R. H. Jeppesen

Measurements of ΔσL (np) between 500 and 800 MeV

Abstract A measurement of Δσ L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states, is described. Data were taken for five energies between 500 and 800 MeV, with statistical errors of ≈ 1.5 mb and an estimated normalization error of 6%. The data, combined with other results, show some evidence for an elastic I =0 spin-singlet resonance with mass ∼ 2213 MeV and width ∼ 74 MeV, or a coupled-triplet resonance with similar mass and width.

Quick polarization analyzer (QPAN)

Abstract A high count rate polarimeter for the measurement and monitoring of the polarization of an intermediate energy neutron beam has been developed. The device, QPAN, consists of a double arm telescope with adjustable copper absorbers. The asymmetry of the protons scattered from the liquid hydrogen (LH2) target is calculated from the count differential between two arms, positioned above and below the beam.

A neutron hodoscope for medium energy np scattering experiments

Abstract A 24-element plastic scintillation counter hodoscope for np elastic and total cross section measurements at LAMPF is described. Details of construction, electronics, calibration with cosmic ray muons, and a determination of absolute detection efficiency at 289 and 435 MeV are presented.

Measurements of Spin-Correlation Parameters all and Asl for P-]P-]-]Pid between 500 and 800 Mev

Measurements of A/sub L/L between 500 and 800 MeV and spin dependent cross sections derived from these measurements are presented for the reaction pp..--> pi..d at c.m. angles theta/sub ..pi../( of 50/sup 0/, 70/sup 0/, and 90/sup 0/. Angular distributions for A/sub S/L are also presented for energies 500, 650, and 800 MeV. These are the first measurements of spin-correlation parameters in this channel above 590 MeV, and are in substantial disagreement with theoretical predictions of the triplet amplitudes above 600 MeV.

Measurements of spin-correlation parametersALLandASLforp→p→→πdbetween 500 and 800 MeV

Measurements of A/sub L/L between 500 and 800 MeV and spin dependent cross sections derived from these measurements are presented for the reaction pp..--> pi..d at c.m. angles theta/sub ..pi../( of 50/sup 0/, 70/sup 0/, and 90/sup 0/. Angular distributions for A/sub S/L are also presented for energies 500, 650, and 800 MeV. These are the first measurements of spin-correlation parameters in this channel above 590 MeV, and are in substantial disagreement with theoretical predictions of the triplet amplitudes above 600 MeV.

Measurements of spin-correlation parameters A/sub L/L and A/sub S/L for pp. --> pi. d between 500 and 800 MeV

Measurements of A/sub L/L between 500 and 800 MeV and spin dependent cross sections derived from these measurements are presented for the reaction pp..--> pi..d at c.m. angles theta/sub ..pi../( of 50/sup 0/, 70/sup 0/, and 90/sup 0/. Angular distributions for A/sub S/L are also presented for energies 500, 650, and 800 MeV. These are the first measurements of spin-correlation parameters in this channel above 590 MeV, and are in substantial disagreement with theoretical predictions of the triplet amplitudes above 600 MeV.

Forward amplitudes for π* on Al, Ca, Cu, Sn, Ho, and Pb in the energy range 65–215 MeV

Measurements have been made of the attenuation cross section, σ (Ω), for both π+ and π− projectiles on Al, 40Ca, Cu, Sn, Ho, and Pb nuclei. The measurements were made over a range of energies including 63, 115, 140, 165, and 215 MeV. A new method of analyzing transmission experiment data, proposed by Cooper and Johnson1, has been used to extract both the real and the imaginary parts of a forward scattering amplitude fN(O), where fN(O) is defined to be the limit as Ω→O of F(Ω)−fc(Ω). F(Ω) is the full elastic scattering amplitude and fc(Ω) is the relativistic point Coulomb scattering amplitude2. The values of fN(O) may be compared with forward amplitudes from theoretical models.A sample of the data is shown in Fig. 1 for Tπ=165 MeV. Figures 1a and 1b are the A dependence of the real and imaginary parts of fN(O), respectively. Due to isospin invariance, the following relations might be expected to hold: Re fπ+N(O =Re fπ−N(O and Im fπ+N(O) =Im fπ+N(O . These symmetries are broken by the unequal number of prot...