[en] The status of the experiment on the precise τ lepton mass measurement running at the VEPP-4M collider with the KEDR detector is reported. The mass value is evaluated from the τ⁺τ^- cross section behaviour around the production threshold. The preliminary result based on 6.7 pb^-1 of data is m_τ=1776.80_-0.23^+0.25±0.15 MeV. Using 0.8 pb^-1 of data collected at the ψ^' peak the preliminary result is also obtained: Γ_ee.B_ττ(ψ^')=7.2±2.1 eV

[en] This study was initiated by the Belle detector upgrade plan including the replacement of the CsI(Tl) crystals in the endcaps by the pure CsI. Within this work five samples of pure CsI crystals were irradiated by the beam of 0.6MeVγ-quanta. The absorbed dose accumulated in several runs reached 55 krad for two samples and 13 krad for three others. Four of these samples were found to satisfy the super B-factory conditions. The light output reduction for them does not exceed 15% at 13 krad of absorbed dose. One sample had poor radiation resistance.

[en] A new high precision measurement of the J/ψ- and ψ/'-meson masses has been performed at the VEPP-4M collider using the KEDR detector. The resonant depolarization method has been employed for the absolute calibration of the beam energy. The following mass values have been obtained:M_J/ψ = 3096.917 ± 0.010 ± 0.007 MeV, M_ψ'= 3686.111 ± 0.025 ± 0.009 MeV. The relative measurement accuracy has reached 4·10-6 for J/ψ and 7·10-6 for ψ', approximately 3 times better than in the previous precise experiments. The description of the experiment and the error analysis can be found in hep-ex/0306050, Phys. Lett. B573 (2003) 63-79

[en] New measurements of ψ(2S), ψ(3770) and D meson masses are presented. The results of the scans performed were used for determination of the products Γ_eexΓ_ee/Γ for J/ψ and Γ_eexΓ_μμ/Γ for ψ(2S)

[en] The status of the experiment on the precise τ lepton mass measurement running at the VEPP-4M collider with the KEDR detector is reported. The mass value is evaluated from the τ⁺τ^- cross section behavior around the production threshold. The preliminary result based on 15.2 pb^-1 of data is m_τ=1776.69_-0.19^+0.17±0.15 MeV

[en] The status of the experiment on the precise τ lepton mass measurement running at the VEPP-4M collider with the KEDR detector is reported. The mass value is evaluated from the τ⁺τ^- cross section behavior around the production threshold. The preliminary result based on 15.2 pb^-1 of data is m_τ=1776.69_-0.19^+0.17±0.15 MeV.

[en] KEDR is a general-purpose detector for experiments at the VEPP-4M e⁺e^--collider in the energy range 2E=2.0-12 GeV. All detector subsystems (except the aerogel Cherenkov counters) have been installed into the detector at VEPP-4M. Some preliminary data have been taken in the energy region of the J/Ψ meson. The tuning of the detector and the VEPP-4M collider is in progress. Preliminary results on the detector performance are presented. The future experimental program for the KEDR detector is discussed

[en] We present preliminary results of a new high-precision determination of the τ lepton mass performed with the KEDR detector at the VEPP-4M e⁺e^- collider. These results are compared to two recent τ lepton mass measurements at Belle and BaBar.

[en] The products of the electron width of the J/ψ meson and the branching fraction of its decays to the lepton pairs were measured using data from the KEDR experiment at the VEPP-4M electron-positron collider. The results are Γ_eexΓ_ee/Γ=0.3323±0.0064(stat.)±0.0048(syst.) keV, Γ_eexΓ_μμ/Γ=0.3318±0.0052(stat.)±0.0063(syst.) keV. Their combinations Γ_eex(Γ_ee+Γ_μμ)/Γ=0.6641±0.0082(stat.)±0.0100(syst.) keV, Γ_ee/Γ_μμ=1.002±0.021(stat.)±0.013(syst.) can be used to improve the accuracy of the leptonic and full widths and test leptonic universality. Assuming eμ universality and using the world average value of the lepton branching fraction, we also determine the leptonic Γ_ll=5.59±0.12 keV and total Γ=94.1±2.7 keV widths of the J/ψ meson.

[en] We report results of experiments performed with the KEDR detector at the VEPP-4M e⁺ e^- collider.They include precise measurement of the D⁰ and D^± meson masses, determination of the ψ(3770) resonance parameters,and a search for narrow resonances in e⁺ e^- annihilation at center-of-mass energies between 1.85 and 3.1 GeV. (authors)