None
Axis error includes +- 0.0/0.0 contribution (?////UNCERTAINTY IN DATA PROCESSING).
Axis error includes +- 0.0/0.0 contribution (?////UNCERTAINTY IN DATA PROCESSING).
No description provided.
The total electromagnetic cross sections of g-rays in hydrogen and deuterium have been measured over the energy range 265–4215 MeV using a photon tagging system. From these measurements, the total pair production cross sections are obtained, and the results are found to be in good agreement with the predictions of Jost, Luttinger and Slotnick.
Axis error includes +- 1/1 contribution.
Axis error includes +- 1/1 contribution.
The total cross section for photoproduction of hadrons on the deutron, σ T d , has been measured for photon energies in the range 0.265–40215 GeV. From this, using results for the photon total cross section, obtained previously with the same apparatus, the neutron total cross section has been determined in the resonance region. The resonant structure is found to be quite different from that for the proton. Thereafter the neutron cross section falls off steadily with energy, and the values obtained are consistently lower than those for the proton. Forward scattering amplitudes have been evaluated for the deuteron.
No description provided.
RESONANCE REGION. UNSMEARING CORRECTION APPLIED, GLAUBER CORRECTION NEGLIGIBLE.
HIGHER ENERGY CROSS SECTIONS, IN 200 MEV BINS. OVERALL 3 PCT SYSTEMATIC ERROR IN ADDITION TO QUOTED STATISTICAL ERRORS. NEUTRON/PROTON CROSS SECTION RATIO HAS MEAN VALUE OF 0.94 +- 0.01.
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.
No description provided.
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.
Using the colliding beam machine, VEPP-2, the excitation curve of the ø-meson resonance was investigated in the three main decay modes. The resonance parameters obtained are the width, the total cross-section and the branching ratios. Namely: Γ = (4.67 ± 0.42) Mev B ( K + K − ) = (54.0 ± 3,4) % σ o = (3.96 ± 0.35) μB B ( K o s K O L ) = (25.7 ±3,0) % B ( e + e − = (2,81 ± 0.25) × 10 −4 B ( π + π − π o ) = (20.3 ± 4,2) %
BREIT-WIGNER FITS TO DATA POINTS AT 9 ENERGIES AROUND PHI FOR EACH CHANNEL. PEAK CROSS SECTIONS QUOTED.
PION FORM FACTOR AT PHI MASS, ALLOWING FOR POSSIBLE INTERFERENCE.
None
No description provided.
The differential cross-section for π+ photoproduction from hydrogen by γ-rays of laboratory energy 187 MeV has been measured at four angles. Two identical counter systems, designed to detect low energy pions unambiguosly in intense electron and γ-ray backgrounds, were used in conjunction with a cylindrical liquid hydrogen target, of very low boil-off rate. The cross-sections at laboratory angles of 39.2°, 66.7°, 111.6°, and 134° are 7.49±0.47, 8.10±0.57, 8.36±0.61 and 9.54±0.61, ·10−30cm2/sr, respectively, where the assigned errors refer only to the relative values. The absolute cross-sections are in substantial agreement with the dispersion theory and confirm the front to back asymmetry.
No description provided.
The variation of the differential cross section for π+ photoproduction from hydrogen, with γ-ray energy, has been examined at a laboratory angle of 58° to the γ-ray beam. A thin hydrogen target, and a counter system designed to eliminate random events, have been employed. Mean values for the differential cross section dσdΩ at γ-ray energies of 162, 168, 175, and 192 Mev are 5.42±0.38, 5.77±0.41, 6.74±0.47, and 8.22±0.58 μb/sr, respectively, where the error limits refer to relative values. The results substantiate the rising trend of the interaction quantity {(dσdΩ)(μ2pε)(1+ωM)2} near threshold, in accord with dispersion theory; and the absolute cross sections are compatible with a threshold value for a0+ near 20 μb/ steradian, consistent with findings in related pion work.
No description provided.
Forum