Evidence for ${\eta }_c\to \gamma \gamma$ and Measurement of $J/\psi \to 3\gamma$

Abstract

The decay of $J/\psi$ to three photons is studied using $\psi (3686)\to {\pi }^{+}{\pi }^{-}J/\psi$ in a sample of $1.0641\times 10^8$ $\psi (3686)$ events collected with the BESIII detector. Evidence of the direct decay of ${\eta }_c$ to two photons, ${\eta }_c\to \gamma \gamma$, is reported, and the product branching fraction is determined to be $\mathcal{B}(J/\psi \to \gamma {\eta }_c,{\eta }_c\to \gamma \gamma )=(4.5\pm 1.2\pm 0.6)\times 10^{-6}$, where the first error is statistical and the second is systematic. The branching fraction for $J/\psi \to 3\gamma$ is measured to be $(11.3\pm 1.8\pm 2.0)\times 10^{-6}$ with improved precision.

two-column 7 pages, 5 figures, 2 tables

References in corpus (4)

• Charmonium
• Precision Study of Positronium: Testing Bound State QED Theory
• Measurement of B(J/psi->eta_c gamma) at KEDR
• Precision measurements of positronium decay rate and energy level

Cited by in corpus (13)

• Precise determination of decay rates for ${\eta }_c\to \gamma \gamma$, $J/\psi \to \gamma {\eta }_c$ and $J/\psi \to {\eta }_c{e}^{+}{e}^{-}$ from lattice QCD
• First-principle calculation of ${\eta }_c\to 2\gamma$ decay width from lattice QCD
• Study on efficiency of event start time determination at BESIII
• Ward Identity of the Vector Current and the Decay Rate of ${\eta }_c\to \gamma \gamma$ in Lattice QCD
• Annihilation Rates of ${}^3{D}_2(2^{--})$ and ${}^3{D}_3(3^{--})$ Heavy Quarkonia
• Reconciling the nonrelativistic QCD prediction and the $J/\psi \to 3\gamma$ data
• Three Photon Decay of $J/\psi$ from Lattice QCD
• $\mathcal{O}({\alpha }_s{v}^2)$ corrections to hadronic decay of vector quarkonia
• Observation of the charmonium decay ${\eta }_c\to \gamma \gamma$ in $J/\psi \to \gamma {\eta }_c$
• Spectroscopy of heavy-heavy flavour mesons and annihilation widths of quarkonia
• Holographic quark masses and radiative decays of heavy vector mesons
• Lattice study of $J/\psi \to \gamma {\eta }_c$ using a method without momentum extrapolation
• Gauge invariant formulation of 3$\gamma$ decay of particle-antiparticle bound states