相关论文: Radiative charmonium decays in a contact-interacti…
Using $(2712.4\pm14.3)\times10^{6}$ $\psi(3686)$ events collected with the BESIII detector at the BEPCII collider, the decay $\eta_c\to\gamma\gamma$ in $J/\psi\to\gamma\eta_c$ is observed. We determine the product branching fraction…
The lowest lying charmonium system $\eta_c$ has been observed for more than four decades. Studies of its production and decay properties provide an unique platform to investigate the inner structure of charmonium systems, hence improve our…
We use a simple perturbation theory argument and measurements of charmonium leptonic widths $\Gamma (\psi_{NS} \rightarrow e^+e^-)$ to estimate the ratio \mbox{$R_\circ \equiv {\vert \Psi _{\eta_{c1S}}(0) \vert}^2 /{\vert\Psi_{\psi_{1…
In the decays of $\eta_c\to\gamma\gamma$ and $J/\psi\to\gamma\eta_c$, there are discrepancies between the theoretical calculations and the PDG experimental values, referred to as the charmonium QCD puzzle. We observe the decay…
Using a sample of $(1310.6\pm7.0)\times10^6$ $J/\psi$ events recorded with the BESIII detector at the symmetric electron positron collider BEPCII, we report the observation of the decay of the $(1^1 S_0)$ charmonium state $\eta_c$ into a…
Using 24.5 million psi(2S) decays collected with the CLEO-c detector at CESR we present the most precise measurements of magnetic dipole transitions in the charmonium system. We measure B(psi(2S)->gamma eta_c) = (4.32+/-0.16+/-0.60)x10^-3,…
This review briefly outlines recent experimental results from the charmonium system. These include new measurements of the M1 radiative transition rates $B(\psi(1S,2S)\to\gamma\eta_c(1S))$; new insights into the mass of the $\eta_c(1S)$;…
We compute the hadronic matrix element relevant to the physical radiative decay $\eta_{c}(2S)\to J/\psi\gamma$ by means of lattice QCD. We use the (maximally) twisted mass QCD action with Nf=2 light dynamical quarks and from the…
The $\mathcal{V}\to\mathcal{P}\gamma$ and $\eta(\eta^\prime) \to \gamma\gamma$ decays are evaluated within a Dyson-Schwinger and Bethe-Salpeter equations framework (here $\mathcal{V}=\{\rho^{\pm},K^{\star\pm},\phi\}$ and…
Motivated by recent measurements of the radiative decay rates of the \emph{P}-wave spin singlet charmonium $h_c$ to the light meson $\eta$ or $\eta^\prime$ by the BESIII Collaboration, we investigate the decay rates of these channels at…
The $P$-wave charmonium decays $h_{c}\rightarrow\gamma\eta^{(\prime)}$ are revisited by taking into account relativistic corrections. The decay amplitudes are derived in the Bethe-Salpeter formalism, in which the involved one-loop integrals…
The study of electron-positron collisions at center-of-mass energies corresponding to charmonium production has reached new levels of sensitivity thanks to experiments by the BES and CLEO Collaborations. Final states $\gamma P$, where $P$…
Using the inclusive photon spectrum based on a data sample collected at the $J/\psi$ peak with the KEDR detector at the VEPP-4M $e^+e^-$ collider, we measured the rate of the radiative decay $J/\psi\to\gamma\eta_{\rm c}$ as well as…
The relation between the ratio Gamma_{ee}(psi')/Gamma_{ee}(J/psi) and Gamma_{2gamma}(eta_{c}')/Gamma_{2gamma}(eta_{c}), expressed in terms of the configuration mixing amplitudes induced by the contact spin-spin interaction of quarks in the…
By analyzing existing data on pseudoscalar charmonium decays, we obtain the ratio of the branching fractions of $\eta_c(2S)$ and $\eta_c$ decays into ten different final states with light hadrons. For the first time, we test the two…
Recently, the BESIII Collaboration reported two new decay processes $h_c(1P)\to \gamma \eta$ and $\gamma \eta^\prime$. Inspired by this measurement, we propose to study the radiative decays of $h_c$ via intermediate charmed meson loops in…
We study the processes gamma gamma -> K^0_S K pi and gamma gamma -> K+ K- pi+ pi- pi0 using a data sample of 519.2 fb-1 recorded by the BaBar detector at the PEP-II asymmetric-energy e+e- collider at center-of-mass energies near the…
We estimate the decay rates of $\eta_c\rightarrow 2\gamma$, $\eta_c'\rightarrow 2\gamma$, and $J/\psi\rightarrow e^+ e^-$, $\psi^\prime\rightarrow e^+e^-$, by taking into account both relativistic and QCD radiative corrections. The decay…
We study the form factors of the $\eta_c$ meson in the light-front quark model. We explicitly show that the transition form factor of $\eta_c \to \gamma^* \gamma$ as a function of the momentum transfer is consistent with the experimental…
We perform a lattice QCD calculation of the $\eta_c\to2\gamma$ decay width using a model-independent method that requires no momentum extrapolation of the off-shell form factors. This method also provides a straightforward and simple way to…