Related papers: Pion transitions from \chi_{cJ} to \eta_c
It is pointed out that the decay of the recently observed charmonium eta_c^prime resonance, eta_c^prime -> eta_c pi pi is simply related to the well studied decay psi^prime -> J/psi pi pi and can thus be used for absolute normalization of…
Hadronic transitions of the chi(cj)(1P) states have not been studied yet. We calculate the rate of the hadronic transition chi(c1)(1P) to eta(c) plus two pions in the framework of QCD multipole expansion. We show that this process can be…
We consider transitions from the resonance X(3872) to the chi_{cJ} states of charmonium with emission of one or two pions as a means of studying the structure of the X resonance. We find that the relative rates for these transitions to the…
In this article, we study the three-pion $B_c$-decays $B_c^+ \to J/\psi\, \pi^+\pi^-\pi^+$, $\eta_c\, \pi^+\pi^-\pi^+ $ with dominance of the intermediate axial-vector meson $a_1(1260)$ and vector meson $\rho(770)$ in the $\pi^+\pi^-\pi^+$…
The $B_{c}$ ${\to}$ $J/{\psi}{\pi}$, ${\eta}_{c}{\pi}$ decays are studied in the scheme of the QCD factorization approach. The branching ratios are calculated with the asymptotic distribution amplitude of the pion. The charm quark mass…
We calculate the branching ratios of the yet unmeasured eta' decays into four pions, based on a combination of chiral perturbation theory and vector-meson dominance. The decays eta' --> 2(pi+ pi-) and eta' --> pi+ pi- 2pi0 are P-wave…
We show that in the transitions psi' -> h_c \pi^0 and eta_c' -> chi_{c0} pi^0 the contributions from charmed meson loops are highly suppressed, in contrast to various other charmonium decays. We calculate the width of the psi' -> h_c pi^0,…
Hadronic transitions of $\chi_{cJ}\to \eta_{c}\pi^{+}\pi^{-}$ (J=0, 1, 2) are searched for using a sample of $1.06\times 10^{8}$ $\psi(3686)$ events collected with the BESIII detector at the BEPCII storage ring. The $\etac$ is reconstructed…
Utilizing $(2712.4 \pm 14.3) \times 10^6$ $\psi(3686)$ events collected with the BESIII detector at the BEPCII collider, we search for the hadronic transition process $\chi_{c1} \to \pi^+\pi^-\eta_c$ following the decay $\psi(3686)\to…
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…
We present a study of the P-wave spin -triplet charmonium chi_{cJ} decays (J=0,1,2) into pi^0 pi^0 pi^0 pi^0. The analysis is based on 106 million \psiprime decays recorded with the BESIII detector at the BEPCII electron positron collider.…
We investigate the theoretical uncertainties of $P$-wave charmonium decays into two pions, $\chi_{\c J}\rightarrow \pi^+\pi^-$, $\pi^0\pi^0$. Constraining the pion distribution-amplitude from the recent precise data on $F_{\pi\gamma}(Q^2)$,…
The $W$-exchange process $B_{s}$ ${\to}$ ${\eta}_{c}(J/{\psi})D$ is studied with the perturbative QCD approach. Three kinds of wave functions for $B_{s}$ meson and two forms of wave functions for charmonium are considered. It is estimated…
Two-pion transitions in charmonium and bottomonium are considered with the leading relativistic effects taken into account. The contribution of the chromo- magnetic interaction of the charmed quarks to the amplitude of the decay $\psi(2S)…
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…
The decays of eta_c to K^+K^-2(pi^+pi^-) and 3(pi^+pi^-) are observed for the first time using a sample of 5.8X10^7 J/\psi events collected by the BESII detector. The product branching fractions are determined to be B(J/\psi-->gamma…
The electromagnetic and pionic transitions in mesons with heavy flavor quarks are calculated within the framework of the covariant Blankenbecler-Sugar equation. The M1 transitions in the charmonium system are shown to be sensitive to the…
Recent BABAR results on two-photon processes are presented. A high statistics study of the two-photon production of the charmonium states eta_c and eta_c(2S) is performed. The mass and width of eta_c and eta_c(2S) are measured; the ratio of…
We investigated the pionic transitions between the $X_2$ [spin-2 partner of the $X(3872)$] and $\chi_{c1,2}$ using a nonrelativistic effective field theory. The $X_2$ is assumed to be a bound state of the $D^{*}$ and $\bar{D}^*$ mesons and…
We present a lattice QCD study of dilepton production in charmonium transitions, specifically focusing on the $1^{+-} \to 0^{-+}$ and $1^{++} \to 1^{--}$ processes: $h_c \to \eta_c \ell^+ \ell^-$ and $\chi_{c1} \to J/\psi \ell^+ \ell^-$,…