This paper presents the results of a study of the dominant neutral final states from π−p interactions. The data were obtained in an experiment performed at the Brookhaven National Laboratory Alternating Gradient Synchrotron, using a set of steel-plate optical spark chambers surrounding a liquid-hydrogen target. We present differential and total cross sections for the reactions (1) π−p→n+π0 and (2) π−p→n+η0(η0→2γ) and total cross sections for the reactions (3) π−p→n+kπ0 (k=2, 3, 4, and 5) and (4) π−p→all neutrals for eighteen values of beam momentum in the interval 1.3 to 4.0 GeV/c. The angular distributions for (1) and (2) have been analyzed in terms of expansions in Legendre polynomials, the coefficients for which are also given.
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SIG = 4*PI*LEG(L=0).
FORWARD DIFFERENTIAL CROSS SECTION CALCULATED FROM LEGENDRE POLYNOMIAL COEFFICIENTS AND ERROR MATRICES.
Data from the MARK-J detector on the reactions e+e−→μ+μ−, τ+τ− in the center-of-mass energy range from 12 to 36.7 GeV are presented. The μ, τ radii are shown to be <10−16 cm. A search has been made for the production of a new heavy lepton and for the production of spin-0 supersymmetric partners of the muon. 95%-confidence-level lower limits of 16 GeV for the mass of a new charged heavy lepton and 15 GeV for the mass of the scalar partners of the muon are obtained.
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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.
αα elastic scattering was measured at 4.32 GeV/ c and 5.07 GeV/ c incident momenta. The four-momentum transfer range, extending from −0.05 to −0.77 (GeV/ c ) 2 , covers the first and second minimum regions. The results are compared with calculations based on Glauber theory.
ERRORS SHOWN INCLUDE STATISTICAL ERRORS, QUASIELASTIC CONTRIBUTION SUBTRACTION ERROR, AND AN ASSYMETRIC ERROR RESULTING FROM THE UNCERTAINTIES AS TO THE ORIGIN OF THE WIDENING OF THE ELASTIC PEAK.
ERRORS SHOWN INCLUDE STATISTICAL ERRORS, QUASIELASTIC CONTRIBUTION SUBTRACTION ERROR, AND AN ASSYMETRIC ERROR RESULTING FROM THE UNCERTAINTIES AS TO THE ORIGIN OF THE WIDENING OF THE ELASTIC PEAK.
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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DIFFRACTION DISSOCIATION EVENTS.
NON-DIFFRACTION EVENTS.
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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Topological distributions of charged and neutral hadrons from the reaction e + e − → multihadrons are studied at √ s of about 30 GeV. An excess of planar events is observed at a rate which cannot be explained by statistical fluctuations in the standard two-jet process. The planar events, mostly consisting of a slim jet on one side and a broader jet on the other, are shown actually to possess three-jet structure by demonstrating that the broader jet itself consists of two collinear jets in its own rest system. Detailed agreement between data and predictions is obtained if the process e + e − →q q ̄ g is taken into account. This strongly suggests gluon bremsstrahlung as the origin of the planar three-jet events. By comparison of the data with the qq̄g-model we obtain a value for the strong coupling constant of α S ( q 2 = 0.17 ± 0.04.
THRUST AND PLANARITY DISTRIBUTIONS. FINAL (BETTER) THRUST DISTRIBUTIONS WITH DETECTOR CORRECTIONS TO BE PUBLISHED LATER.
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We have measured π+p, π−p, and pp elastic scattering at an incident-beam momentum of 200 GeV/c in the region of −t, four-momentum transfer squared, from 0.021 to 0.665 (GeV/c)2. The data allow an investigation of the t dependence of the logarithmic forward slope parameter b≡(ddt)(lndσdt). In addition to standard parametrization, we use functional forms suggested by the additive quark model to fit the measured dσdt distributions. Within the context of this model we estimate the size of the clothed quark in the pion and proton. Limits on the elastic-scattering amplitude derived from unitarity bounds are checked, and no violations are observed.
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DATA FOR EVNENT WITHOUT PAIRS FROM INTERFIERENCE REGION - YF 27, 1556.
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