Differential cross-sections for proton-proton elastic scattering have been measured covering the angular range from 50° to 90° c.m. at twelve incident momenta from 1.3 to 3.0 GeV/c. The angular distributions are quite smooth, but there is evidence of structure in the energy dependence of fixed-angle cross-sections at |t| ∼ 1 (GeV)2.
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The total cross section of γ rays in hydrogen resulting in hadron production, σT, has been measured over the energy range 265-4215 MeV. A tagging system with narrow energy bins was employed. Structure in the resonance region followed by a steady fall with energy has been observed and the results are analyzed. The forward amplitude of γ-proton scattering is evaluated, and its behavior in the Argand diagram studied as a function of energy. The relationships of the measurements to Regge-pole theory and the vector-dominance model are detailed.
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SPIN AVERAGED FORWARD COMPTON SCATTERING AMPLITUDE. IM(AMP) WAS CALCULATED VIA THE OPTICAL THEOREM FROM A SMOOTH FIT TO THE DATA, AND USED IN THE DISPERSION RELATION TO CALCULATE RE(AMP). AT THRESHOLD THE THOMSON AMPLITUDE IS -3.0 MUB*GEV.
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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.
The total hadronic cross section, σ T has been measured for tagged γ -rays, using electron beams in the GeV range, and narrow energy bins. Preliminary data are given covering the γ -energy region 275 MeV-1850 MeV, where interesting structure characteristics are observed.
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The elastic scattering of 3.6 GeV/ c π + mesons by protons has been studied in a hydrogen bubble chamber experiment. The elastic cross section has a measured value of 7.07 ± 0.20 mb. The forward diffraction peak has been fitted in the region 0.05 ≦ − t ≦ 0.6 (GeV/ c ) 2 by a form (d σ /d t ) = Ae Bt , where A = 46.5 ± 1.8 mb/(GeV/ c ) 2 and B = 6.85 ± 0.20 (GeV/ c ) −2 . From this fit and the optical theorem, the magnitude of the ratio of real to imaginary forward amplitude is 0.39 ± 0.06, in reasonable agreement with dispersion relation calculations and simple Regge model predictions.
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Total cross sections for π−p→ΛK0 have been measured using optical spark chambers from threshold to 1.13−GeVc beam momentum in 19−MeVc intervals, but with a 1−MeVc resolution in the regions of the ΛK and ΣK thresholds. The behavior near ΛK threshold indicates a significant s-wave contribution, but this experiment is unable to resolve any cusplike behavior in the region of the ΣK thresholds. The cross section shows a broad peak in the vicinity of 1.05−GeVc beam momentum.
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A study of the A2+ mass spectrum in π+p interactions at 3.7 GeVc is presented. For a cut of t′=0.1−2.0 GeV2 and on eliminating the Δ++ we find that the three-pion mass spectrum in the A2+ region is fitted by the dipole formula with a confidence level of 53% and a single Breit-Wigner formula with a confidence level of 11%. Our result thus favors A2+ splitting although a single Breit-Wigner fit cannot be ruled out. We also report the A2+ decay branching fractions measured over all t′ values. They are 0.78 ± 0.05, 0.15 ± 0.04, 0.06 ± 0.03, and < 0.02 for ρπ, ηπ, KK¯, and η′π, respectively, in good agreement with other experiments.
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Electron-proton elastic scattering cross sections have been measured at four-momentum transfers between 1.0 and 3.0 (GeV/ c ) 2 and at electron scattering angles between 10° and 20° and at about 86° in the laboratory. The proton electromagnetic form factors G E and G M were determined. The results indicate that G E ( q 2 ) decreases faster with increasing q 2 than G M ( q 2 ).
Axis error includes +- 2.5/2.5 contribution (Due to counting statisticss, separation of elastic events, beam monitoring, incident energy, scattering angle, proton absorption, solid angle, target length and density).
CONST(NAME=MU) is the magnetic moment.
An experiment has been carried out to determine the imaginary part of the two-photon exchange amplitude by measuring the polarisation of the recoil proton in elastic electron-proton scattering. The polirisation was found to be −0.006 ± 0.030 at q 2 = 1.3 (GeV/ c ) 2 , +0.052 ± 0.55 at 1.5 (GeV/ c ) 2 and +0.065 ± 0.087 at 1.9 (GeV/ c ) 2 .
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The reaction e+d→e′+n+p was studied at electron scattering angles θ ⩽ 35° for four-momentum transfers of 0.39, 0.565 and 0.78 (GeV/ c ) 2 . By recording electron-neutron and electron-proton coincidences, the ratio of the electron scattering cross sections on quasi-free neutrons and protons was determined. An estimate of the binding effects, based on a Chew-Low-extrapolation, was made. Values for the neutron form factors were derived.
Axis error includes +- 0.0/0.0 contribution (Due to the different effective solid angles for neutron and proton detection in the counters).
No description provided.
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