π + and p p → K − K + have been measured over the full angular range using a polarised target at LEAR at 20 beam momenta from 360 to 1550 MeV/c. Discrepancies in the normalisation of earlier d σ/ d Ω data at low momenta are clarified. Above 1000 MeV/c, A0N results confirm values close to +1 over most of the angular range for both reactions, in excellent agreement with earlier data of lower statistics. Below 1000 MeV/c, where the analysing power is measured for the first time, large variations of A0N with energy and angle are present

New measurement of the anti-pp→anti-nn differential cross-section from PS206

Experiment PS206 has measured with high precision the differential p̄p → n̄n cross-section at the CERN Low Energy Antiproton Ring. First results have already been published for the forward region, based on part of the collected statistics. Now the whole 601 MeV/c sample has been analysed and the new results are presented both for the forward hemisphere and for the backward region. The crucial tasks of the efficiency measurement and the studies of the systematic effects, that limit the precision of the measurement, are also discusse