Related papers: Pion transitions from \chi_{cJ} to \eta_c

Productions and decays of spin-singlet $S,P-$wave charmonium states, $\eta_{c}^{'}$ and $h_{c} (^{1}P_{1})$, in the $e^+ e^-$ annihilations are considered in the QCD multipole expansion with neglecting nonlocality in time coming from the…

The QCD multipole expansion (QCDME) is based on the quantum field theory, so should be more reliable. However, on another aspect, it refers to the non-perturbative QCD , so that has a certain application range. Even though it successfully…

Using a sample of 2.59 x 10^7$ psi(2S) decays collected by the CLEO--c detector, we present results of a search for the decay chain psi(2S) -> pi^0 h_c, h_c -> n(pi^+ pi^-) pi^0, n=1,2,3. We observe no significant signals for n=1 and n=3…

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…

Using a data sample of $2.25\times10^{8}$ $J/\psi$ events collected with the BESIII detector, we present the first observation of the decays of $\eta_{c}$ mesons to $\Sigma^{+}\bar{\Sigma}^{-}$ and $\Xi^{-}\bar{\Xi}^{+}$. The branching…

Based on $\psi(3686)$ decays of 106 million, the 1.31 billion J/psi events and a data sample of $\psi(3770)$ with $2.9~fb^{-1}$ integrated luminosity, many analyses are performed. Exclusively baryonic decays of the $\psi(3770)$, the…

Based on $2.7 \times 10^9~\psi(3686)$ decays collected with the BESIII detector, the radiative decay $\psi(3686)\to\gamma2(\pi^{+}\pi^{-})\eta$ is investigated to measure properties of S- and P-wave charmonium states. The branching fraction…

The pion-to-proton ratio is identified as a potential signal for a non-equilibrium first-order chiral phase transition in heavy-ion collisions, as the pion multiplicity is directly related to entropy production. To showcase this effect, a…

I sketch how long wavelength modes of the pion field can be amplified during the QCD phase transition. If nature had been kinder, and had made the pion mass significantly less than the critical temperature for the transition, then this…

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…

We derive expressions for pion electroproduction amplitudes in the 1/N_c expansion of QCD, and obtain from them linear relations between the electromagnetic multipole amplitudes that hold at all energies. The leading-order relations in…

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…

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…

In the framework of Chiral Perturbation Theory including photons, we found that the contribution of the photon exchange between two intermediate charged Kaons to the slope parameter of the decay (\eta\rightarrow 3\pi^{0}) amounts to…

Experimental and theoretical progress concerning the rare decay \pi^0 \to e^+e^- is briefly reviewed. It includes the latest data from KTeV and a new model independent estimate of the decay branching which show the deviation between…

Using 22.7 million BBbar events recorded with the BABAR detector, the inclusive branching fractions for the production of J/psi, psi(2S) and Chi_c in B decays are presented. Combining the charmonium state with a K+-, K0, K*+-, K*0 or…

It is shown that the rates of the decays Upsilon(1^3D_1) -> eta Upsilon(1S) and Upsilon(1^3D_2) -> eta Upsilon(1S) should be comparable to and likely exceed that of the recently discussed in the literature two-pion transition Upsilon(1D) ->…

In this talk, recent measurements of charmonium decays of BESIII are presented. Using 448 million $\psi(3686)$ events collected with the BESIII detector, the branching fractions of the decays $\chi_{cJ} \to \phi \phi (J=0,1,2)$ have been…

In this work, we explore the $P$-wave resonance contributions to the three-body charmonium decays of $B_c\to \Psi (V\to) P_1P_2$ using the perturbative QCD formalism at leading order, where $\Psi$ denotes a $S$-wave charmonium state, such…

Using a data sample of $(448.1\pm2.9)\times10^{6}$ $\psi(3686)$ decays collected by the BESIII detector at the Beijing Electron Positron Collider (BEPCII), we observe the decays $\chi_{cJ}\to \phi\phi\eta~(J=0,~1,~2)$, where the $\chi_{cJ}$…