A search for phi radiative decays has been performed using a data sample of about 2.0 million phi decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. From the selected e+ e- -> pi+ pi- gamma events the following results were obtained: B(phi -> f0(980) gamma) < 1x10-4 for destructive and B(phi -> f0(980) gamma) < 7x10-4 for constructive interference with the Bremsstrahlung process respectively, B(phi -> gamma -> pi+ pi- gamma) < 3x10-5 for E of gamma > 20 MeV, B(phi -> rho gamma) < 7x10-4. From the selected e+ e- -> mu+ mu- gamma events B(phi -> mu+ mu- gamma) = (2.3+-1.0)x10-5 has been obtained for E of gamma> 20 MeV. The upper limit on the P,CP-violating decay eta -> pi+ pi- has also been placed: B(eta -> pi+ pi-) < 9x10-4 . All upper limits are at 90 % C.L.
Only statistical errors are shown in the table.
The paper describes experiments with the SND detector at VEPP-2M collider, carried out during the period from October 1995 until June 1997. The total integrated luminosity of 6.4 pb^{-1} was collected in the energy range 2E=0.4-1.4 GeV (MHAD97 experiment), corresponding to 4*10^5 mu^+ mu^- pairs produced. Preliminary results of the 1996 phi-meson experiment (FI96) are presented. The total number of phi-mesons produced is 4*10^6. New data on rare decays of phi and eta (550) mesons, in particular B(phi -> eta gamma) = (1.30+-0.06+-0.07)%, B(phi -> pi^0 pi^0 gamma) = (1.1+-0.2)*10^{-4}, (M_{pi^0 pi^0} > 800 MeV), B(phi -> f^0 gamma) = (4.7+-1.0)*10^{-4}, B(phi -> eta pi^0 gamma) = (1.3+-0.5)*10^{-4}, B(phi -> eta' gamma) < 1.7*10^{-4}, B(phi -> 2 pi^0 ) < 6*10^{-4} were obtained.
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The results of a measurement of the ratio R = Y(phi pi+ pi-) / Y(omega pi+ pi-) for antiproton annihilation at rest in a gaseous and in a liquid hydrogen target are presented. It was found that the value of this ratio increases with the decreasing of the dipion mass, which demonstrates the difference in the phi and omega production mechanisms. An indication on the momentum transfer dependence of the apparent OZI rule violation for phi production from the 3S1 initial state was found.
(C=CORRECTED) the ratio with phase space correctio. The annihilation in liquid hydrogen (C=LIQUID) and in hydrogen at 3 atm (C=P).
Results of the measurement of the φ meson parameters with the general purpose detector CMD-2 at the upgraded e + e − collider VEPP-2M at Novosibirsk are presented. This is the first measurement of the four major φ decay modes in a single e + e − experiment. The results based on about 55,600 identified hadronic events are consistent with previous measurements, and have precision comparable to the current world average.
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The ITEP-PNPI collaboration presents the first results of the spin rotation parameter A + measurements in the second resonance region. The experiment was performed at the ITEP accelerator at a positive pion beam momentum 1.43 GeV/c for scattering angles θ cm = 127° and 133°. The setup was based on a polarized proton target and a carbon-plate polarimeter. The obtained data is compared with the predictions of the existing partial-wave analyses.
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The yields and average transverse momenta of pions, kaons, and antiprotons produced at the Fermilab p¯p collider at s=300, 540, 1000, and 1800 GeV are presented and compared with data from the energies reached at the CERN collider. We also present data on the dependence of average transverse momentum 〈pt〉 and particle ratios as a function of charged particle density dNcdη; data for particle densities as high as six times the average value, corresponding to a Bjorken energy density 6 GeV/fm3, are reported. These data are relevant to the search for quark-gluon phase of QCD.
PT RANGE FROM 0 TO INFINITY.
PT RANGE FROM 0 TO INFINITY.
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The complete results of the experiments carried out with the Neutral Detector at the e + e − storage ring VEPP-2M in the energy range 2 E =0.5–1.4 GeV are reviewed. The data sample corresponds to a total integrated luminosity of 19 pb −1 .
ND results from Dolinsky et al., PL B174 (1986) 453.. Statistical errors only are shown. There is an additional systematic errorof 8%.
New ND data.. Statistical errors only are shown. There is an additional systematic errorof 8%.
Averaged ND data.. Statistical errors only are shown. There is an additional systematic errorof 8%.
Results of systematic measurements of the asymmetry parameter in the elastic scattering of pions on polarized protons at 1.4–2.1 GeV/ c in the backward hemisphere are presented together with a test of the isospin invariance of the data set available on pion-proton scattering in the investigated momentum range. The transversity isodoublet amplitudes at 1.98 and 2.07 GeV/ c are reconstructed. The obtained data, the isospin analysis and amplitude reconstruction results are compared with the current phase-shift analysis predictions.
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NAME=THEORY DENOTES THE MONTE-CARLO GENERATED CROSS SECTIONS.
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