83 research outputs found

    Aspects of a0-f0 mixing in the reaction pn->da0

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    Some aspects of a0-f0 mixing effects in the reaction pnda00{\vec p} n\to da^0_0 with perpendicular polarized proton beam are discussed. An angular--asymmetry parameter AA is defined to study those effects. It is shown that, for energies close to the production threshold, the angular--asymmetry parameter A(θ,ϕ)A(\theta, \phi) is proportional to the a0-f0 mixing amplitude for arbitrary polar and azimuthal angles θ\theta and ϕ\phi of the outgoing a0a_0 meson. This statement is also valid for arbitrary energies, but then only at polar angles θ=00\theta=0^0 and θ=900\theta=90^0. The mass dependence of the differential cross section dσ/dmπ0ηd\sigma/dm_{\pi^0\eta} in the reaction pndπ0ηpn\to d\pi^0\eta in the presence of \mix mixing is also discussed.Comment: 17 pages, 3 Figure

    Measurement of Inverse Pion Photoproduction at Energies Spanning the N(1440) Resonance

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    Differential cross sections for the process pi^- p -> gamma n have been measured at Brookhaven National Laboratory's Alternating Gradient Synchrotron with the Crystal Ball multiphoton spectrometer. Measurements were made at 18 pion momenta from 238 to 748 MeV/c, corresponding to E_gamma for the inverse reaction from 285 to 769 MeV. The data have been used to evaluate the gamma n multipoles in the vicinity of the N(1440) resonance. We compare our data and multipoles to previous determinations. A new three-parameter SAID fit yields 36 +/- 7 (GeV)^-1/2 X 10^-3 for the A^n_1/2 amplitude of the P_11.Comment: 14 pages, 8 figures, submitted to PR

    The nucleon-nucleon interaction

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    We review the major progress of the past decade concerning our understanding of the nucleon-nucleon interaction. The focus is on the low-energy region (below pion production threshold), but a brief outlook towards higher energies is also given. The items discussed include charge-dependence, the precise value of the πNN\pi NN coupling constant, phase shift analysis and high-precision NN data and potentials. We also address the issue of a proper theory of nuclear forces. Finally, we summarize the essential open questions that future research should be devoted to.Comment: 42 pages, 12 figures, iopart.cls style; Topical Review prepared for J. Phys. G: Nucl. Part. Phy

    Search for the lepton-family-number nonconserving decay \mu -> e + \gamma

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    The MEGA experiment, which searched for the muon- and electron-number violating decay \mu -> e + \gamma, is described. The spectrometer system, the calibrations, the data taking procedures, the data analysis, and the sensitivity of the experiment are discussed. The most stringent upper limit on the branching ratio of \mu -> e + \gamma) < 1.2 x 10^{-11} was obtained

    Measurement of the η3π0\eta\to 3\pi^{0} slope parameter α\alpha with the KLOE detector

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    We present a measurement of the slope parameter α\alpha for the η3π0\eta\to 3\pi^{0} decay, with the KLOE experiment at the DAΦ\PhiNE ϕ\phi-factory, based on a background free sample of \sim 17 millions η\eta mesons produced in ϕ\phi radiative decays. By fitting the event density in the Dalitz plot we determine \alpha = -0.0301 \pm 0.0035\,stat\;_{-0.0035}^{+0.0022}\,syst\,. The result is in agreement with recent measurements from hadro- and photo-production experiments.Comment: 14 pages, 11 figure
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