Elastic π±−p, K−−p, and p¯−p scattering cross sections have been measured using three different experimental arrangements covering the c.m. angular regions ∼20°-120°, ∼135°-169°, and ∼165°-180° at incident momenta from 6 to 17 GeV/c. In the region 130°-180°, only π±−p scattering was measured. In the angular region near 180°, the energy dependences and shapes of the π−p backward peaks were determined up to crossed-momentum transfers of u∼−2 (GeV/c)2. At all energies, the π+−p backward peak had a sharp dip at u=−0.13 (GeV/c)2, with no similar effect in the π−−p case. Nearly complete angular distributions of π−−p elastic scattering from 20° to 180° have been obtained at 6 and 10 GeV/c. These results at 6 and 10 GeV/c as well as at 8 GeV/c reveal a sharp dip in π−−p scattering at t=−3 (GeV/c)2. Several structures in the form of dips or shoulders were seen in the p¯−p angular distributions also, with less pronounced structure observed in K−−p scattering. At fixed momentum transfer, all cross sections when expressed as dσdt appear to be decreasing with increasing energy.
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Differential cross sections for He3 + He3 elastic scattering have been measured at 18 angles from 12.5 to 45° (lab) at energies of 17.91, 20.00, 22.00, 24.00, 26.00, 28.00, and 30.00 MeV (lab). In addition, differential cross sections have been measured at intermediate energies from 19.00 to 32.00 MeV (lab) at angles of 20, 28, 36, and 45° (lab). The relative standard deviations of the data are generally less than 2%, and there is an additional standard deviation in the cross-section scale of 3%. The measurements are compared with theoretical calculations using the resonating-group method in the one-channel approximation. A broad resonance in the l=3 partial wave is predicted by the theory, and such a resonance has been observed in the present experiment. Differences between theory and experiment can be qualitatively understood as being caused principally by omission in the theory of reaction channels and noncentral forces. The effect of radial distortion in resonating-group calculations for the He3 + He3 system has also been investigated in an approximate manner. It is found that the effect can be quite significant for calculations of the energies of states in Be6 below the He3 + He3 threshold.
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Results are reported on K − -neutron interactions at c.m. energies near 2 GeV. The interactions are dominated by strong production of hyperon resonances, particularly Σ(1385), Λ(1405) and Λ(1520). Production cross sections and angular distributions are given for the Σ(1385), Λ(1405) and Λ(1520) and branching fractions to decay modes observed in the experiment are given for Σ(1385) and Λ(1520). The strong energy dependence of some features of the data suggests that s -channel effects are dominant.
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RESONANCE CROSS SECTIONS FOR <K- PI- P> FINAL STATE.
RESONANCE CROSS SECTIONS FOR <AK0 PI- N> FINAL STATE.
Cross sections for π − p→n π o at 5.9, 10.1 and 13.8 GeV/ c incident momentum are presented in the angular region from 180 o to u , the crossed four-momentum transfer squared, of −2(GeV) 2 and the energy dependence is discussed. The cross section for π − p→n η o integrated over the same angular region at 5.9 GeV/ c is also presented.
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We have studied the reaction e−+p→e−+π++n by detecting the final electron and pion in coincidence. Data are presented in the region of virtual photon mass squared from -0.18 to -1.2 GeV2, and virtual photoproduction center-of-mass energy and angle from 1.85 to 2.50 GeV and 0 to 20°, respectively.
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proton-beryllium TOTAL cross section ( 278 mb ) was used for normalization.
Proton-beryllium TOTAL (???) cross section ( 278 mb ) was used for normalization.
In a study of the production mechanism of quasi-two-body final states at the five incident π+ momenta 2.95, 3.2, 3.5, 3.75, and 4.08 GeV/c, approximately 40 000 events with four outgoing charged particles were investigated. The cross sections for the processes π+p→N*++ρ, π+p→N*++ω, π+p→N*++η, and π+p→N*++f have been measured as a function of the pion energy. The differential cross sections and the decay density-matrix elements are discussed in terms of one-meson-exchange models [with absorption (OPEA) and with form factor (OPEW)] and Regge models. For the N*++ρ and the N*++ω reactions, the joint-decay matrix elements are calculated. The formation of N*(2850) in the direct channel is also investigated.
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p−d elastic cross-section and polarization measurements are presented at an incident energy of 198 MeV, over the center-of-mass angular range 80° to 170°. The peak in the backward or pickup region is examined in terms of a simple nucleon-exchange parametrization.
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An experiment was done using the new accelerated polarized proton beam at the Argonne National Laboratory zero-gradient synchrotron and a polarized proton target. The total cross section for proton-proton scattering at 3.5 GeV/c was measured in the spin states ↑↑ and ↑↓ perpendicular to the beam direction. The two cross sections were found to be equal within the experimental error of ±5%.
TOTAL CROSS SECTION DIFFERENCE FOR PURE TRANSVERSE SPIN STATES.
We have measured ρ0, ω (combined) and ϕ electroproduction over a range of virtual-photon four-momentum Q2 from 0.4 to 2.2 GeV2 and for photon energies ν from 2.7 to 8.6 GeV. We find that the slope of the t (momentum transfer) dependence of the ρ0 and ω forward peak decreases with increasing Q2 to less than half of the photoproduction slope.
The cross section for virtual photon are derived from E- P cross section bydividing on the virtual-photon flux factor.