19 research outputs found

    The process e+e−→π+π−π0e^+e^-\to\pi^+\pi^-\pi^0 in the energy range 2E_0=1.04 - 1.38 GeV

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    In the experiment with the SND detector at VEPP-2M e^+e^- collider the process e+e−→π+π−π0e^+e^-\to\pi^+\pi^-\pi^0 was studied in the energy range 2E_0 from 1.04 to 1.38 GeV. A broad peak was observed with the visible mass Mvis=1220±20M_{vis}=1220\pm 20 MeV and cross section in the maximum σ0≃4\sigma_0\simeq 4 nb. The peak can be interpreted as a ω\omega-like resonance ω(1200)\omega (1200).Comment: 10 pages LATEX and 5 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.

    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.

    New experimental data for the decays ϕ→Ό+Ό−\phi\to\mu^+\mu^- and ϕ→π+π−\phi\to\pi^+\pi^- from SND detector

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    The processes e+e−→Ό+Ό−e^+e^-\to\mu^+\mu^- and e+e−→π+π−e^+e^-\to\pi^+\pi^- have been studied with SND detector at VEPP-2M e+e−e^+e^- collider in the vicinity of ϕ(1020)\phi(1020) resonance. The branching ratios B(ϕ→Ό+Ό−)=(3.30±0.45±0.32)×10−4B(\phi\to\mu^+\mu^-)=(3.30\pm 0.45\pm 0.32)\times 10^{-4} and B(ϕ→π+π−)=(0.71±0.11±0.09)×10−4B(\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

    Radiative decays of light vector mesons

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    The new data on ρ,ω,ϕ\rho,\omega,\phi radiative decays into π0Îł,ηγ,ηâ€ČÎł\pi^0\gamma,\eta\gamma,\eta'\gamma from SND experiment at VEPP-2M e+e−e^+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

    Search for the radiative decay η→π0γγ\eta \to \pi^0 \gamma \gamma in the SND experiment at VEPP-2M

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    The η→π0γγ\eta \to \pi^0 \gamma \gamma decay was investigated by the SND detector at VEPP-2M e+e−e^+e^- collider in the reaction e+eâˆ’â†’Ï•â†’Î·Îłe^+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(η→π0γγ)<8.4×10−4Br(\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.

    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

    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

    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

    First Observation of PHI(1020)--->PI0+PI0+GAMMA Decay

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    In the SND experiment at the VEPP-2M electron-positron collider the PHI(1020)--->PI0+PI0+GAMMA decay was studied. The branching ratio B(PHI--->PI0+PI0+GAMMA)=(1.14+-0.10+-0.12)x10^{-4} was measured. It was shown, that the F0(980)GAMMA mechanism dominates in this decay and the 4-quark model of F0(980) describes our data most consistently.Comment: 6 pages, 6 figures, 1 table, Will be published in Phys.Lett.
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