相关论文: $J/\psi \to \gamma\eta'\pi^+\pi^-$ and the structu…

In this paper, we study the structure around the $p\bar{p}$ threshold that appears in $\eta'\pi^+\pi^-$, $3(\pi^+\pi^-)$ and $K_S^0K_S^0\eta$ invariant mass spectra in the processes of relevant $J/\psi$ radiative decays. The $N\bar{N}$…

We analyze the origin of the structures observed in the reactions $e^+e^-\to 3(\pi^+\pi^-)$, $2(\pi^+\pi^-\pi^0)$, $\omega\pi^+\pi^-\pi^0$, and $e^+e^-\to 2(\pi^+\pi^-)\pi^0$ around the antiproton-proton ($\bar pp$) threshold. We calculate…

A systematic analysis of the near-threshold enhancement in the $\bar pp$ invariant mass spectrum seen in the decay reactions $J/\psi \to x \bar pp$ and $\psi (3686) \to x \bar pp$ $(x = \gamma,\, \omega,\, \rho,\, \pi,\, \eta)$ is…

Using $1.09\times10^{9}$ $J/\psi$ events collected by the BESIII experiment in 2012, we study the $J/\psi\rightarrow\gamma\eta^{\prime}\pi^{+}\pi^{-}$ process and observe a significant abrupt change in the slope of the…

We study the $J/\psi \to \gamma \pi^+ \pi^-$, $\gamma \pi^0 \eta$ reactions from the perspective that they come from the $J/\psi \to \phi(\omega) \pi^+ \pi^-, \rho^0\pi^0 \eta$ reactions, where the $\rho^0$, $\omega$, and $\phi$ get…

We present a measurement of the cross section of the process $e^+e^-\to\pi^+pi^-\psi(2S)$ from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the PEP-II $e^+e^-$ storage rings. The…

The $pp \to pp\gamma\gamma$ reaction has been measured at CELSIUS using the WASA $4\pi$-detector with hydrogen pellet target. At $T_p = 1.20$ and 1.36 GeV, where most of the statistics has been accumulated, the $\gamma\gamma$ invariant mass…

A reaction model for $\gamma + p \to J/\psi + p$ photoproduction, which exposes the $c \bar c$ content of the photon in making the transition $\gamma\to c\bar c + \mathbb P \to J/\psi$ and couples the intermediate $c \bar c$ system to the…

We show that the resonance-like structure found by the \emph{CELSIUS-WASA Collaboration} in the two-photon invariant mass spectrum of the reaction $pp \to pp \gamma \gamma$ is rather a signature of the $NN$-decoupled dibaryon resonance…

The near-threshold enhancement in the ppbar invariant mass spectrum from the B^+ -> K^+ ppbar decay reported recently by the BaBar Collaboration is studied within the J\"ulich NNbar model. We illustrate that the invariant mass dependence of…

In this study, we analyze the first measurement of the electron-positron invariant mass spectrum in $J/\psi \to \pi^0 e^+e^-$ by BESIII, using the framework of resonance chiral theory. Our results indicate that both strong interaction and…

We evaluate the threshold matrix-element for the reaction $pp \to pp\pi^0$ in a fully relativistic Feynman diagrammatic approach. We employ a simple effective range approximation to take care of the S-wave $pp$ final-state interaction. The…

The measurement by the BES collaboration of J/psi -> gamma p pbar decays indicates an enhancement at the p-pbar threshold. In another experiment BES finds a peak in the invariant mass of pi-mesons produced in the possibly related decay…

We investigate the nature of the near-threshold enhancement in the ppbar invariant mass spectrum of the reaction J/Psi -> gamma ppbar reported recently by the BES Collaboration. Using the Juelich NNbar model we show that the mass dependence…

We investigate the lineshape of the $e^{+}e^{-}\to J/\psi\,\pi^{+}\pi^{-}$ cross section in the vicinity of the $D^{*}\bar{D}+c.c.$ threshold, where the ``so-called" $G(3900)$ is observed in the $e^+e^-\to D\bar{D}$ channel. To take into…

We calculate the cross section for the $\gamma \gamma \to J/\psi J/\psi$ process. Two mechanisms are considered: box (two-loop) diagrams of the order of $O(\alpha_{em}^2 \alpha_s^2)$ and two-gluon exchange of the order of $O(\alpha_{em}^2…

We suggest that the $\gamma p \to \phi \eta p$ reaction cross section, in the kinematics where the $\eta p$ invariant mass in the final state lies between the threshold value (m$_p$+m$_\eta$) and the N*(1535) resonance mass, is largely…

Using $(10.087\pm0.044)\times10^9$ $J/\psi$ events collected with the BESIII detector at the $e^+e^-$ BEPCII collider, we present the first amplitude analysis of $J/\psi\to\gamma p\bar{p}$ with the $p\bar p$ invariant mass in the $\eta_c$…

Using proton-proton collision data at centre-of-mass energies of $\sqrt{s} = 7$, $8$ and $13\mathrm{\,TeV}$ recorded by the LHCb experiment at the Large Hadron Collider, corresponding to an integrated luminosity of $9\mathrm{\,fb}^{-1}$,…

The reaction $\gamma p \rightarrow p \pi^0 \eta$ has been studied with the CBELSA/TAPS detector at the electron stretcher accelerator ELSA in Bonn for incident photon energies from threshold up to 3.1 GeV. This paper has been motivated by…