The asymmetry A LL for pp elastic scattering has been measured at 650 and 800 MeV in the region of Coulomb-nuclear interference. The real part of the double-spin-flip amplitude extracted from these data completes our determination of the forward pp scattering amplitudes at these energies. Comparison with the predictions of forward dispersion relations reveals a discrepancy in the spin-dependent channels at 650 MeV.
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We present first measurements of total cross section differences Δσ T and Δσ L for a polarized neutron beam transmitted through a polarized proton target. Measurements were carried out at SATURNE II, at 0.63, 0.88, 0.98 and 1.08 GeV. The results are compared with Δσ L data points deduced from p-d and p-p transmission experiments, and with phase shift analyses predictions. The present results together with the corresponding pp data yield two of the three spin dependent forward scattering amplitudes for isospin I =0.
Statistical errors are statistics and random fluctuations. Systematic error contains uncertainties in beam and target polarizations, hydrogen content of the target, and residual error due to misalignment.
We measured the analyzing power A and the spin-spin correlation parameter Ann, in large-P⊥2 proton-proton elastic scattering, using a polarized-proton target and the polarized-proton beam at the Brookhaven Alternating-Gradient Synchrotron. We also used our polarimeter to measure A at small P⊥2 at 13 GeV with good precision and found some deviation from the expected 1Plab behavior. At 18.5 GeV/c we found Ann=(−2±16)% at P⊥2=4.7 (GeV/c)2. Comparison with lower-energy data from the Argonne Zero-Gradient Synchrotron shows a sharp and surprising energy dependence for Ann at large P⊥2.
POL is error weighted average of polarized beam and target measurements.
POL is error-weighted average of polarized beam and target measurements.
POL is error-weighted average of polarized beam and target measurement.
Using the new Brookhaven Alternating Gradient Synchrotron polarized proton beam and our polarized proton target, we measured the spin-spin correlation parameter Ann in 16.5-GeV/c proton-proton elastic scattering. We found an Ann of (6.1±3.0)% at P⊥2=2.2 (GeV/c)2. We also measured the analyzing power A in two independent ways, providing a good test of possible experimental errors. Comparing our new data with 12-GeV Argonne Zero Gradient Synchrotron data shows no evidence for strong energy dependence in Ann in this medium-P⊥2 region.
ERROR CONTAINS BOTH SYSTEMATIC AND STATISTICAL UNCERTAINTY.
New pp measurements of Delta sigma L and Delta sigma T between 200 and 520 MeV disagree with earlier Argonne data, and resolve discrepancies with inelastic data, phase-shift analysis and forward dispersion relations.
TOTAL CROSS SECTION DIFFERENCE FOR PURE TRANSVERSE SPIN STATES (ANTIPARALLEL MINUS PARALLEL).
TOTAL CROSS SECTION DIFFERENCE FOR PURE LONGITUDINAL SPIN STATES (ANTIPARALLEL MINUS PARALLEL).
We have measured the asymmetry parameter A and the spin correlation parameter A nn in pp elastic scattering, using the Argonne ZGS polarized proton beam and a polarized proton target. Angular distributions of A and A nn for | t | ≳ 0.2 (GeV/ c ) 2 were obtained at eight momenta between 1.10 and 2 if 2.75 GeV/ c . We find significant structure in both the energy and t -dependence of A nn at these energies. At p lab ≈ 1.34 GeV/ c A nn reaches a very large value of about 0.8–0.9 near θ cm = 90°.
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DATA AVERAGED FOR TWO DIRECTIONS OF TARGET POLARIZATION.
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The reaction\(\bar pp \to \bar \Lambda \Lambda \) has been studied in a bubble chamber experiment at eight incident momenta between 1.50 and 2.06 GeV/c. The differential cross-section, the polarization and the spin correlation coefficients have been measured. They have been compared with the prediction of two theoretical models: the K-meson conspiracy and the exchange of the K*K** degenerate trajectory associated with a Regge cut. The latter model gives the best representation of the data.
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POLARIZATION AND SPIN CORRELATION COEFFICIENTS. AVERAGED OVER ALL ANGLES. SEE PAPER FOR DEFINITIONS, MORE DETAILS AND POSSIBLE T-DEPENDENCE.
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=0.60−1.0 (GeV/c)2 using a 65% polarized target and a 75% polarized proton beam of intensity 3 × 109 protons/pulse. The polarization of the recoil proton was simultaneously measured 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 our largest P⊥2. Parity invariance implies that the eight single-flip transversity cross sections are zero, so our data gives the magnitudes of the eight remaining pure spin cross sections where all spins are measured. We find that the four double-flip transversity cross sections are nonzero.
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THE FIVE INDEPENDENT PURE FOUR-SPIN CROSS SECTIONS AS DERIVED FROM THE EIGHT MEASURED THREE-SPIN CROSS SECTIONS ASSUMING P AND T INVARIANCE. THE ABSOLUTE DIFFERENTIAL CROSS SECTION VALUES ASSUME THAT THE SPIN-AVERAGED D(SIG)/DT IS 2.25, 1.17, 0.365 AND 0.167 MB/GEV**2 FOR EACH VALUE OF PT**2 RESPECTIVELY.
WOLFENSTEIN PARAMETERS. POL(NAME=A) IS (N000) OR (0N00), THE ANALYZING POWER AVERAGED OVER TARGET OR BEAM POLARIZATION. POL(NAME=P) IS (00N0), THE POLARIZATION PARAMETER. TIME-REVERSAL INVARIANCE REQUIRES THAT P = A. POL.POL(NAME=CNN) IS (NN00) USING T-INVARIANCE. POL.POL(NAME=DNN) IS (0N0N). POL.POL(NAME=KNN) IS (N00N). POL.POL(NAME=C3N) IS A COMPONENT OF THE TRIPLE SPIN CORRELATION TENSOR. PARITY INVARIANCE REQUIRES THAT C3N = P.
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.
No description provided.
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