Speaker
Evgeny Baldin
(BINP)
Description
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 Γee(J/ψ)*Br(J/ψ->e+e-)=(0.3323 ± 0.0064 ± 0.0048) keV, Γee(J/ψ)*Br(J/ψ->µ+µ-)=(0.3318 ± 0.0052 ± 0.0063) keV.
Their combinations Γee*(Γee+Γµµ)/Γ=(0.6641 ± 0.0082 ± 0.0100) keV, Γee/Γµµ=1.002 ± 0.021 ± 0.013 can be used to improve the accuracy of the leptonic and full widths and test leptonic universality. Assuming e/µ universality and using the world average value of the lepton branching fraction, we also determine the leptonic Γll=5.59 ± 0.12 keV and total Γ=94.1 ± 2.7 keV widths of the J/ψ meson.
Author
Evgeny Baldin
(BINP)
Co-author
Collaboration KEDR
(BINP)
