اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMeasurement of the leptonic decay width of $J/psi$ using initial state radiation
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Using a data set of 2.93 fb$^{-1}$ taken at a center-of-mass energy of $sqrt{s}$ = 3.773 GeV with the BESIII detector at the BEPCII collider, we measure the process $e^+e^-rightarrow J/psigammarightarrow mu^+mu^-gamma$ and determine the product of the branching fraction and the electronic width $mathcal B_{mumu}cdot Gamma_{ee} = (333.4 pm 2.5_{rm stat} pm 4.4_{rm sys})$~eV. Using the earlier-published BESIII result for $mathcal B_{mumu}$ = (5.973 $pm$ 0.007$_{rm stat}$ $pm$ 0.037$_{rm sys}$)%, we derive the $J/psi$ electronic width $Gamma_{ee}$~= (5.58 $pm$ 0.05$_{rm stat}$ $pm$ 0.08$_{rm sys}$) keV.
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We report a new precise determination of the leptonic widths of the J/psi meson performed with the KEDR detector at the VEPP-4M $e^{+}e^{-}$ collider. The measured values of the J/psi parameters are: Gamma_{ee}timesGamma_{ee}/Gamma = 0.3323 pm 0.0064
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