Using the colliding beam machine, VEPP-2, the excitation curve of the ø-meson resonance was investigated in the three main decay modes. The resonance parameters obtained are the width, the total cross-section and the branching ratios. Namely: Γ = (4.67 ± 0.42) Mev B ( K + K − ) = (54.0 ± 3,4) % σ o = (3.96 ± 0.35) μB B ( K o s K O L ) = (25.7 ±3,0) % B ( e + e − = (2,81 ± 0.25) × 10 −4 B ( π + π − π o ) = (20.3 ± 4,2) %
BREIT-WIGNER FITS TO DATA POINTS AT 9 ENERGIES AROUND PHI FOR EACH CHANNEL. PEAK CROSS SECTIONS QUOTED.
PION FORM FACTOR AT PHI MASS, ALLOWING FOR POSSIBLE INTERFERENCE.
The cross section of the reaction e + e − → π + π − has been measured in the energy range 2 E from 0.78 up to 1.34 GeV. The obtained experimental values of the pion form factor exceed notably the ρ -meson tail.
No description provided.
The cross section of the reaction e + e − → K + K − has been measured at the electron-positron storage ring VEPP-2M in the c.m. energy range 1.0–1.4 GeV. At energies above 1.15 GeV the experimental values of the charged kaon form factor considerably exceed the predictions of the simplest vector dominance model with ϱ, ω, ψ mesons.
No description provided.
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Axis error includes +- 0.0/0.0 contribution (?////NOT GIVEN).
The pion electromagnetic form factor has been measured at the VEPP-2M collider in the c.m. energy range 360 MeV–1400 MeV with the detectors OLYA and CMD. On the basis of all available data for the pion form factor collected in the timelike region, the following values for ρ-meson parameters were obtained: m ρ = 775.9 ± 1.1 MeV, σ ρ = 150.5 ± 3.0 MeV. The ω-meson branching ratio into π + π − pair, electromagnetic radius of the pion, ππ scattering length in the P-wave and the strong interaction contribution to the muon ( g − 2) value were found to be B ωππ = (2.3 ± 0.4)%, 〈 r π 2 〉 = 0.422 ± 0.013 fm 2 , a 1 1 = 0.033 ± 0.033m π −3 , a H = (68.4 ± 1.1) × 10 −9 .
No description provided.
Experimental data from the OLYA detector
No description provided.
A study of the φ → π + π − π 0 decay mode has been performed using a data sample of about 2.0 million φ decays collected by the CMD-2 detector at VEPP-2M collider in Novosibirsk. The following parameters of the φ -meson have been measured: Br ( φ → π + π − π 0 )=0.145±0.009±0.003 and δ φ − ω =162±17°. The analysis of the Dalitz plot showed the dominance of the φ → ρπ intermediate mechanism, the limits for the ratio of the direct amplitude of φ →3 π to that of φ → ρπ are −0.16< a 1 <0.11 at 90% C.L. The upper limits for the probabilities of the decay modes φ → π + π − η and direct φ → ργγ have been found for the first time: Br ( φ → π + π − η )<3×10 −4 and Br ( φ → ργγ )<5×10 −4 at 90% C.L.
No description provided.
First results of the study of the process e+e- \to 4\pi by the CMD-2 collaboration at VEPP-2M are presented for the energy range 1.05--1.38 GeV. Using an integrated luminosity of 5.8 pb^{-1}, energy dependence of the processes e+e- \to \pi^+\pi^- 2\pi^0 and e+e- \to 2\pi^+ 2\pi^- has been measured. Analysis of the differential distributions demonstrates the dominance of the a_1\pi and \omega\pi intermediate states. Upper limits for the contributions of other alternative mechanisms are also placed.
Energy dependence of the cross section for the 2PI+ 2PI- final state. Statistical errors only.
Energy dependence of the cross section for the PI+ PI- 2PI0 final state. Statistical errors only.
Energy dependence of the cross section for the OMEGA PI0 final state. Statistical errors only.
About 300 000 $e^+e^-\to \phi\to K^0_L K^0_S$ events in the center of mass energy range from 984 to 1040 MeV were used for the measurement of the $\phi$ meson parameters. The following results have been obtained: $\sigma_0 = (1367 \pm 15 \pm 21) nb, m_{\phi}=(1019.504 \pm 0.011 \pm 0.033) MeV/c^2, \Gamma_\phi=(4.477 \pm 0.036 \pm 0.022) MeV, \Gamma_{e^+e^-}\cdot B(\phi\to K^0_L K^0_S) = (4.364 \pm 0.048 \pm 0.065)\cdot 10^{-4}$ MeV.
Updated measurements of the E+ E- --> PHI --> K0L K0S measured and 'bare' cross sections for SCAN 1.
Updated measurements of the E+ E- --> PHI --> K0L K0S measured and 'bare' cross sections for SCAN 2.
Updated measurements of the E+ E- --> PHI --> K0L K0S measured and 'bare' cross sections for SCAN 3.
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