273 research outputs found

    Energy calibration of the NaI(Tl) calorimeter of the SND detector using cosmic muons

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    The general purpose spherical nonmagnetic detector (SND) is now taking data at VEPP-2M e+e−e^+e^- collider in BINP (Novosibirsk) in the centre of mass energy range of 0.2Ă·1.40.2 \div 1.4 GeV. The energy calibration of the NaI(Tl) calorimeter of the SND detector with cosmic muons is described. Using this method, the energy resolution of 5.55.5 % (\sigma) for 500 MeV photons was achieved.Comment: 15 pages, Latex, 11 figures (.EPS

    Energy calibration of the NaI(Tl) calorimeter of the SND detector using e+e−→e+e−e^+e^- \to e^+e^- events

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    Calibration of the three layer NaI(Tl) spherical calorimeter of the SND detector using electron -- positron scattering events is described. Energy resolution of 55 % (FWHM/2.36) for 500 MeV photons was achieved.Comment: 12 pages, Latex, 8 figures (.EPS

    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

    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

    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 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 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.

    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.
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