Related papers: Possible contributions to $e^+e^- \to J/\psi + \et…
Intermediate hadronic meson loop contributions to $J/\psi$, $\psi^\prime \to \gamma\eta_c$ ($\gamma\eta_c^\prime$) are studied apart from the dominant M1 transitions in an effective Lagrangian approach. Due to the property of the unique…
Based on a systematic investigation of $J/\psi(\psi^\prime)\to VP$, where $V$ and $P$ stand for light vector and pseudoscalar mesons, we identify the role played by the electromagnetic (EM) transitions and intermediate meson loop…
We calculate the cross sections for the processes $e^+e^-\to \jpsi \eta$ and $e^+e^-\to \jpsi \eta^\prime$ at various CM energies $\sqrt{s}$. We first predict these cross sections by combining NRQCD with LC factorization. The predicted…
With the new measurements of $J/\psi$ and $\psi^\prime\to \gamma\eta_c \ (\gamma\eta_c^\prime)$ from CLEO and BES-III Collaboration, we re-investigate the intermediate meson loop (IML) contributions to these radiative decays in association…
We reinvestigate the $J/\psi$ dissociation processes induced by the reactions with nucleons, $J/\psi + N \to \bar{D}^{(*)} + \Lambda_c$, in the meson-exchange model. Main constraints used in this work are vector-meson dominance and charm…
The total cross section of the process $e^+e^- \to \Lambda\bar{\Lambda}$ is calculated within the energy range close to the mass of $\psi(3770)$ charmonium state. Two different contributions were considered: the $D$-meson loop and the three…
It was argued long ago that eta_b could be observed through the eta_b => Jpsi(=> mu+ mu-) Jpsi(=> mu+ mu-) decay chain. Recent calculations indicate that the width of eta_b into two Jpsi is almost 3 orders of magnitude smaller than the one…
In this note we study the tensor and vector exchange contributions to the elastic reactions involving the pseudoscalars mesons $\pi^+ \pi^-$, $K^{+}K^{-}$ and $D^{+}D^{-}$. In the case of the tensor-exchange contributions we assume that an…
We reanalyze the dissociation process of the $J/\psi$ by $\pi$ and $\rho$ mesons into $D + \bar{D}$, $D^* + \bar{D}$, $D + \bar{D}^*$, and $D^* + \bar{D}^*$ within a meson exchange model. In addition to the dissociation mechanisms…
A detailed theoretical derivation of the cross sections of $e^+e^- \to e^+e^-$ and $e^+e^- \to \mu^+\mu^-$ around the $J/\psi$ resonance is reported. The resonance and interference parts of the cross sections, related to $J/\psi$ resonance…
Involving of elastic rescattering and annihilation of quark-antiquark pairs in a final state allows us to explain a dependence of ratio for cross sections of $\eta'$ and $\eta$ mesons versus transfer momentum in charge exchange reactions.…
We study the reaction $e^+e^-\to\bar DD$ near threshold in the $^3P_0$ non-relativistic quark model, including as intermediate states the $J/\psi$, $\psi(2S)$, $\psi(3770)$ and $\psi(4040)$ mesons. The work reveals that experimental data…
We study the decay process of $J/\psi\rightarrow e^+e^- \phi$ where the relatively clean electromagnetic (EM) transitions appear at leading order at tree level while the hadronic contributions only emerge via hadronic loop transitions. We…
We carry out a combined study of the isospin-violating decay $D_{s}^{*} \to D_{s} \pi^{0}$ and radiative decay $D^*_s\to D_s\gamma$ in an effective Lagrangian approach by taking into account the corrections from the one-loop transitions. By…
The cross section values of $J/\psi\ \eta_c$ and $J/\psi\ J/\psi$ production in $e^+e^-$ annihilation are estimated within one-loop approximation near $Z$ pole, as well as at higher energies. Both intermediate bosons, $\gamma$ and $Z$, are…
We perform a theoretical study of the $D_s^{+}\to \pi^{+}\pi^{+}\pi^{-}\eta$ decay. We look first at the basic $D_s^{+}$ decay at the quark level from external and internal emission. Then hadronize a pair or two pairs of $q\bar{q}$ states…
The effects of meson-exchange currents (MEC) are computed for the one-particle one-hole transverse response function for finite nuclei at high momentum transfers $q$ in the region of the quasielastic peak. A semi-relativistic shell model is…
We search for the reaction channel $e^+ e^- \to \eta\eta\,J/\psi$ in a data sample with center-of-mass energies from 4.226 to 4.950~GeV, which was collected by the BESIII detector operating at the Beijing Electron Positron Collider…
Hadron masses are subject to few MeV corrections arising from QED interactions, almost entirely arising from the electric charge of the valence quarks. The QED effects include both self-energy contributions and interactions between the…
Motivated by the large cross section of $e^+e^-\to \eta J/\psi$ process measured by the BESIII and Belle Collaborations recently, we evaluate this process at $\mathcal{O}(\alpha_s^4)$ accuracy in the framework of nonrelativistic QCD. We…