Di-electron and two-photon widths in charmonium

Abstract

The vector and pseudoscalar decay constants are calculated in the framework of the Field Correlator Method. Di-electron widths: ${\Gamma }_{ee}(J/\psi )=5.41$ keV, ${\Gamma }_{ee}({\psi }^{\prime }(3686))=2.47$ keV, ${\Gamma }_{ee}({\psi }^{\prime \prime }(3770))=0.248$ keV, in good agreement with experiment, are obtained with the same coupling, ${\alpha }_s=0.165$, in QCD radiative corrections. We show that the larger ${\alpha }_s=0.191\pm 0.004$ is needed to reach agreement with experiment for ${\Gamma }_{\gamma \gamma }({\eta }_c)=7.22$ keV, ${\Gamma }_{\gamma \gamma }(\chi {(}^3{P}_0))=3.3$ keV, ${\Gamma }_{\gamma \gamma }(\chi {(}^3{P}_2))=0.54$ keV, and also for $\Gamma (J/\psi \to 3g)=59.5$ keV, $\Gamma (J/\psi \to \gamma 2g)=5.7$ keV. Meanwhile even larger ${\alpha }_s=0.238$ gives rise to good description of $\Gamma ({\psi }^{\prime }\to 3g)=52.7$ keV, $\Gamma ({\psi }^{\prime }\to \gamma 2g)=3.5$ keV, and provides correct ratio of the branching fractions: $\frac{\mathcal{B}(J/\psi \to lighthadrons)}{\mathcal{B}({\psi }^{\prime }\to lighthadrons)}=\mathrm{0.24.}$

8 pages, no figures

References in corpus (3)

• Observation of Two Resonant Structures in e+e- to pi+ pi- psi(2S) via Initial State Radiation at Belle
• Decay constants of the heavy-light mesons from the field correlator method
• Masses of the η_c(nS) and η_b(nS) mesons

Cited by in corpus (1)

• The $\mathbf{S}-\mathbf{D}$ mixing and di-electron widths of higher charmonium $1^{--}$ states