Related papers: Two-Photon Widths of the chi_cJ States of Charmoni…

Results are reported based on samples of 58 million $J/\psi$ and 14 million $\psi(2S)$ decays obtained by the BESII experiment. Improved branching fraction measurements are determined, including branching fractions for…

The decays $\chi_{c1} \rightarrow J/\psi \mu^+ \mu^-$ and $\chi_{c2} \rightarrow J/\psi \mu^+ \mu^-$ are observed and used to study the resonance parameters of the $\chi_{c1}$ and $\chi_{c2}$ mesons. The masses of these states are measured…

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…

We propose to measure the two--photon capture mode of pionic hydrogen using the RMC pair spectrometer at the TRIUMF cyclotron. Currently, only an experimental upper limit of B.R.<= 5.5E-4 is available for the two-gamma capture mode. Our new…

In this work, a formalism is presented for the helicity amplitude analysis of the decays $\psi(2S) \to \gamma_1 \chi_{cJ},~ \chi_{cJ} \to \gamma_2 V (V=\rho^0,~\phi,~\omega)$~(the subscript 1,2 is used to distinguish the two radiative…

We systematically investigate the mass spectrum and two-body open-charm strong decays of charmonium states in a coupled-channel model where the $^3P_0$ quark-antiquark pair creation mechanism is employed. The results of masses, mass shifts,…

By neglecting the relative quark momenta in the propagator term, the two-photon and two-gluon decay amplitude of heavy quarkonia states can be written as a local heavy quark field operator matrix element which could be obtained from other…

In this talk, I review the recent experimental results on charmonium spectroscopy from BESIII, Belle, BaBar and CLEOc. Below the open-charm threshold, the masses and widths of spin-singlet states eta_c, eta_c(2S), h_c are measured with high…

Radiative decays of the radially excited charmonium resonance, \psi(2S), into \pi\pi, K Kbar and \eta\eta final states have been measured in a sample of 3.96 * 10^6 \psi(2S) events collected by the BES collaboration. The branching ratios…

Two-body open charm strong decays of the $2P$ and $3P$ charmonium states are studied by the Bethe-Salpeter(BS) method combined with the $^3P_0$ model. The wave functions and mass spectra of the $2P$ and $3P$ charmonium states are obtained…

The Particle Data Group has assigned the X(3915) meson, an omega J/psi mass peak seen in B-> omega J/psi decays and in two-photon fusion reactions gamma-gamma->omega J/psi, as the chi_{c0}(2P), the 2^3P_0 charmonium state. Here it is shown…

We search for the hadronic decay $\eta_c(2S)\to 2(\pi^+\pi^-)$ in the $\psi(3686)\to\gamma\eta_c(2S)$ radiative decay using $(27.12\pm 0.14)\times 10^8$ $\psi(3686)$ events collected by the BESIII detector at the BEPCII collider. No…

We estimate \Delta Gamma_d/\Gamma_d, including 1/m_b contributions and part of the next-to-leading order QCD corrections, and find it to be around 0.3%. We show the methods to measure \Delta Gamma_d/\Gamma_d by using at least two different…

We investigate a new method to probe the helicity of the photon emitted in the b -> s gamma transition. The method relies on the observation of interference effects between two resonance contributions, B -> K*(K gamma) gamma and B ->…

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,…

We calculate the E1 transition widths of higher vector charmonium states into the spin-triplet 2P states in three typical potential models, and discuss the possibility to detect these 2P states via these E1 transitions. We attempt to…

The cross sections for the hadroproduction of the Chi1 and Chi2 states of charmonium in proton-silicon collisions at sqrt{s}=38.8 GeV have been measured in Fermilab fixed target Experiment 771. The Chi states were observed via their…

The two photon transition of $\bar{c}c$ quarkonia are studied within a covariant approach based on the consistent truncation scheme of the quantum chromodynamics Dyson-Schwinger equation for the quark propagator and the Bethe--Salpeter…

We suggest that Bose statistics for photons can be tested by looking for decays of spin-1 bosons into two photons. The experimental upper limit on the decay $Z \rightarrow \gamma \gamma $ is used to establish for the first time the…

Using a data sample of $(2712.4 \pm 14.3) \times 10^{6}$ $\psi(3686)$ events collected with the BESIII detector operating at the BEPCII collider, we report the first observation of the decays $\chi_{cJ}\to 2K^+ 2K^- \omega$ and…