Related papers: Radiative decays in charmonium beyond the p/m appr…
We study the charmonium spectrum using a complete one gluon exchange approach based on a phenomenological relativistic $q\bar{q}$ potential model with Dirac spinors in momentum space. We use phenomenological screening factors to include…
In the framework of the non relativistic quark model, an exhaustive study of radiative transitions in mesons is performed. The emphasis is put on several points. Some traditional approximations (long wave length limit, non relativistic…
Charmonium productions in $p-p$ and $A-B$ collisions have been estimated within the ambit of colour evaporation model (CEM). The model parameters have been fixed by fitting the theoretical results with CDF data. The method is then applied…
The analysis of the $\pi\gamma$ transition form factor provides severe constraints on the pion's wave function. This information is used to examine charmonium decays into two pions critically. It will be argued that the standard…
Calculations of form factor for the radiative decays $V\rightarrow P\gamma^{*}$ process are performed in the framework of an instant form of relativistic quantum mechanics. The electromagnetic current operator for this decay is constructed.…
We study the production of charmonium hybrids in B decays. We use the operator product expansion and nonrelativistic QCD to organize the various contributions to this process. We express the decay rate in terms of a few matrix elements…
We derive the imaginary part of the potential NRQCD Hamiltonian up to order 1/m^4, when the typical momentum transfer between the heavy quarks is of the order of Lambda_{QCD} or greater, and the binding energy E much smaller than…
Radiative decays X --> psi(1S) + gamma and X --> psi(2S) + gamma might be expected to have a ratio of branching fractions following the phase space volumes ratio. However data suggest the opposite, indicating a value for R=B(X --> psi^prime…
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 $P$…
Based on the data samples collected at the energies of $J/\psi$, $\psi(3686)$, $\psi(3770)$ and $\psi(4040)$ resonances with the BESIII detector at the BEPCII storage ring, we present charmonium decays in two aspects. One is the search for…
In this work, we calculate the amplitudes of the processes $c\bar c({^3P_J}) \rightarrow DD,DD^*, D^*D^* \rightarrow c\bar c({^3P_J})$ in the leading order of the nonrelativistic expansion. The imaginary parts of the amplitudes are…
Using the $R$-matrix approach we calculate the radiative width for a resonance decaying to a bound state through electric dipole, $E1$, transitions. The total radiative width is determined by the interference of the nuclear internal and…
The theoretical explanations about the ``Rho-pi puzzle'' in charmonium decays are reviewed extensively, and the comparison of theoretical predications with experimental data is made whenever possible. Three methods to estimate the ratio of…
The extraction of decay parameters using lattice techniques is a computationally expensive task, requiring several volumes and group irreps to relate the spectrum on a lattice simulation to the infinite volume scattering. In this project we…
We propose the initial single chiral particle emission mechanism, with which the hidden-charm di-kaon decays of higher charmonia and charmonium-like states are studied. Calculating the distributions of differential decay width, we obtain…
Charmonium production and suppression in heavy-ion collisions at relativistic energies is investigated within different models, i.e. the comover absorption model, the threshold suppression model, the statistical coalescence model and the…
With usage of the Low theorem the general expression for amplitude of radiative kaon decay \k+ \to \pi+\pi0\gamma is determined.
Results are reported based on samples of 58 million $\jpsi$ and 14 million $\psip$ decays obtained by the BESII experiment. Improved branching fraction measurements are determined, including branching fractions for $\jpsi\to\ppp$, $\psip\ra…
Radiative muon decay in the kinematics similar to the neutrinoless decay $\mu\to e\gamma$ is considered. Radiative corrections due to 1-loop virtual photons and emission of additional soft or hard photons are taken into account. Analytical…
The nature of resonances and excited states near decay thresholds is encoded in scattering amplitudes, which can be extracted from single-particle and multiparticle correlators in finite volumes. Lattice calculations have only recently…