The differential elastic p−p scattering cross section was measured at 6 GeV/c at the Argonne Zero Gradient Synchrotron in the range p⊥2 = 0.6−1.0 (GeV/c)2 using a 65%-polarized target and a 75%-polarized extracted beam of intensity 3 × 109 protons/pulse. We simultaneously measured the polarization of the recoil proton with a well-calibrated carbon-target polarimeter. All three polarizations were measured perpendicular to the horizontal scattering plane. Our results indicate that P and T invariance are both obeyed to good precision even at large p⊥2. Parity invariance implies that the eight single-flip transversity cross sections are zero, so our data give the relative magnitudes of the eight remaining pure spin cross sections where all spins are measured. We find that the double-flip transversity cross sections are nonzero.
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Results are presented from an experiment designed to make the first systematic study of the depolarization parameter in elastic proton-proton scattering at high energies. Measurements were made at 3.0 and 6.0 GeV/c at |t| values extending to 1.7 (GeV/c)2 at the higher momentum. A high-intensity unpolarized proton beam was incident on a polarized proton target and the polarization of the elastically scattered recoil protons was determined with a carbon analyzer. The results are discussed in the framework of optical and exchange models.
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The spin rotation parameter R has been measured at CERN, for π ± p at 6 GeV c and for π − p at 16 GeV c , with t ranging from −0.19 to −0.51 ( GeV c ) 2 . The parameter A was measured for π − p at 6 GeV c in the interval between t =−0.19 and minus;0.41 ( GeV c ) 2 . The averaged values are the following; R (+6) =−0.08±0.04, R (−6) =−0.23±0.05 and R (−16) =−0.23±0.05. The values obtained for A are close to +1.
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Differential cross sections for π − p and pp elastic scattering have been measured at incident momenta ranging from 30 to 345 GeV and in the t range 0.002 (GeV/ c ) 2 ⩽ | t | ⩽ 0.04 (GeV/ c ) 2 . From the analysis of the data, the ratio ϱ ( t = 0) of the real to the imaginary parts of the forward scattering amplitude was determined together with the logarithmic slope b of the diffraction cone.
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Differential cross sections in the t -range between 0.02 and 1.5 GeV 2 have been measured for the elastic scattering of particles and antiparticles on protons at 6.4, 10.4 and 14 GeV for K ± p and 10.4 GeV for π ± p and p ± p . Large statistics have been achieved and systematic uncertainties have been minimized. The relative systematic uncertainty between particle and antiparticle data is less than 0.5%. Accurate measurements of the position of the first crossover between particle and antiparticle differential cross sections have been performed. As the energy increases from 6.4 to 14 GeV the K ± p crossover moves to smaller values by 0.010 GeV 2 with a statistical error of 0.006 GeV 2 and a systematic uncertainty of 0.005 GeV 2 . The crossover positions at 10.4 GeV for π ± , K ± and p ± scale approximately with the interaction radii.
CROSSOVER POSITION IS -T = 0.209 +- 0.004 (DSYS = 0.003) GEV**2.
CROSSOVER POSITION IS -T = 0.209 +- 0.004 (DSYS = 0.003) GEV**2. SMALL ANGLE CROSS SECTIONS IN SMALLER T-BINS.
CROSSOVER POSITION IS -T = 0.211 +- 0.004 (DSYS = 0.0025) GEV**2.
Results are presented from experiment WA7 at the CERN SPS, which has measured the elastic differential cross sections of π ± p, K ± p, p p and pp at incident momen ta of 20, 30 and 50 GeV/ c . The measurements cover the momentum transfer range 0.5 < | t | < 8 (GeV/ c ) 2 , corresponding to c.m. scattering angles between 10° and 50°. The experimental set-up, trigger logic and data analysis are described. The experimental results are compared with existing meson-proton and nucleon-proton data at lower and higher energies covering the medium- and large-| t | region. Some prominent models and their predictions for elastic scattering at WA7 energies and beyond are reviewed, with emphasis on geometrical scaling, factorizing eikonal models, lowest-order QCD and other dynamical exchange-type models. Results for p p two-body annihilation into π − π + and K − K + at 30 and 50 GeV/ c , obtained in parallel with the elastic p p data, are also presented.
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Measurements at 18 beam kinetic energies between 1975 and 2795 MeV and at 795 MeV are reported for the pp elastic-scattering single spin parameter Aooon=Aoono=AN=P. The c.m. angular range is typically 60–100°. These results are compared to previous data from Saturne II and other accelerators. A search for energy-dependent structure at fixed c.m. angles is performed, but no rapid changes are observed.
Measured values of the P P analysing power at kinetic energy 0.795 GeV. Therelative and additive systematic errors are +- 0.018 and 0.0007.
Measured values of the P P analysing power at kinetic energy 1.975 GeV. Therelative and additive systematic errors are +- 0.045 and 0.002.
Measured values of the P P analysing power at kinetic energy 2.035 GeV fromrun I. The relative and additive systematic errors are +- 0.044 and 0.002.
Experimental results are presented for the pp elastic-scattering single spin observable Aoono=Aooon=AN=P, or the analyzing power, at 19 beam kinetic energies between 1795 and 2235 MeV. The typical c.m. angular range is 60–100°. The measurements were performed at Saturne II with a vertically polarized beam and target (transverse to the beam direction and scattering plane), a magnetic spectrometer and a recoil detector, both instrumented with multiwire proportional chambers, and beam polarimeters.
Measurement values of the P P analysing power at kinetic energy 1.795 GeV. The relative and additive systematic errors are +- 0.106 and 0.003.
Measurement values of the P P analysing power at kinetic energy 1.845 GeV. The relative and additive systematic errors are +- 0.068 and 0.001.
Measurement values of the P P analysing power at kinetic energy 1.935 GeV. The relative and additive systematic errors are +- 0.091 and 0.003.
Results are presented on π + p and K + p elastic scattering at 250 GeV/ c , the highest momentum so far reached for positive meson beams. The experiment (NA22) was performed with the european hybrid spectrometer. The π + p elastic cross section stays constant with energy while the K + p cross section increases.
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ERRORS IN ELASTIC CROSS SECTIONS INCLUDE SYSTEMATIC ERRORS.
The angular distributions of the reactions K - p → K - p and K - p → K K 0 n have been measured at 23 incident K - momenta between 1.136 and 1.798 ifGeV/c using the bubble chamber technique. These data, together with other published data on the same reactions, including K - p polarisations, K̄N total cross sections, and measurements of Re ƒ(0)/ Im ƒ(0) , have been analysed in terms of partial-wave amplitudes. Resonance behaviour is confirmed for the P 03 partial wave at 1890 MeV. The resonance parameters of the F 15 (1915), F 17 (2030) and G 07 (2100) have been redetermined. No evidence has been found for new resonances coupling significantly to K K N in the energy region explored.
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