Branching fraction of the isospin violating process phi to omega pi0

We examine the parametrization of the e+e- -> omega pi0 cross section in the vicinity of the phi resonance and the extraction of the branching fraction of the isospin violating process phi -> omega pi0 from experimental data. We found that there are two possible solutions of the branching fraction, one is 4 times 10^{-5}, and the other is 7 times 10^{-3}. The latter is two orders of magnitude higher than the former, which is the commonly accepted one

Review of experimental results from SND detector

The review of experimental results obtained with SND detector at VEPP-2M $e^+e^-$ collider in the energy region $\sqrt[]{s}=0.36$ -- 1.38 GeV is given. The presented results include the following items: studies of the light vector mesons radiative decays, OZI-rule and G-parity suppressed $\phi$-meson rare decays, $\phi$-meson parameters measurements, studies of $e^+e^-\to\pi^+\pi^-\pi^0$ process dynamics, $\eta$ and $K_S$ mesons rare decays, $\eta$ and $\phi$ mesons conversion decays, and study of the $e^+e^-$ annihilation into hadrons.Comment: 12 pages and 6 figures. Talk given at the IX International Conference on Hadron Spectroskopy, Protvino, Russia, August 25 - September 1, 200

Update of the e^+e^-\to\pi^+\pi^- cross section measured by SND detector in the energy region 400<\sqrt{s}<1000 MeV

The corrected cross section of the e^+e^-\to\pi^+\pi^- process measured in the SND experiment at the VEPP-2M e^+e^- collider is presented. The update is necessary due to a flaw in the e^+e^-\to\pi^+\pi^- and e^+e^-\to\mu^+\mu^- Monte Carlo events generators used previously in data analysis.Comment: 10 pages,7 figure

Study of the process e+e-\to \mu+\mu- in the energy region \sqrt{s}=980, 1040 -- 1380 MeV

The cross section of the process e+e-\to\mu+\mu- was measured in the SND experiment at the VEPP-2M e+e- collider in the energy region \sqrt{s}=980, 1040 -- 1380 MeV. The event numbers of the process e+e-\to\mu+\mu- were normalized to the integrated luminosity measured using e+e-\to e+e- and e+e-\to\gamma\gamma processes. The ratio of the measured cross section to the theoretically predicted value is 1.006\pm 0.007 \pm 0.016 and 1.005 \pm 0.007 \pm 0.018 in the first and second case respectively. Using results of the measurements, the electromagnetic running coupling constant \alpha in the energy region \sqrt{s}=1040 -- 1380 MeV was obtained = 134.1\pm 0.5 \pm 1.2 and this is in agreement with theoretical expectation.Comment: 29 pages, 23 figure

Study of Δ(1232)\Delta(1232) isobar electroproduction at VEPP-2M e+e−e^+e^- collider

Results from the Spherical Nonmagnetic Detector (SND) on $\Delta (1232)$ isobar electroproduction in the collisions of beam electrons (positrons) and residual gas nuclei in the VEPP-2M $e^+e^-$ collider are presented. On the basis of the obtained data the expected counting rate of this process in future high luminosity $e^+e^-$ colliders (~$\phi$-, $c$-$\tau$- and $b$-factories) was estimated.Comment: 7 pages LATEX and 3 figure

Study of the process e+e−→π+π−π0e^+e^- \to \pi^+\pi^-\pi^0 in the energy region s\sqrt[]{s} below 0.98 GeV

The cross section of the process $e^+e^-\to \pi^+\pi^-\pi^0$ was measured in the Spherical Neutral Detector (SND) experiment at the VEPP-2M collider in the energy region $\sqrt[]{s}$ below 980 MeV. This measurement was based on about $1.2 \times 10^6$ selected events. The obtained cross section was analyzed together with the SND and DM2 data in the energy region $\sqrt[]{s}$ up to 2 GeV. The $\omega$-meson parameters: $m_\omega=782.79\pm 0.08\pm 0.09$ MeV, $\Gamma_\omega=8.68\pm 0.04\pm 0.15$ MeV and $\sigma(\omega\to 3\pi)=1615\pm 9\pm 57$ nb were obtained. It was found that the experimental data cannot be described by a sum of only $\omega$, $\phi$, $\omega^\prime$ and $\omega^{\prime\prime}$ resonances contributions. This can be interpreted as a manifestation of $\rho\to 3\pi$ decay, suppressed by $G$-parity, with relative probability $B(\rho\to 3\pi) = (1.01\pm^{0.54}_{0.36}\pm 0.034) \times 10^{-4}$.Comment: 41 pages REVTEX and 34 figure