The differential cross section and recoil-proton polarization in π−−p elastic scattering at 310-MeV incident-pion energy has been measured. The differential cross section was measured at 28 angles in the angular region 25<~θlab<~160 deg. The fractional rms errors were typically 3%. The reaction was observed by counting the scattered pions emerging from a liquid-hydrogen target with a counter telescope consisting of scintillation and Čerenkov counters. Simultaneously, the recoil-proton polarization was measured at four angles in the angular region 114<θc.m.<146 deg. The recoil protons from the liquid-hydrogen target were scattered from a carbon target and the left-right asymmetry was measured. Scintillation counters were used throughout to detect the particles.
No description provided.
No description provided.
The asymmetry parameter A in π−p elastic scattering at incident pion laboratory kinetic energies Tπ of 98, 238, and 2922 MeV and in π−p charge-exchange scattering π−p→π0n at Tπ=238, 292, and 310 MeV have been measured over a wide range of scattering angles (typically from about 60° to 130° c.m.) with a polarized proton target. The data have been used in an energy-independent phase-shift analysis to improve the precision of the pion-nucleon phase shifts, to set new limits on violation of isospin conservation in the pion-nucleon S wave, and to confirm significant charge dependence in the P32 wave.
Axis error includes +- 0.0/0.0 contribution (?////BACKGROUND SUBTRACTION SMALL).
Axis error includes +- 0.0/0.0 contribution (?////BACKGROUND SUBTRACTION SMALL).
Axis error includes +- 0.0/0.0 contribution (?////BACKGROUND SUBTRACTION SMALL).
Analyzing powers of pion-proton elastic scattering have been measured at PSI with the Low Energy Pion Spectrometer LEPS as well as a novel polarized scintillator target. Angular distributions between 40 and 120 deg (c.m.) were taken at 45.2, 51.2, 57.2, 68.5, 77.2, and 87.2 MeV incoming pion kinetic energy for pi+ p scattering, and at 67.3 and 87.2 MeV for pi- p scattering. These new measurements constitute a substantial extension of the polarization data base at low energies. Predictions from phase shift analyses are compared with the experimental results, and deviations are observed at low energies.
Analyzing power for PI+ P elastic scattering at incidient kinetic energy 87.2 MeV from the data set 1.
Analyzing power for PI+ P elastic scattering at incidient kinetic energy 68.4 MeV from the data set 1.
Analyzing power for PI+ P elastic scattering at incidient kinetic energy 57.2 MeV from the data set 1.
The polarization parameter has been measured for π − p elastic scattering in the backward region at 3.5 GeV/ c incident momentum. The experimental set-up consisted of a polarized target in a spectrometer magnet, hodoscopes and wire spark chambers. Data are presented for the range −0.95< u ⩽−0.19 GeV 2 . An isospin analysis has been carried out to separate the I u = 1 2 and I u = 3 2 contributions.
BACKWARD SCATTERING.
Analyzing powers for π−p elastic scattering have been measured at TRIUMF using the CHAOS spectrometer and a spin-polarized target. These data were collected at a bombarding energy of Tπ=279MeV and cover an angular range of 53<~θc.m.π<~180°. There is good agreement between these data and the latest partial wave analysis from the VPI/GWU group.
Analysing power measurement.
Analyzing powers for πp elastic scattering at bombarding energies below the Δ(1232) resonance were measured at TRIUMF using the CHAOS spectrometer and a polarized spin target. This work presents π− data at six incident energies of 57, 67, 87, 98, 117, and 139 MeV, and a single π+ data set at 139 MeV. The higher energy measurements cover an angular range of 72°<~θc.m.<~180° while the lower energies were limited to 101°<~θc.m.<~180°. There is a high degree of consistency between this work and the predictions of the VPI/GWU group’s SM95 partial wave analysis.
Analysing power measurements for a 139 GeV PI+ beam (standard track).
Analysing power measurements for a 139 GeV PI- beam (standard track).
Analysing power measurements for a 117 GeV PI- beam (standard track).
Angular distributions of the analyzing powers for π+p→ and π−p→ elastic scattering have been measured in a single-scattering experiment employing a polarized proton target. Measurements were obtained for pion energies of 98, 139, 166, 215, and 263 MeV. The addition of these data to the existing πp database significantly reduces the uncertainties in all S and P phase shifts for πp reactions over the delta resonance.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 98 MeV.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 139 MeV.
Measured values of the analyzing power for PI+ P elastic scattering at incident kinetic energy 166 MeV.
We have measured the polarization in π − backward elastic scattering at 2.22, 2.46, 2.71 and 3.50 GeV/ c incident momenta, in the u -range−1.0 ≦ u ≦0.1 (GeV/ c ) 2 . The experiment used a polarized proton target and detected both pions and protons. We have found large discrepancies between the new data and the result of even the latest phase-shift analysis.
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No description provided.
No description provided.
Analyzing powers for πp elastic scattering were measured using the CHAOS spectrometer at energies spanning the Δ(1232) resonance. This work presents π+ data at the pion kinetic energies 117, 130, 139, 155, 169, 180, 193, 218, 241, and 267 MeV and π− data at 87, 117, 193, and 241 MeV, covering an angular range of 50°<~θc.m.<~180° at the higher energies and 90°<~θc.m.<~180° at the lower energies. Unique features of the spectrometer acceptance were employed to reduce systematic errors. Single-energy phase shift analyses indicate the resulting S11 and S31 phases favor the results of the SM95 phase shift analysis over that of the older KH80 analysis.
Measurement of the PI+ analysing power at 117 MeV.. The data were collected in the conventional mode and may be independently floated within the systematic error.
Measurement of the PI+ analysing power at 139 MeV.. The data were collected in the conventional mode and may be independently floated within the systematic error.
Measurement of the PI- analysing power at 87 MeV.. The data were collected in the conventional mode and may be independently floated within the systematic error.