The polarized target asymmetry parameter has been measured for single π o photoproduction from hydrogen at 4 GeV and values of four-momentum transfer squared between −0.15 (GeV/ c ) 2 and −1.8 (GeV/ c ) 2 .
Axis error includes +- 0.0/0.0 contribution (?////).
The total cross section and the differential cross sections of the reactions π + d →π + d (elastic scattering) →π + pn (inelastic scattering) →π 0 pp (charge exchange scattering) →γ pp (radiative absorption) → pp , (non-radiative absorption) have been measured using 85 000 pictures of 290 MeV/ c positive pions in the 38 cm Princeton-Pennsylvania bubble chamber. The elastic, inelastic and charge exchange scattering data are more complete than any previous data in this energy range.
FOUND BY EXTRAPOLATION OF PARTIAL CROSS SECTION TO ZERO SOLID ANGLE.
TOTAL NUMBER EVENTS= 3400.
No description provided.
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.
We have measured the production and decay angular distributions of the reaction π + p→ π O Δ ++ at 13.1 GeV/ c incident momentum. For − t > 0.1 (GeV/ c ) 2 the data is well described by M1 ϱ-exchange models, the best results being obtained from a weak cut model with a wrong signature nonsense zero. For − t < 0.1 (GeV/c) 2 there is evidence for the existence of other exchange mechanisms.
No description provided.
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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.
No description provided.
A sample of approximately 250 Λp interactions has been obtained in the Λ-hyperon momentum range of about 300 to 500 MeV/ c . An enhanced Λ-hyperon production rate was obtained by exposing an internally-mounted platinum target to the incident 1.5 GeV/ c meson beam. Cross sections and angular distributions are obtained for the reactions: Λ p → Λ p, Λ p → Σ o p and Λ p → Λ p π o . In the elastic channel, no strong evidence is seen near the Σ o p threshold for the presence of a 3 S 1 resonance, which has been reported, although there is some evidence for a small enhancement in this mass region. There is evidence for the presence of P-waves and probably also D-waves above about 800 MeV/ c , but not below this momentum.
D(SIG)/DOMEGA IS ANALYSED IN TABLE 2 BY LEGENDRE POLYNOMIAL EXPANSION. ERRORS ADDED AS 1/SQRT(EVENTS).
D(SIG)/DOMEGA IS ANALYSED IN TABLE 2 BY LEGENDRE POLYNOMIAL EXPANSION. ERRORS ADDED AS 1/SQRT(EVENTS).
D(SIG)/DOMEGA IS ANALYSED IN TABLE 2 BY LEGENDRE POLYNOMIAL EXPANSION. ERRORS ADDED AS 1/SQRT(EVENTS).
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No description provided.
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 .
No description provided.
We measured the polarization parameter P in neutron-proton elastic scattering near the backward direction, using a polarized proton target. Measurements covered the range of incident neutron momenta from 1.0 to 5.5 GeV/ c and of four-momentum transfer squared u from −0.005 to −0.5 (GeV/ c ) 2 .
'1'. '2'. '3'. '4'.
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About 3700 two-prong and 5600 four-prong events of 10-GeV/c pp interactions in the Saclay 81-cm hydrogen bubble chamber have been measured and analyzed. The reliability of the identification of the different final states has been checked using Monte Carlo-generated events. For the channels accessible to analysis, cross sections and invariant-mass distributions are given. The c.m. angular distributions and the mean values of the transverse momentum for all final-state particles are shown and discussed. Production of Δ++(1236) accounts for about 30% of the cross section σ(pp→pnπ+)=4.1±0.4 mb. About 50% of the cross section σ(pp→ppπ+π−)=2.4±0.2 mb can be accounted for by Δ++ production. Production of nucleon isobars at 1450, 1520, and 1730 MeV and their subsequent decay into pπ+π− are investigated. Their cross sections, t dependences, and branching ratios are determined, using a one-pion-exchange model (OPEM) for calculating the background distributions. The production of resonances decaying into pπ− at 1236, 1500, and 1690 MeV is seen, and cross sections are given. Resonance production in the ppπ+π−π0 and pnπ+π+π− reactions is studied using background curves calculated with a model based on simple parametrizations of the c.m. momentum distributions. The production of nucleon isobars accounts for nearly 100% of these reactions. For the reactions pp→ppω, ppη, and ppf0, the cross sections found are 0.16±0.03, 0.16±0.07, and 0.10±0.04 mb, respectively, corrected for unobserved decay modes. It is shown that most of the gross features of the pion-production reactions can be explained by the OPEM with the form factors of Ferrari and Selleri.
No description provided.
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