The vector and tensor polarizations of a deuteron beam have been measured using elastic deuteron-carbon scattering at 75.6 MeV and deuteron-proton scattering at 270 MeV. After their acceleration to 1170 MeV inside the COSY ring, the polarizations of the deuterons were checked by studying a variety of nuclear reactions using a cluster target at the ANKE magnet spectrometer placed at an internal target position of the storage ring. All these measurements were consistent with the absence of depolarization during acceleration and provide us with a number of secondary standards that can be used in subsequent experiments at the facility
The product of the electronic width of the J/ψ meson and the branching fractions of its decay to hadrons and electrons has been measured using the KEDR detector at the VEPP-4M e + e − collider. The obtained values are Γ ee (J/ψ) = 5.550 ± 0.056 ± 0.089 keV, Γ ee (J/ψ) · B hadrons (J/ψ) = 4.884 ± 0.048 ± 0.078 keV, Γ ee (J/ψ) · B ee (J/ψ) = 0.3331 ± 0.0066 ± 0.0040 keV.The uncertainties shown are statistical and systematic, respectively. Using the result presented and the world-average value of the electronic branching fraction, one obtains the total width of the J/ψ meson: Γ = 92.94 ± 1.83 keV.These results are consistent with the previous experiments.
Measurement of J /ψ → γ η c decay rate and η c parameters at KEDR Using the inclusive photon spectrum based on a data sample collected at the J /ψ peak with the KEDR detector at the VEPP-4M e + e − collider, we measured the rate of the radiative decay J /ψ → γ η c as well as η c mass and width. Taking into account an asymmetric photon lineshape we obtained Γ 0 γ ηc = 2.98 ± 0.18 +0.15 −0.33 keV, M ηc = 2983.5 ± 1.4 +1.6 −3.6 MeV/c 2 , Γ ηc = 27.2 ± 3.1 +5.4 −2.6 MeV.
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