A nonzero difference of the analyzing powers due to charge symmetry breaking has been measured with high precision in np elastic scattering at a neutron beam energy of 347 MeV. The neutron beam and proton target were alternately polarized for the measurements of An and Ap. A mirror-symmetric detection system was used to cancel geometry-related systematic errors. From fits of the measured asymmetry angular distributions over the range of 53.4°<~θcm<~86.9°, the difference in the zero-crossing angles of the analyzing powers was determined to be 0.438°±0.054°(stat.)±0.051°(syst.) in the center-of-mass system. Using the experimentally determined slope of the analyzing power dA/dθ=(−1.35±0.05)×10−2 deg−1 (c.m.), this is equivalent to ΔA≡An−Ap=[59±7(stat.)±7(syst.)±2(syst.)]×10−4. The shape of ΔA(θ) in the vicinity of the zero-crossing angle has also been extracted. Predictions of nucleon-nucleon interaction models based on meson exchange agree well with the results.
(C=N) or (C=P) stands for polarized beam or target.
A new measurement of $\Delta\sigma_T$ for polarized neutrons transmitted through a polarized proton target at 16.2 MeV has been made. A polarized neutron beam was obtained from the $^{3}\rm{H}(d,\vec n)^{4}\rm{He}$ reaction; proton polarization over 90\% was achieved in a frozen spin target of 20 cm$^3$ volume. The measurement yielded the value $\Delta\sigma_T=(-126\pm21\pm14)$ mb. The result of a simple phase shift analysis for the $^3S_1-^3D_1$ mixing parameter $\epsilon_1$ is presented and compared with the theoretical potential model predictions.
No description provided.
The angles at which the n-p elastic scattering neutron analyzing power A00n0 crosses zero were measured with precision at four TRIUMF energies below 300 MeV. The mean interaction energies are also measured with greater precision than in previous experiments. The results are En=175.26±0.23 MeV, θzx=98.48°±0.28°; En=203.15±0.20 MeV, θzx=91.31°±0.18°; En=217.24±0.19 MeV, θzx=87.64°±0.18°; and En=261.00±0.16 MeV, θzx=80.18°±0.19°. After correction for charge symmetry breaking effects, the energy where the averaged neutron-proton analyzing power crosses zero at θzx=90° is found to be En=206.8±0.6 MeV. © 1996 The American Physical Society.
Polarized beam and target.
Polarized beam and target.
Polarized beam and target.
The differential cross sections for neutron-proton charge-exchange scattering have been measured for incident neutron momenta between 8 and 29 GeV /c and for four-momentum transfers | t | between 0.002 and 1.0 (GeV/ c ) 2 . A neutron beam with a broad momentum spectrum was scattered from a liquid hydrogen target. The momenta and scattering angles of the forward-scattered protons were measured by a spark-chamber magnet spectrometer. The flight times and scattering angles of the recoil neutrons were measured by a bank of thick scintillation counters. The efficiencies of the neutron counters were determined in a separate measurement. Absolute normalization of the data was obtained from a measurement of the diffraction dissociation of neutrons from carbon nuclei. Differential cross sections, based on ∼ 23 000 events, are presented for 9 different momenta. The shape of the differential cross sections and the momentum dependence are examined in detail.
No description provided.
No description provided.
No description provided.
The differential cross sections for neutron-proton charge-exchange scattering have been measured with high statistics in the region of momentum transfer squared 0.002 < | t | ⩽ 0.400 (GeV/ c ) 2 and for incident neutron momenta 9 < p ⩽ 23 GeV/ c .
No description provided.