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تسجيل مستخدم جديدMeasurement of $phi$(1020) meson leptonic width with CMD-2 detector at VEPP-2M Collider
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The $phi$(1020) meson leptonic width has been determined from the combined analysis of 4 major decay modes of the resonance ($phito K^+ K^-,K^0_LK^0_S,pi^+pi^-pi^0,etagamma$) studied with the CMD-2 detector at the VEPP-2M $e^+e^-$ collider. The following value has been obtained: $Gamma(phito e^+e^-) = 1.235pm 0.006pm 0.022$ keV. The $phi(1020)$ meson parameters in four main decay channels have been also recalculated: $B(phito K^+K^-) = 0.493pm 0.003pm 0.007$, $B(phito K_LK_S) = 0.336pm 0.002pm 0.006$, $B(phitopi^+pi^-pi^0) = 0.155pm 0.002pm 0.005$, $B(phitoetagamma) = 0.0138pm 0.0002pm 0.0002$.
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The process e+ e- -> phi -> K+ K- has been studied with the CMD-2 detector using about 542 000 events detected in the center-of-mass energy range from 1.01 to 1.034 GeV. The systematic error of the cross section is estimated to be 2.2%. The phi(1020)
meson parameters in the phi -> K+K- decay channel have been measured: sigma_0(phi-> K+K-) = 2016 +- 8 +- 44 nb, m(phi) = 1019.441 +- 0.008 +- 0.080 MeV/c2, Gamma(phi) = 4.24 +- 0.02 +- 0.03 MeV, B(e+e-)B(K+K-) = (14.27 +- 0.05 +- 0.31)*10(-5).
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Short overview of experiments with SND detector at VEPP-2M e^+e^- collider in the energy range 2E = 400 - 1400 MeV and preliminary results of data analysis are presented.
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10^{-4} agrees well with the PDG value B(phi->e+e-)=(2.91+-0.07)*10^{-4} confirming mu-e universality. Without additional assumption of mu-e universality the branching ratio B(phi->mu+mu-)=(2.87+-0.20+-0.14)*10^{-4} was obtained.
The cross section of the process $e^{+}e^{-}rightarrowetapi^{+}pi^{-}$ is measured using the data collected with the CMD-$3$ detector at the VEPP-$2000$ collider in the center-of-mass energy range from $1.1$ to $2.0$ GeV. The decay mode $etarightarro
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