Differential cross sections and polarization analyzing powers for proton-deuteron elastic scattering have been measured at 800 MeV incident proton kinetic energy over the range of center-of-mass angles from 14.1° to 153.6°. The differential cross sections are described by the Glauber theory of impulse approximation at forward angles (−t<0.5) and exhibit the exponential dependence on cosθc.m. typical for these energies at backward angles (cosθc.m.<−0.5). The analyzing power shows considerable structure with strong positive peaks at forward and backward angles and a sharp dip at t=−0.4 typical at intermediate energies. There is no evidence for correspondence of the angular dependence of the analyzing power with that for the pp→dπ+ reaction. At large momentum transfer the data favor calculations based on multiple scattering with a modified deuteron form factor rather than N* exchange. NUCLEAR REACTIONS H2(p,p)H2, E=800 MeV, measured σ(θ) and Ay(θ).
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We have measured direct photon production in pp collisions at the CERN intersecting storage rings for c.m. energies 31 < √ s < 63 GeV and transverse momenta up to 9GeV/ c , using segmented lead/liquid-argon calorimeters. The ratio of direct photon to π 0 production is significantly larger than zero, starting at p T ≈ 4 GeV/ c and increasing to values of about 0.4 at 9GeV/ c . No significant √s dependence is seen.
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DOMINANT NATURAL PARITY EXCHANGE.
EVIDENCE FOR FORWARD DIP FOR -TP < 0.1 GEV**2.
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We have measured the spin-correlation parameters A00kk, A00ks, and A00ss in p−p scattering between 400 and 600 MeV using a longitudinally polarized beam and a butanol target polarized in the horizontal plane. Owing to the restrictive geometrical acceptance of the target, the polarization axis of the target was oriented at an angle α with respect to beam direction. The parameters A00kk and A00ks were therefore measured as a linear combination at 577, 536, 514, 494, and 445 MeV. These experiments were extended to the measurement of A00ks and A00ss by using a transversely polarized beam. We present the results, which are compared with phase-shift predictions.
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The ϒ, ϒ′, and ϒ′′ states have been observed at the Cornell Electron Storage Ring as narrow peaks in σ(e+e−→hadrons) versus beam energy. Data were collected during a run with integrated luminosity of 1000 nb−1, using the Columbia University-Stony Brook segmented NaI detector. The measured mass differences are M(ϒ′)−M(ϒ)=559±1(±3) MeV and M(ϒ′′)−M(ϒ)=889±1(±5) MeV, where the errors in parentheses represent systematic uncertainties. Preliminary values for the leptonic width ratios were also obtained.
HADRONIC EVENTS/SMALL-ANGLE BHABHA YIELD.
Relative cross sections have been measured for p¯p annihilation by a new technique in the invariant-mass range 1920-1960 MeV. The 90%-confidence upper limit on simple Breit-Wigner enhancements in the S region (between 1930 and 1942 MeV) of width 4 MeV or narrower is 12 mb MeV, assuming a simple dependence with momentum of the nonresonant cross section.
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Results are presented from a study of inclusive neutral strange particle production by a 147 GeV/ c tagged π + /K + /p beam in the Fermilab 30-inch hydrogen bubble chamber. The experiment made use of the proportional hybrid spectrometer system. Results are based on 995 K S 0 , 485 Λ, and 83 Λ found in a sample of 132 000 pictures. Cross sections are given for inclusive production of these particles by each of the three beam particles, and comparisons are made with measurements at other energies. Topological cross sections are also calculated, and KNO multiplicity scaling is investigated. Distributions are presented of invariant cross sections as functions of the Feynman scaling variable x and c.m. rapidity y . The transverse momentum-squared distributions with their fitted slopes are also given. Comparisons are made of the production characteristics for the three beam types.
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We present measurements of two-particle angular correlations in hadron jets produced in e + e − annihilation between 7.7 and 31.6 GeV c.m. energy. The data are compared to predictions of high order perturbative QCD calculations.
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