Measurements of the polarization parameters and angular distributions are reported for π±p elastic scattering at 100 GeV/c and for pp elastic scattering at 100- and 300-GeV/c incident momentum. The π±p data cover the kinematic range 0.18≤−t≤1.10 GeV2 and are in agreement with current Regge-model predictions. The pp data cover the kinematic range 0.15≤−t≤1.10 GeV2 and 0.15≤−t≤2.00 GeV2 at 100 and 300 GeV/c, respectively, and are found to be consistent with absorption-model predictions.
THESE ANGULAR DISTRIBUTIONS AND POLARIZATION PARAMETERS ARE TABULATED IN THE RECORD OF THE EARLIER BRIEF REPORT OF THIS EXPERIMENT USING PION BEAMS: I. P. AUER ET AL., PRL 39, 313 (1977).
THESE ANGULAR DISTRIBUTIONS AND POLARIZATION PARAMETERS ARE TABULATED IN THE RECORD OF THE EARLIER BRIEF REPORT OF THIS EXPERIMENT USING A PROTON BEAM: J. H. SNYDER ET AL., PRL 41, 781 (1978) AND PRL 41, 1256(E) (1978).
Polarization in π − p elastic scattering, with emphasis over the backward region, has been measured at 2.93 and 3.25 GeV/ c . We observe large changes in polarization compared with existing data above and below these energies. Our data may be useful in determining the properties of resonances and in understanding baryon exchanges.
THESE DATA, TOGETHER WITH THE FORWARD SCATTERING POLARIZATION MEASUREMENTS, ARE TABULATED IN THE RECORD OF P. AUER ET AL., PRL 37, 83 (1976).
Polarization in π−p elastic scattering, with emphasis in the region around the secondary dip and also θc.m.=90°, has been measured at 2.93 and 3.25 GeV/c. We observe an interesting sign change in this angular region.
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We have made measurements of polarization in π−p elastic scattering, with emphasis over the backward region, at 1.60 to 2.28 GeVc. The results indicate the absence of u-channel dominance in the backward region, as was observed in the case of π+p scattering. Comparisons have been made with predictions of various phase-shift analyses which show that the agreement is generally very poor in the backward region.
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We have measured the polarization for elastic scattering in the reaction π−p→π−p at 2.93 and 3.25 GeV/c using a polarized proton target and multiwire proportional chambers (MWPC's) with emphasis on large-angle scattering. Events were selected by fast scintillation-counter logic. Beam trajectories were measured with four MWPC's and the scattered-particle angles were measured with one or two MWPC's; elastic events were determined by coplanarity and angle-angle correlations. The polarization is in agreement with previous measurements below |t|=2.0 (GeV/c)2, and crosses from negative to positive near the secondary dip in the differential cross section dσdt. In the backward region, an energy dependence appears with the polarization being large and negative at 2.93 GeV/c and consistent with zero at 3.25 GeV/c.
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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.
We measured dσdt for p+p→p+p at 11.75 GeV/c using the zero-gradient synchrotron 70% polarized-proton beam and a 65% polarized-proton target. We obtained the spin-orbit asymmetry parameter A and the spin-spin correlation parameter Cm out to P⊥2=4.2 (GeV/c)2. We found that A drops smoothly towards zero, but that Cnn increases abruptly near P⊥2=3.6 (GeV/c)2, where the exp(−1.4P⊥2) component of elastic scattering becomes dominant. This suggests that large-P⊥2 "hard" elastic scattering may occur mostly when the two proton spins are parallel.
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We have measured the spin-spin correlation parameter CNN at 2, 3, 4, and 6 GeV/c over the |t| range of 0.1 to 2.0 (GeV/c)2 and have observed a striking energy and |t| dependence in CNN. Polarization data were simultaneously collected and are compared to previous results.
CNN PARAMETER MEASURED.
We measured the differential cross section for proton-proton elastic scattering at 6 GeV/c, with both initial spins oriented normal to the scattering plane. The analyzing power A shows significant structure with a large broad peak reaching about 24% near P⊥2=1.6 (GeV/c)2. The spin-spin correlation parameter Ann exhibits more dramatic structure, with a small but very sharp peak rising rapidly to about 13% at 90°c.m.. This sharp peak may be caused by particle-identity effects.
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The energy dependence of the spin-parallel and spin-antiparallel cross sections for p↑+p↑→p+p at 90°c.m. was measured for beam momenta between 6 and 12.75 GeV/c. The ratio (dσdt)parallel:(dσdt)antiparallel at 90° is about 1.2 up to 8 GeV/c and then increases rapidly to a value of almost 4 near 11 GeV/c. Our data indicate that this ratio may depend only on the variable P⊥2, and suggests that the ratio may reach a limiting value of about 4 for large P⊥2.
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