The polarized target asymmetry AN for π−p→→γn has been measured by coincident detection of the γ and the neutron at several angles across the Δ resonace energy region. A high-resolution NaI γ spectrometer together with good time-of-flight information for the neutron resulted in excellent separation of this radiative capture reaction from the much higher cross-section charge exchange reaction π−p→→π0n. Statistical uncertainties are ΔAN=0.02-0.04, representing a significant improvement over previous results. The new data are discussed in the context of recent theoretical models.
No description provided.
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.
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No description provided.
No description provided.
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The P parameter for π + p scattering at 236.3 MeV has been measured between 50° and 146° c.m. with very low background using a butanol polarized proton target. The resulting D phases are in fair agreement with dispersion relation values.
No description provided.
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Differential cross sections for pi- p and pi+ p elastic scattering were measured at five energies between 19.9 and 43.3 MeV. The use of the CHAOS magnetic spectrometer at TRIUMF, supplemented by a range telescope for muon background suppression, provided simultaneous coverage of a large part of the full angular range, thus allowing very precise relative cross section measurements. The absolute normalisation was determined with a typical accuracy of 5 %. This was verified in a simultaneous measurement of muon proton elastic scattering. The measured cross sections show some deviations from phase shift analysis predictions, in particular at large angles and low energies. From the new data we determine the real part of the isospin forward scattering amplitude.
Elastic PI- P cross section for incident kinetic energy 43.3 MeV for the rotated target data. Errors shown are statistical only.
Elastic PI- P cross section for incident kinetic energy 43.3 MeV. Errors shown are statistical only.
Elastic PI- P cross section for incident kinetic energy 37.1 MeV. Errors shown are statistical only.
High quality analyzing powers for the π−p→→π0n reaction have been obtained with a polarized proton target over a broad angular range at incident kinetic energies of 98.1, 138.8, 165.9, and 214.4 MeV. This experiment nearly doubled the existing πN single-charge-exchange database for energies ranging from 10 to 230 MeV, with 36 new analyzing powers. The Neutral Meson Spectrometer was used to detect the outgoing neutral pions. The data are well described by recent phase-shift analyses. When combined with high-precision and accurate cross section data at the same energies, the data can provide a good test of the degree of isospin breaking in the region of the Δ(1232) resonance. They will also be helpful for constraining the evaluation of the pion-nucleon σ term from the scattering amplitudes.
First error is total uncertainty.
First error is total uncertainty.
First error is total uncertainty.
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.
We have measured the cross section, the angular distribution, and the Λ polarization for the reaction π−p→ΛK0. A spark-chamber spectrometer was used to collect 8400 ΛK0 events at fourteen beam momenta near ΣK threshold. Our data do not show the prominent cross-section enhancement suggested by some previous experiments. However, detailed structure in the cross section and the angular distribution agrees well with a simple model which includes a cusp effect at ΣK threshold.
No description provided.
BACKWARD-FORWARD PRODUCTION ASYMMETRY.
AVERAGE LAMBDA POLARIZATION.
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