Related papers: Charmonium decays: J/psi --> e+e- and eta_c --> ga…
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 investigate E1 radiative transitions within charmonium in a relativistic approach based on light-front QCD. In quantum field theory, two sets of processes are pure E1: $\chi_{c0} \to J/\psi \gamma$ ($\psi\to \chi_{c0}\gamma$) and $h_c…
Using data acquired with the CLEO-c detector at the CESR e+e- collider, we measure branching fractions for J/psi, psi(2S), and psi(3770) decays to gamma pi0, gamma eta, and gamma eta'. Defining R_n = B[ psi(nS)-->gamma eta ]/B[…
We show that perturbation theory may give reasonable numbers for the decays of the bottomonium and charmonium ground states to $e^+e^-$ and to $\gamma\gamma$. To reach this conclusion it is important to perform the resummation of logs. In…
We study $O(\alpha_sv^2)$ corrections to decays of $^1S_0$ heavy quarkonium into light hadrons and two photons within the framework of nonrelativistic QCD, and find these $O(\alpha_sv^2)$ corrections to have significant contributions…
Decays $J/\psi\to B\bar B$ into octet baryon-antibaryons pairs are studied within the QCD factorisation framework. The next-to-leading power correction to the leading-order decay amplitude is calculated for the first time. The…
We present the results of our lattice QCD study of the hadronic matrix elements relevant to the physical radiative J/psi -> eta_c gamma and hc -> eta_c gamma decays. From computations with Nf=2 dynamical quark in twisted mass QCD at four…
Recent results on charmonia decays at BES/BEPC are reported, including the observation of psi'-->K_S K_L, psi'--> Vector + Tensor for the measurement of the relative phase between the strong and electromagnetic decays of psi' and a test of…
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…
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…
It is interesting to investigate the OZI-forbidden radiative orthoquarkonium decays $J/\psi\to \gamma\pi^0, \gamma\eta$ and $\gamma\eta'$ in perturbative QCD. In this work without the approximations adopted in literature we carry out a full…
We calculate the J/{\psi} mass, leptonic width and radiative decay rate to \gamma \eta_c from lattice QCD including u, d and s quarks in the sea for the first time. We use the Highly Improved Staggered Quark formalism and nonperturbatively…
Quarkonium decays are studied in the charmonium model. Relativistic corrections, higher-order perturbative QCD corrections and non- perturbative contributions are discussed. Recent measurements of charmonium annihilation rates are used to…
We apply perturbative QCD to the radiative decays of charmonia $J/\psi$ and $\chi_{cJ}$ into light mesons. We perform a complete numerical calculation for the quark-gluon loop diagrams involved in these processes. The calculated $J/\psi$…
We consider a different power counting in potential NRQCD by incorporating the static potential exactly in the leading order Hamiltonian. We compute the leading relativistic corrections to the inclusive electromagnetic decay ratios in this…
The decay rates of P-wave heavy quarkonia to light hadrons are presented to leading order in $v^2$ and next-to-leading order in $\alpha_s$. They include contributions from both the color-singlet component and the color-octet component of…
We present an evaluation of heavy quarkonium states (bottomium and charmonium) from first principles. We use tree-level QCD (including relativistic corrections) and the full one-loop potential; nonperturbative effects are taken into account…
Recent results from BES and CLEOc experiments on charmonium decays using J/psi, psi' and psi'' data samples collected in e+e- annihilation are reviewed, including the measurement of the relative phase between strong and electromagnetic…
Nonrelativistic quark models of charmonia are tested by comparison of theoretical charmonium decay constants, form factors, and $\gamma\gamma$ widths with experiment and lattice gauge computations. The importance of relativistic effects, a…
In the framework of instantaneous Bethe-Salpeter equation, according to the $J ^ {PC}$ of quarkonia, we find that their wave functions all contain multiple partial waves, rather than pure waves. In the radiative electromagnetic transitions…