The cross section for photoproduction of π0 mesons was measured at a photon energy of 3 GeV and squared four-momentum transfer (t) of -0.1 to -1.2 (GeV/c)2 using plane-polarized photons. The asymmetry was found to be consistent with +1.0 for t values above -0.4 and below -1.1. For −0.4<~t<~−1.0 there is a dip in the asymmetry and at t=−0.6 it drops to 0.55 ± 0.15. This result precludes a simple Regge model with ω0 and B; a theoretical description requires Regge cuts or an ω′ exchange.
No description provided.
MIT PREP (1967).
The asymmetry A = (σ + −σ − ) (σ + +σ − ) of the reaction γ p↑↓ → π 0 p was measured at the Deutsches Elektronen Synchrotron DESY, Hamburg at a mean photon energy of 4.0 GeV in the four-momentum transfer range 0.2 (GeV/ c ) 2 ⩽ −t ⩽ 1.1 (GeV/ c ) 2 in steps of approximately 0.08 (GeV/ c ) 2 . The π 0 -meson and the proton were detected in coincidence. The asymmetry is compatible with zero in the t -range 0.2 (GeV/ c ) 2 ⩽ − t ⩽ 0.4 (GeV/ c ) 2 and negative in the t -range ⩾ 0.5 (GeV/ c ) 2 .
No description provided.
As part of a program to determine proton-proton elastic-scattering amplitudes, we have measured the spin-spin correlation parameter CNN at 6 GeV/c. Measurements were made over the |t| range of 0.08 to 1.4 (GeV/c)2 using a polarized beam and a polarized target at the Argonne National Laboratory Zero Gradient Synchrotron.
No description provided.
We present measurements for the baryon-exchange reaction π − p→ Λ K 0 at 5 GeV/ c over the range − u <2(GeV/ c ) 2 . The differential cross section is obtained from events produced on a liquid hydrogen target. These data are combined with events produced on a butanol polarized target and the parameters P , A , and R are then determined from an analysis of the decay angular distribution of the forward-going Λ. From our data it is possible to determine the magnitudes and the relative phase of the two invariant amplitudes A ′ and B . The consequences for the ratio B / A ′ are discussed in detail.
No description provided.
THE ERRORS QUOTED IN D(SIG)/DU DO NOT INCLUDE THE ERROR ASSIGNED TO THE OVERALL U-INDEPENDENT CORRECTIONS FACTOR (4.62 +- 0.36), OR OTHER POSSIBLE NORMALIZATION ERRORS.
No description provided.
The elastic cross section for proton proton scattering at 11.75 GeV/ c was measured at the Argonne ZGS using a 50% polarized target. In the range p ⊥ 2 =0.6 → 2.2 (GeV/ c ) 2 we obtained precise measurements of d σ d t(ij) for the ⇈ ⇊, and ⇅ initial spin states perpendicular to the scattering plane. We confirmed that the asymmetry parameter, A , decreases with energy in the diffraction peak, but is approximately energy-independent at large p ⊥ 2 . We found that the spin correlation parameter c nn acquires rather dramatic structure, and at large p ⊥ 2 seems to grow with energy.
No description provided.
We have made the first measurement of the spin-spin correlation parameter CSS in pp elastic scattering at 6 GeV/c over the |t| range from 0.05 to 1.5 (GeV/c)2. The measured CSS data points are all negative, and their absolute values increase with |t|. The results are compared with some existing attempts to describe the pp scattering process.
NUMERICAL VALUES OBTAINED FROM AUTHORS. MAGNETIC FIELD ALIGNMENT AND APERTURE EFFECTS MEAN THAT QUANTITY ACTUALLY MEASURED IS 0.98 CSS + 0.02 CNN - 0.12 CSL. SEE LATER NUMBERS IN THE RECORD OF I. P. AUER ET AL., PL 70B, 475 (1977).
We have measured the total cross-section difference for pp scattering in initial spin states parallel to the beam direction at beam momenta of 1.17, 1.47, 1.69, 1.97 and 2.49 GeV/ c . This measurement was done in a standard transmission experiment. A striking energy dependence is observed with a maximum difference of −16.9 mb at P lab = 1.47 GeV/ c .
PRELIMINARY RESULTS.
PRELIMINARY RESULTS.
None
POLARIZATION PARAMETER P(N000).
POLARIZATION PARAMETER A(00N0).
WOLFENSTEIN PARAMETER D(N0N0).
Using the polarized-beam facility at Argonne National Laboratory and a polarized proton target, simultaneous measurements of the spin parameter P and the spin correlation term CNN were made. Data were obtained and analyzed at beam momenta of 2, 3, 4, and 6 GeV/c in the momentum-transfer-squared interval 0.1≤|t|≤2.8 (GeV/c)2. A preliminary phase-shift analysis of the 2- and 3-GeV/c data is discussed and a comparison with predictions of a particular Regge-pole model at all four energies is made.
No description provided.
No description provided.
No description provided.
We measured the cross section for proton-proton elastic scattering at 11.75 GeV/c using the Zero Gradient Synchrotron 52% polarized proton beam and a 60% polarized proton target. We measured dσdt(ij) in the ↑↑, ↓↓, and ↑↓ initial spin states perpendicular to the scattering plane in the range P⊥2=2.0−3.6 (GeV/c)2. We found that the asymmetry parameter A decreases smoothly with increasing P⊥2 in this range, and that the spin-spin correlation parameter Cnn may have a minimum near P⊥2=3 (GeV/c)2.
No description provided.
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