The ratio of π − to π + electroproduction cross sections from deuterons has been measured in the resonance region at an average four-momentum transfer squared of 0.5 (GeV/ c ) 2 . Results are presented over a wide range of pion production angles and comparisons are made with theoretical predictions based on SU(6) w symmetry and the Melosh transformation.
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We have performed in the NA3 experiment the study of high mass dimuon production by a hadronic unseparated beam on hydrogen and platinum targets. The comparison of the production cross‐section for proton and antiproton together with the differential cross‐section dσ/dx allows us to compare the data with a production mechanism involving quark‐antiquark and gluon‐gluon interactions. The cosΘ* distribution of the same J/ψ data have also been analysed and results will be presented. Finally we have observed T production from 150 GeV/c incident pions.
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p p annihilations, leading to the production of at least one neutral K meson in the final state, have been studied in the incident momentum region of 700–760 MeV/ c . Topological cross sections and cross sections for the various exclusive final states are presented. Detailed analyses of the different final states have been carried out to study the importance of resonance production and of quasi two-body and quasi three-body processes. A detailed study of the K K π system in the four-body final states shows that the F 1 meson is a spurious effect due to systematic biases. In the momentum range investigated, the C = +1 final states are strongly suppressed.
SUMMARY OF QUASI-TWO-BODY CROSS SECTIONS.
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Proton-proton elastic scattering using 201- and 400-GeV/c extracted beams at Fermilab has been measured in the region 4.9<−t<14.4 GeV2. Contrary to predictions of diffraction models, there is no sign of a second dip or "break," and the slope A in the fit exp(At) is smaller than predicted. It drops from 1.5 to 0.8 GeV−2 over our t range. The shape of the t distribution can be fitted by the power law dσdt∝t−8.4 which is close to a quantum-chromodynamics (QCD) prediction of t−8. At fixed t the 201-GeV/c cross sections are about 2.3 times those at 400 GeV/c which is compatible with the QCD and constituent-interchange-model prediction that dσdt∝s−10 at fixed ts.
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The polarization of the recoil proton has been measured in both high-energy elastic and inclusive proton-proton scattering at the internal-target area of Fermi National Accelerator Laboratory. The polarization in elastic scattering was measured at a number of center-of-mass energies up to s=19.7 GeV. Indications of negative polarization were seen at the higher center-of-mass energies for t values of -0.6, -0.8, and -1.0 (GeV/c)2. In the inclusive process p+p→p↑+X the polarization was found to be independent of beam energy from 100 to 400 GeV for xF values of -0.7, -0.8, -0.9. The polarization at PT=1.0 GeV/c, xF=−0.7 and xF=−0.8 was less than 2.5%. This is significantly lower than the corresponding measurements reported for Λ0 inclusive polarization.
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The resonance parameters of the ϒ′(10.01) were measured using the LENA detector at the DORIS e + e − storage ring. We obtained a mass of M ( ϒ ′) = (10 013.6 ± 1.2 ± 10.0) MeV and an electronic width of Γ ee ( ϒ ′) = (0.53 ± 0.07 −0.05 +0.09 keV. The upper limit set to the μ-pair branching ratio is 3.8% which implies a lower limit on the total ϒ′ width of 14 keV. Together with out previous measurement of the ϒ parameters we obtain a mass difference M(ϒ′) − M(ϒ) = (552.0 ± 1.3 ± 10.0) MeV and Γ ee (ϒ′) Γ ee (ϒ) = 0.43 ± 0.07 −0.00 +0.05 .
HADRONIC CROSS SECTION IN REGION OF UPSI(10020)0.
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The cross sections of several exclusive reactions in p p interactions are given. In the channels p p → p p π + π − and p p → p p 2π + 2π − which dominate the interactions, the single and double diffractive dissociations are analysed and compared to the results obtained with K ± p interactions at the same energy, pp and p p interactions at other energies. The test of factorization at the p → p π + π − vertex is well verified. The process p p → Δ ++ Δ ++ is studied and the cross sections of Δ ++ , Δ ++ , ϱ 0 and f 0 production are also given.
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