The ratio of the analysing powers for quasi-elastic pp scattering in carbon and for elastic scattering on free protons was measured fromT = 0.52 to 2.8 GeV by scattering of the SATURNE II polarized proton beam on carbon and CH2. It was found to have a maximum at about 0.8 GeV. The energy dependence for quasielastic scattering on carbon had not been measured before above 1 GeV. The observed effect was not expected from simple models.
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Excitation functions AN(pp,Θc.m.) of the analyzing power in pp→ elastic scattering have been measured with a polarized atomic hydrogen target for projectile momenta pp between 1000 and 3300 MeV/ c. The experiment was performed for scattering angles 30°≤Θc.m.≤90° using the recirculating beam of the proton storage ring COSY during acceleration. The resulting excitation functions and angular distributions of high internal consistency have significant impact on the recent phase shift solution SAID SP99, in particular, on the spin triplet phase shifts between 1000 and 1800 MeV, and demonstrate the limited predictive power of single-energy phase shift solutions at these energies.
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We report measurements of the proton form factors GEp and GMp extracted from elastic scattering in the range 1≤Q2≤3 (GeV/c)2 with total uncertainties < 15% in GEp and < 3% in GMp. Comparisons are made to theoretical models, including those based on perturbative QCD, vector-meson dominance, QCD sum rules, and diquark constituents in the proton. The results for GEp are somewhat larger than indicated by most theoretical parametrizations, and the ratios of the Pauli and Dirac form factors Q2(F2pF1p) are lower in value and demonstrate a weaker Q2 dependence than those predictions. A global extraction of the elastic form factors from several experiments in the range 0.1 0.1<Q2<10 (GeV/c)2 is also presented.
Point-to-point systematic uncertainty is 0.5%, overall normailzation uncertainty is 1.9%.
Point-to-point systematic uncertainty is 0.5%, overall normailzation uncertainty is 1.9%.
Point-to-point systematic uncertainty is 0.5%, overall normailzation uncertainty is 1.9%.
Measurements of the semileptonic weak-neutral-current reactions νμp→νμp and ν¯μp→ν¯μp are presented. The experiment was performed using a 170-metric-ton high-resolution target detector in the BNL wide-band neutrino beam. High-statistics samples yield the absolute differential cross sections dσ(νμp)/dQ2 and dσ(ν¯μp)/dQ2. A measurement of the axial-vector form factor GA(Q2) is also presented. The results are in good agreement with the standard model SU(2)×U(1). The weak-neutral-current parameter sin2thetaW is determined to be sin2θW=0.220±0.016(stat)−0.031+0.023(syst).
Errors contain both statistics and systematics, except for additional overall normalisation error given above. Neutrino energy is 0 to 5 GeV with peak at 0.8 Gev.
The total cross section difference Δα L (pp) for proton-proton scattering with beam and target polarized longitudinally parallel and antiparallel, respectively, has been measured using the polarized proton beam from SATURNE II and a frozen spin polarized proton target. The beam polarization was reversed from pulse to pulse, and at each energy Δα L was measured for both signs of target polarization. The data below 800 MeV confirm the previously observed structures. The cross section difference is found to change by 8.0 ± 0.5 mb between 520 MeV and 760 MeV. At the higher energies the results show no indication for similar structures or for a change of the sign of Δα L .
ERRORS INCLUDE UNCERTAINTY IN THE BEAM POLARIZATION.
The differential cross sections for γp→γp and γp→π0p have been measured for incident photon energies in the range of 2 to 6 GeV and for |t| ranging from 0.7 to 4.3 GeV2. This corresponds to a center-of-mass angle range of 45° to 128°. The energy dependence of the data is compared to that predicted by several parton models.
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We present a series of numerical and statistical techniques for interpolating and combining ("amalgamating") data from meson-nucleon scattering experiments. These techniques have been extensively applied to πp elastic and charge-exchange differential-cross-section and polarization data in the resonance region. The amalgamation is done by fitting a momentum- and angle-dependent interpolating surface to the data over a moderately narrow momentum range, typically ∼150 MeV/c, using the interpolating surface to shift data in a narrower central momentum region into fixed angular bins at a predetermined central momentum, and then statistically combining the data in each bin. The fitting procedure takes into account normalization errors, momentum calibration errors, momentum resolution, electromagnetic corrections, threshold structure, and inconsistencies among the data. The full covariance matrix of the amalgamated data is calculated, including contributions of statistical error, systematic error, and interpolation error. Techniques are presented for extracting from the covariance matrix information on the collective statistical fluctuations which correlate the errors of the amalgamated data. These fluctuations are described in terms of "correlation vectors" which facilitate the use of the amalgamated data as input for resonance-region phenomenology.
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We measured d σ d t(90° cm ) for ↑+ p ↑→ p + p from 1.75 to 5.5 GeV/ c , using the Argonne zero-gradient synchrotron 70% polarized proton beam and a 70% polarized proton target. We found that the spin-spin correlation parameter. A nn , equals 60% at low energy, then drops sharply to about 10% near 3.5 GeV/ c , and remains constant up to 5.5 GeV/ c .
ANALYZING POWER. QUOTED ERRORS DUE TO 4.3 PCT POINT TO POINT RELATIVE ERROR.
THE SPIN-SPIN CORRELATION PARAMETER CNN IS NOW DENOTED BY ANN ACCORDING TO THE NEW ANN ARBOR CONVENTION.
Antiproton-proton total elastic cross sections at 21 incident momenta in the range 0.69 to 2.43 GeV/ c have been deduced by combining p̄p elastic differential cross sections over a c.m. angular range −0.95 ⩽ cos θ ∗ ⩽ 0.93 with forward elastic cross sections derived from recent real-part measurements and p̄p total cross sections. Two bumps are observed, at M 1 ⋍ 2.155 and M 2 ⋍ 2.345 GeV /c 2 , having widths of Г 1 ∼ 0.135 and Г 2 ∼ 0.135 GeV /c 2 . Corresponding structures in other p̄p reaction channels are discussed.
Axis error includes +- 4/4 contribution.
Measurements have been made of the differential cross section for p p elastic scattering over a c.m. angular range −0.95 ⩽ cos θ ∗ ⩽ 0.93 at 21 incident antiproton momenta between 0.69 GeV/ c and 2.43 GeV/ c (c.m. energy 1.96–2.58 GeV). About 10 5 events were obtained at each momentum. The results are discussed primarily in terms of the formation of s -channel resonances in the T and U mass regions, and within the context of the optical model of Frahn and Venter.
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