We have measured the production cross section for K s 0 in e + e − annihilation from 3.6 to 5.0 GeV center of mass energy. A substantial increase of the K s 0 yield is observed around 4 GeV in qualitative agreement with the charm hypothesis.
THE DATA GIVEN HERE AT 9.3 GEV AND ABOVE ARE REPORTED IN C. BERGER ET AL., PL 104B, 79 (1981). THE 12.0 AND 30 GEV DATA WERE TAKEN AT PETRA.
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This paper gives a detailed description of an experiment which studies the interactions of muon-type neutrinos in hydrogen and deuterium. The experiment was performed at the Zero Gradient Synchrotron using the wide-band neutrino beam incident on the Argonne 12-foot bubble chamber filled with hydrogen and deuterium. The neutrino energy spectrum peaks at 0.5 GeV and has a tail extending to 6 GeV. The shape and intensity of the flux is determined using measurements of pion yields from beryllium. The produced pions are focused by one or (for the latter part of the experiment) two magnetic horns. A total of 364000 pictures were taken with a hydrogen filling of the bubble chamber and 903 000 with a deuterium filling. The scanning and other analyses of the events are described. The most abundant reaction occurs off neutrons and is quasi-elastic scattering νd→μ−pps. The separation of these events from background channels is discussed. The total and differential cross sections are analyzed to obtain the axial-vector form factor of the nucleon. Our result, expressed in terms of a dipole form factor, gives an axial-vector mass of 0.95±0.09 GeV. A comparison is made to previous measurements using neutrino beams, and also to determinations based upon threshold pion electroproduction experiments. In addition, the data are used to measure the weak vector form factor and so check the conserved-vector-current hypothesis.
Measured Quasi-Elastic total cross section.
This paper gives the results of a study of inelastic charged-current interactions of muon-type neutrinos with hydrogen and deuterium targets using the Argonne 12-foot bubble chamber. We discuss in detail the separation of the events from background. For the single-pion production reactions νp→μ−pπ+, νn→μ−nπ+, and νn→μ−pπ0, energy-dependent cross sections, differential cross sections, invariant-mass distributions, and the Δ++(1236) decay angular distribution are presented. These data are also used to study the isospin properties of the πN system. Comparisons of the data with models of single-pion production are made, and a direct test of partial conservation of the axial-vector current is discussed. Cross sections and invariant-mass distributions are given for the reactions in which more than one pion is produced. Ten events of strange-particle production were found, and the properties of these events are discussed. The energy dependence of the total νp and νn cross sections from threshold to 6 GeV was determined, and the σ(νn)σ(νp) ratio measured. This ratio and the inclusive x and y distributions rapidly approach the scaling distributions expected from the quark-parton model.
Measured charged current total cross section.
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We present the first data on photon-photon annihilation into hadrons for CM energies > 1 GeV obtained with the detector PLUTO at the e + e − storage ring PETRA. Cross sections are extracted using an inelastic eγ scattering formalism. The results are compared to expectations from Regge-like models.
DEPENDENCE OF CROSS SECTION FOR ELECTRON-PHOTON SCATTERING (ANALOGOUS TO HAND'S FORMULA) ON VISIBLE HADRONIC ENERGY, CALCULATED BY TAKING PION MASSES FOR ALL CHARGED PARTICLES.
We present a measurement of the cross section for hadron production by e+e− annihilation in the vicinity of the previously observed resonance near 3.77 GeV. The data are used to determine the parameters of the ψ(3770) resonance. The values found are: mass, 3764±5 MeV/c2, total width, 23.5±5 MeV, and partial width to electron pairs, 276±50 eV.
THESE RESULTS ARE ALSO IN THE THESIS OF R. H. SCHINDLER, SLAC-219 (1979), THE RECORD OF WHICH CONTAINS THE TABULATED CROSS SECTIONS.
BREIT-WIGNER RESONANCE PLUS BACKGROUND FIT TO RADIATIVELY CORRECTED DATA YIELDS RESONANCE MASS OF 3764 +- 5 MEV, TOTAL WIDTH OF 23.5 +- 5 MEV AND PARTIAL WIDTH TO ELECTRON PAIRS OF 276 +- 50 EV.
PEAK CROSS SECTION FOR D MESON PAIR PRODUCTION AT PSI(3770) RESONANCE. J/PSI, PSI(3684) AND CONTINUUM BACKGROUND (R=2.5) SUBTRACTED.
We have identified 262 doubly tagged two-photon events. A subset of the data shows an enhancement of 21 events in the inclusive two-photon mass squared distribution between 0.8 and 2.2 GeV 2 . If these events result from spin 2 resonance production then Γ γγ = 9.5 ± 3.9 ± 2.4 keV (statistical and systematic). From another subset of 58 events in which the final state could be classified we determine the two-photon hadron to muon cross section ratio R γγ = 1.1 ± 0.3 ± 0.3.
ELECTRON BEAM ENERGIES OF 3.0 AND 3.6 GEV.
To complete data on resonance electroproduction we constructed an electron spectrometer with large angular and momentum acceptance. As a first result inclusive cross sections for an invariant hadronic mass 1.2<W<1.7 GeV and a four momentum transfer squared 0.5<Q2<1.5 (GeV/c)2 and for values of the polarization parameter 0.1<ɛ<0.25 are presented. Combining our results with the SLAC 4°-data we obtain σL/σT in the specified kinematical range.
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We present new high statistics data on hadron production in photon-photon reactions. The data are analyzed in terms of an electron-photon scattering formalism. The dependence of the total cross section of Q 2 , the four-momentum transfer squared of the scattered electron, and on the mass W of the hadronic system is investigated. The data are compared to predictions from Vector-Meson Dominance and the quark model.
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DEPENDENCE ON VISIBLE HADRONIC INVARIANT MASS.
Data read from graph.
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