E.A. Kuper

A high precision measurement of the ϒ, ϒ′ and ϒ″-meson masses

Abstract An experiment has been performed at the storage ring VEPP-4 using the MD-1 detector. The resonance depolarization method has been employed for the absolute calibration of the beam energy. This has allowed the accuracy of the mass measurement to be improved by a factor of ten. The following mass values of ϒ, ϒ′ and ϒ″ -mesons have been obtained: M ( ϒ )=9460.6±0.4 MeV, M ( ϒ ′)=10023.8±0.5 MeV, M ( ϒ ″)=10355.5±0.5 MeV.

High precision mass measurements in Ψ and ϒ families revisited

Abstract High precision mass measurements in Ψ and ϒ families performed in 1980–1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited. The corrections for the new value of the electron mass are presented. The effect of the updated radiative corrections has been calculated for the J / Ψ (1 S ) and Ψ (2 S ) mass measurements.

A high precision measurement of the υ-meson mass

Abstract A high precision measurement of the υ-meson mass has been performed at the storage ring VEPP-4 using the MD-1 detector. The resonance depolarization method has been used for the absolute calibration of the beam energy that allowed to improve the accuracy of υ-mass measurement by a factor of ten. The following mass value has been obtained: M = 9459.7 ± 0.6 MeV.

Measurement of Γee(J/ψ)⋅B(J/ψ→e+e−)Γee(J/ψ)⋅B(J/ψ→e+e−) and Γee(J/ψ)⋅B(J/ψ→μ+μ−)Γee(J/ψ)⋅B(J/ψ→μ+μ−)

The products of the electron width of the J/ψJ/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 n nΓee×Γee/Γ=0.3323±0.0064(stat.)±0.0048(syst.) keV,Γee×Γee/Γ=0.3323±0.0064(stat.)±0.0048(syst.) keV, n n n nΓee×Γμμ/Γ=0.3318±0.0052(stat.)±0.0063(syst.) keV.Γee×Γμμ/Γ=0.3318±0.0052(stat.)±0.0063(syst.) keV. n nTheir combinations n nΓee×(Γee+Γμμ)/Γ=0.6641±0.0082(stat.)±0.0100(syst.) keV,Γee×(Γee+Γμμ)/Γ=0.6641±0.0082(stat.)±0.0100(syst.) keV, n n n nΓee/Γμμ=1.002±0.021(stat.)±0.013(syst.)Γee/Γμμ=1.002±0.021(stat.)±0.013(syst.) n ncan be used to improve the accuracy of the leptonic and full widths and test leptonic universality. n nAssuming eμ universality and using the world average value of the lepton branching fraction, we also determine the leptonic Γll=5.59±0.12 keVΓll=5.59±0.12 keV and total Γ=94.1±2.7 keVΓ=94.1±2.7 keV widths of the J/ψJ/ψ meson.The products of the electron width of the J/psi 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 nGamma_{ee}(J/psi)*Br(J/psi->e^+e^-)=(0.3323pm0.0064pm0.0048) keV, nGamma_{ee}(J/psi)*Br(J/psi->mu^+mu^-)=(0.3318pm0.0052pm0.0063) keV. nTheir combinations nGamma_{ee}times(Gamma_{ee}+Gamma_{mumu})/Gamma=(0.6641pm0.0082pm0.0100) keV, nGamma_{ee}/Gamma_{mumu}=1.002pm0.021pm0.013 can be used to improve theaccuracy of the leptonic and full widths and test leptonic universality. Assuming emu universality and using the world average value of the lepton branching fraction, we also determine the leptonic Gamma_{ll}=5.59pm0.12 keV and total Gamma=94.1pm2.7 keV widths of the J/psi meson.

High Precision Measurement of the

Abstract A high precision measurement of the υ-meson mass has been performed at the storage ring VEPP-4 using the MD-1 detector. The resonance depolarization method has been used for the absolute calibration of the beam energy that allowed to improve the accuracy of υ-mass measurement by a factor of ten. The following mass value has been obtained: M = 9459.7 ± 0.6 MeV.