Related papers: Protonium: Discovery and Prediction

Based on the data samples collected at the energies of $J/\psi$, $\psi(3686)$, $\psi(3770)$ and $\psi(4040)$ resonances with the BESIII detector at the BEPCII storage ring, we present charmonium decays in two aspects. One is the search for…

In the quark model, hadrons are dominantly bound states of quark-antiquark pairs (mesons) or three quarks (baryons), but QCD also allows hadronic states to be composed of more quarks bound together. Recently, BESIII, Belle and LHCb have…

A first search for the $\it{\Xi}_{bc}^{+}\to J/\it{\psi}\it{\Xi}_{c}^{+}$ decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of $9\,\mathrm{fb}^{-1}$ recorded…

Nonstrange baryonium spectrum is systematically studied by using the Gaussian expansion method in a flux tube model with the six-body confinement potential. All the model parameters are fixed by baryon properties, so the baryonium…

BES Collaboration has collected 58 million $J/\psi$ events at the Beijing Electron-Positron Collider (BEPC). $J/\psi$ decays provide an excellent place for studying excited nucleons and hyperons -- $N^*$, $\Lambda^*$, $\Sigma^*$ and $\Xi^*$…

The Positronium (Ps) system, a bound state of an electron and a positron, is suitable for testing the predictions of quantum electrodynamics (QED), since its properties can be perturbatively calculated to high accuracy and, unlike the…

Charmonium spectroscopy provides strong guidelines to effective field theories, thereby gaining insight into quark confinement and the generation of hadron masses. Hadronic transitions between charmonium states have been measured with…

The baryonic decays of $J/ \psi$ provide a new way to study the internal structure of baryons. A simple diquark model applied to the calculation of the $\bar{B}B$ decay cross-sections is compared with the ordinary constituent quark model.…

We propose that the broad $1^{--}$ resonance structure recently discovered by BES in $J/\psi\to K^{+}K^{-}\pi^{0}$ is the P-wave excitation of a diquark-antidiquark bound state. This interpretation implies that there exists a negative…

The production of pions by antiproton-deuteron annihilation at rest is analyzed. Assuming the possible existence of two delta-isobars in a deuteron some enhancement in the distribution over the invariant mass of two negative charged pions…

Using data collected with the BESIII detector operating at the Beijing Electron Positron Collider at center-of-mass energies of $\sqrt{s}=4.23$, 4.26, and 4.36~GeV, we observe $\EE\to \pphc$ for the first time. The Born cross sections are…

In a model in which leptons, quarks, and the recently introduced hyperquarks are built up from two fundamental spin 1/2 preons, the standard model weak gauge bosons emerge as preon bound states. In addition, the model predicts a host of new…

A search for a new boson X is presented using CERN LHC proton-proton collision data collected by the CMS experiment at $\sqrt{s}$ = 13 TeV in 2016-2018, and corresponding to an integrated luminosity of 138 fb$^{-1}$. The resonance X decays…

We study the sensitivity of past and future stopped-pion experiments to light, invisible dark sector particles produced in exotic pion decays. We consider two-body decays involving sterile neutrinos, $\pi^+ \to \ell^+ N$, as well as…

BESIII is a new state-of-the-art 4pi detector at the recently upgraded BEPCII two-ring e+e- collider at the Institute of High Energy Physics in Beijing. It has been in operation for three years, during which time it has collected the…

The BESIII Collaboration recently reported the observation of two new resonances, $X(1910)$ and $X(2300)$, which have sparked our interest in studying the light hadron family with $J^{PC}=1^{+-}$ . In this work, we investigate the mass…

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…

Bosonic bunching is a term used to describe the well-known tendency of bosons to bunch together, and which differentiates their behaviour from that of fermions or classical particles. However, in some situations perfectly indistinguishable…

Two structures are observed close to the kinematic threshold in the $\Xi_b^0 \pi^-$ mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb$^{-1}$ recorded by the LHCb experiment. In…

The first observation of the heavy baryonic state \Xi_b^0 is reported by the CDF Collaboration. A new decay mode of the established state \Xi_b^- is also observed. In both cases the decay into a \Xi_c plus a charged pion is seen, with an…