Measurement of J/psi leptonic width with the KEDR detector

• Published in: arXiv.org 2011-10
• Main Authors: Anashin, V V, Aulchenko, V M, Baldin, E M, Barladyan, A K, A Yu Barnyakov, M Yu Barnyakov, Baru, S E, I Yu Basok, Beloborodova, O L, Blinov, A E, Blinov, V E, Bobrov, A V, Bobrovnikov, V S, Bogomyagkov, A V, Bondar, A E, Buzykaev, A R, Eidelman, S I, Grigoriev, D N, Glukhovchenko, Yu M, Gulevich, V V, Gusev, D V, Karnaev, S E, Karpov, G V, Karpov, S V, Kharlamova, T A, Kiselev, V A, Kolmogorov, V V, Kononov, S A, K Yu Kotov, Kravchenko, E A, Kudryavtsev, V N, Kulikov, V F, G Ya Kurkin, Kuper, E A, Levichev, E B, Maksimov, D A, Malyshev, V M, Maslennikov, A L, Medvedko, A S, Meshkov, O I, Mishnev, S I, Morozov, I I, N Yu Muchnoi, Neufeld, V V, Nikitin, S A, Nikolaev, I B, Okunev, I N, Onuchin, A P, Oreshkin, S B, Orlov, I O, Osipov, A A, Peleganchuk, S V, Pivovarov, S G, Piminov, P A, Petrov, V V, Poluektov, A O, Prisekin, V G, Ruban, A A, Sandyrev, V K, Savinov, G A, Shamov, A G, Shatilov, D N, Shwartz, B A, Simonov, E A, Sinyatkin, S V, Skrinsky, A N, Smaluk, V V, Sokolov, A V, Sukharev, A M, Starostina, E V, Talyshev, A A, Tayursky, V A, Telnov, V I, Tikhonov, Yu A, K Yu Todyshev, Tumaikin, G M, Usov, Yu V, Vorobiov, A I, Yushkov, A N, Zhilich, V N, Zhulanov, V V, Zhuravlev, A N
• Format: Article
• Language: English
• Subjects: Leptons
• ISSN: 2331-8422

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}\times\Gamma_{ee}/\Gamma = 0.3323 \pm 0.0064 (stat.) \pm 0.0048 (syst.) keV \Gamma_{ee}\times\Gamma_{\mu\mu}/\Gamma=0.3318 \pm 0.0052 (stat.) \pm 0.0063 (syst.) keV. Assuming \(e\mu\) universality and using the table value of the branching ratios the leptonic \Gamma_{ll}= 5.59 \pm 0.12 keV width and the total \Gamma=94.1 \pm 2.7 keV widths were obtained. We also discuss in detail a method to calculate radiative corrections at a narrow resonance.