23 research outputs found

    Radiative decays of light vector mesons

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    The new data on ρ,ω,ϕ\rho,\omega,\phi radiative decays into π0γ,ηγ,ηγ\pi^0\gamma,\eta\gamma,\eta'\gamma from SND experiment at VEPP-2M e+ee^+e^- collider are presented.Comment: 5 pages, 2 figures, talk given at 8th International Conference on Hadron Spectroscopy (HADRON 99), Beijing, China, 24-28 Aug 199

    New experimental data for the decays ϕμ+μ\phi\to\mu^+\mu^- and ϕπ+π\phi\to\pi^+\pi^- from SND detector

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    The processes e+eμ+μe^+e^-\to\mu^+\mu^- and e+eπ+πe^+e^-\to\pi^+\pi^- have been studied with SND detector at VEPP-2M e+ee^+e^- collider in the vicinity of ϕ(1020)\phi(1020) resonance. The branching ratios B(ϕμ+μ)=(3.30±0.45±0.32)×104B(\phi\to\mu^+\mu^-)=(3.30\pm 0.45\pm 0.32)\times 10^{-4} and B(ϕπ+π)=(0.71±0.11±0.09)×104B(\phi\to\pi^+\pi^-)=(0.71\pm 0.11\pm 0.09)\times 10^{-4} were obtained.Comment: 5 pages, 4 figures, talk given at 8th International Conference on Hadron Spectroscopy (HADRON 99), Beijing, China, 24-28 Aug 199

    Search for direct production of a2(1320) and f2(1270) mesons in e+e- annihilation

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    A search for direct production of C-even resonances a2(1320) and f2(1270) in e+e- annihilation was performed with SND detector at VEPP-2M e+e- collider. The upper limits of electronic widths of these mesons were obtained at 90% confidence level: Gamma(a2(1320) \to e+e-) < 0.56 eV, Gamma(f2(1270) \to e+e-) < 0.11 eV.Comment: 6 pages, 5 figures, 1 table. Submitted to Phys. Lett.

    Registration of atmospheric neutrinos with the Baikal neutrino telescope

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    We present first neutrino induced events observed with a deep underwater neutrino telescope. Data from 70 days effective life time of the BAIKAL prototype telescope NT-96 have been analyzed with two different methods. With the standard track reconstruction method, 9 clear upward muon candidates have been identified, in good agreement with 8.7 events expected from Monte Carlo calculations for atmospheric neutrinos. The second analysis is tailored to muons coming from close to the opposite zenith. It yields 4 events, compared to 3.5 from Monte Carlo expectations. From this we derive a 90 % upper flux limit of 1.1 * 10^-13 cm^-2 sec^-1 for muons in excess of those expected from atmospheric neutrinos with zenith angle > 150 degrees and energy > 10GeV.Comment: 20 pages, 11 figure

    Experimental Study of rho -> pi0 pi0 gamma and omega -> pi0 pi0 gamma Decays

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    The e+e- -> pi0 pi0 gamma process was studied in the SND experiment at VEPP-2M e+e- collider in the energy region 0.60-0.97 GeV. From the analysis of the energy dependence of measured cross section the branching ratios B(omega -> pi0 pi0 gamma)= (6.6 +1.4-0.8(stat) +-0.6(syst))x10^-5 and B(rho -> pi0 pi0 gamma)=(4.1 +1.0-0.9(stat) +-0.3(syst))x10^-5 were obtained.Comment: 16 pages, 7 figures, submitted to Phys. Lett.

    Experimental study of the e+e- -> pi0 gamma process in the energy region sqrt(s)=0.60-0.97 GeV

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    Results of the study of the e+e-->pi0 gamma process with SND detector at VEPP-2M collider in the c.m.s. energy range sqrt(s)=0.60-0.97 GeV are presented. Using 36513 selected events corresponding to a total integrated luminosity of 3.4 pb^-1 the e+e-->pi0 gamma cross section was measured. The energy dependence of the cross section was analyzed in the framework of the vector meson dominance model. The data are well described by a sum of phi,omega,rho0->pi0 gamma decay contributions with measured decay probabilities: Br(omega->pi0 gamma)=(9.34+-0.15+-0.31)% and Br(rho0->pi0 gamma)=(5.15+-1.16+-0.73)*10^-4 . The rho-omega relative interference phase is phi(rho,omega}=(-10.2+-6.5+-2.5) degree

    New Data from SND Detector in Novosibirsk

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    The current status of experiments with SND detector at VEPP-2M e^+e^- collider in the energy range 2E_0=400-1400 MeV and recent results of data analysis for ϕ\phi, ω\omega and ρ\rho decays and e^+e^- annihilation into hadrons are presented.Comment: 7 pages, 8 figures, Latex2e, uses espcrc1.sty. Talk given at 8th International Conference on Hadron Spectroscopy (HADRON 99), Beijing, China, 24-28 Aug 199

    Pion Form Factor at SND (new edition)

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    The update of the e^+e^-\to\pi^+\pi^- process cross section, measured in the energy region \sqrt{s}<1 GeV with SND detector at VEPP-2M collider is presented.Comment: Talk given at Int. Workshop e+e- Collisions from phi to psi, February 27 - March 2, 200

    Search for the radiative decay ηπ0γγ\eta \to \pi^0 \gamma \gamma in the SND experiment at VEPP-2M

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    The ηπ0γγ\eta \to \pi^0 \gamma \gamma decay was investigated by the SND detector at VEPP-2M e+ee^+e^- collider in the reaction e+eϕηγe^+e^-\to\phi\to \eta\gamma. Here we present the results and some details of this study. We report an upper limit (90% c.l.) Br(ηπ0γγ)<8.4×104Br(\eta \to \pi^0 \gamma \gamma)<8.4\times 10^{-4} as our final result. Our upper limit does not contradict the earlier measurement by GAMS spectrometer. To facilitate future studies a rather detailed review of the problem is also given.Comment: 24 pages, 6 figures, LaTex. To be published in Nucl. Phys.
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