Related papers: Shedding light on charmonium

In this paper we have analyzed the production of pair charmonium mesons in the reactions $e^+ e^- \to J/ \Psi \chi_{c0}, e^+ e^-\to \Psi(2S) \chi_{c0}$ at energy $\sqrt s = 10.6$GeV in the framework of the light cone formalism. In…

We build a "bottom-up" holographic model of charmonium by matching the essential spectral data. We argue that this data must include not only the masses but also the decay constants of the J/psi and psi' mesons. Relative to the "soft-wall"…

At CLEO, charmonium spectroscopy is pursued both thorugh e+e- annihilation data taken in the Upsilon region and more recently at psi(2S). A nmber of first observations (eta_c', h_c, pi and K form factors) have been made, and numerous high…

The form factors of the $K^+ \to \gamma$ transition are studied in the light-front quark model and chiral perturbation theory of $O(p^6)$. The decay spectrum of $K^+ \to e^+ \nu_{e}\gamma$, dominated by the structure dependent contribution,…

Electromagnetic form factors serve to explore the intrinsic structure of nucleons and their strangeness partners. With electron scattering at low energies the electromagnetic moments and radii of nucleons can be deduced. The corresponding…

We study selected meson transition processes and associated form factors within a model of QCD based on the Dyson--Schwinger equations truncated to ladder-rainbow level. The infrared structure of the ladder-rainbow kernel is described by…

We analyze the exclusive charmonium $J/\psi+\eta_c$ pair production in $e^+e^-$ annihilation using the nonfactorized perturbative QCD and the light-front quark model(LFQM) that goes beyond the peaking approximation. We effectively include…

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…

This is a short review of some hard two-photon processes: $\\ a) \,\,\gamma\gamma\to {\overline P}_1 P_2,\,\, {\overline P}_1 P_2= \{\pi^+\pi^-, K^+ K^-, K_S K_S, \pi^o\pi^o, \pi^o\eta\}\,, \\ b) \,\,\gamma\gamma\to V_1 V_2,\,\, V_1…

Radiative corrections to E1 matrix elements for ns-np transitions in the alkali metal atoms lithium through francium are evaluated. They are found to be small for the lighter alkalis but significantly larger for the heavier alkalis, and in…

In this paper the processes $e^+ e^- \to J/\Psi J/\Psi, J/\Psi \psi', \psi' \psi'$ are considered in the framework of light cone formalism. An important distinction of this approach in comparison to the approaches used in other papers is…

Measurements of branching fractions for nine different final states, based on a data sample of approximately 4 million psi(2S) events collected with the BESI detector at the BEPC, are reported. Using the same event sample, radiative decays…

The processes of P-wave Quarkonium exclusive decays to two mesons are investigated, in which the final state vector mesons with various polarizations are considered separately. In the calculation, the initial heavy quarkonia are treated in…

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 measurements of the charmonium state $h_c(^1P_1)$ made with 106M $\psi'$ events collected by BESIII at BEPCII. Clear signals are observed for $\psi'\to\pi^0 h_c$ with and without the subsequent radiative decay…

Some new results on magnetic dipole (M1) transitions in heavy quarkonium from nonrelativistic effective field theories of QCD are briefly reported. This model-independent approach not only facilitates a systematic and lucid way to…

In this article, we study the radiative decays among the charmonium states with the heavy quark effective theory, and make predictions for the ratios among the radiative decay widths of an special multiplet to another multiplet. The…

We demonstrate how the elementary amplitudes $\gamma N\to \Psi N$, the amplitude of the nondiagonal $J/\psi N\Leftrightarrow \psi' N$ transition, and the total $J/\psi N$ and $\psi' N$ cross sections can be determined from measurements of…

We extend our original study in Ref. [1] on the production of $C=+$ charmonium states $X=\eta_c(1S/2S)$ and $\chi_{cJ}(1P/2P)$ in $e^+e^-\to\gamma~+~X$ at B factories to the BEPCII/BESIII energy region with $\sqrt{s}=4.0\mbox{-}5.0$ GeV. In…

The $1^1D_2 (c\bar c)$ state is the ground state of spin-singlet D-wave charmonia. Although it has not been found yet, the experimental data accumulate rapidly. This charmonium attracts more and more attention, especially when the BaBar…