Related papers: The process $e^+e^- \to \pi \pi X(3823)$ in the so…
Properties of Regge trajectories for charmonium are studied. Possible interpretations and their implications to newly observed X(3872) are examined. It is found that the mass of X(3872) is consistent with the 1^{++} 2^3P_1 and the 2^{-+}…
It is argued that the charged $Z^+_c(3885)$ resonance, treated as a `molecular' state of charmed $D$ and $D^*$ mesons, is likely to consist of two peaks unequally coupled to the $D^{*+} \bar D^0$ and $D^+ \bar D^{*0}$ channels. The peaks…
We study the processes e+ e- --> 3(pi+pi-)gamma, 2(pi+pi-pi0)gamma and K+ K- 2(pi+pi-)gamma, with the photon radiated from the initial state. About 20,000, 33,000 and 4,000 fully reconstructed events, respectively, have been selected from…
The process $e^{+}e^{-} \to \phi \eta^{\prime}$ has been studied for the first time in detail using data sample collected with the BESIII detector at the BEPCII collider at center of mass energies from 2.05 to 3.08 GeV. A resonance with…
In arxiv: 2102.05575 a two-step process $pn \to (pp) \pi^- \to (\Delta N) \pi^- \to (d \pi^+) \pi^-$ was calculated by using experimental total cross sections for the single-pion production processes $pn \to pp \pi^-(I=0)$ and $pp \to d…
We present a study of the process $e^{+}e^{-}\to\eta\phi$ using data samples collected with the BESIII detector corresponding to an integrated luminosity of 15.03 fb$^{-1}$ at 23 center-of-mass energies from 3.773 to 4.600 GeV. The Born…
Light, beyond-the-standard-model particles $X$ in the 1-100 MeV mass range can be produced in nuclear and hadronic reactions but would have to decay electromagnetically. We show that simple and well-understood low-energy hadronic processes…
We report recent results on the properties of the X(3872) produced via the B+ --> K+ X(3872) decay process. We observe X -->pi+pi-pi0 J/psi decays where the 3pi invariant masses cluster near the upper kinematic boundary suggesting that they…
Direct, resonant production of the charmonium states $\chi_{c1}$ and $\chi_{c2}$ in electron-positron annihilation is investigated. Depending on details of the model, a sizeable variation of the prediction for the production cross section…
Recently, the BaBar Collaboration reported a broad resonance structure near 2 GeV when analyzing the $e^+e^-\to f_1(1285)\pi^+\pi^-$ process, which provides a good opportunity to study the higher $\rho$-mesonic states. When considering the…
We argue that relatively compact charmonium states, $J/\psi$, $\psi(2S)$, $\chi_c$, can very likely be bound inside light hadronic matter, in particular inside higher resonances made from light quarks and/or gluons. The charmonium state in…
Based on a QED Lagrangian with additional photon-photon coupling an explicit bound state description is presented, attempting a physical correct and parameter free description of free particles. Applied to p-e- and e+-e- systems, with a…
We present a quark model calculation of the charmonium spectrum with self energy corrections due to the coupling to the meson-meson continuum. The bare masses used in the calculation are computed within the relativized quark model by…
We study the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-\gamma$, with a hard photon radiated from the initial state. About 60,000 fully reconstructed events have been selected from 89 $fb^{-1}$ of BaBar data. The invariant mass of the hadronic…
The cross section of the process $e^+e^-\to \pi^+\pi^-\pi^0$ was measured in the Spherical Neutral Detector experiment at the VEPP-2M collider in the energy region $\sqrt[]{s} = 980 \div 1380$ MeV. The measured cross section, together with…
The process e+e- --> pi+ pi- pi0 gamma has been studied at a center-of-mass energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum we have…
New enhancements in the charmonium and bottomonium spectra observed since 2003 are very briefly reviewed. Special attention is paid to $\chi_{c1}(3872)$ (formerly $X(3872)$) owing to its remarkable proximity to the $\bar{D}^{\star0}\!D^0$…
The spectral function of the charged pion form factor was extracted from two data sets. The difference between the two sets is based on the presence or absence of the recent measurement of the $\pi^+ \pi^-$ production by CMD3. Although the…
Pion elastic, charge exchange scattering and induced eta production on the trinucleon systems are investigated in a coupled-channels approach in momentum space with Fadeev wave functions. The channel $\pi N \rightarrow \eta N$ is included…
We calculate the E1 transition widths of higher vector charmonium states into the spin-triplet 2P states in three typical potential models, and discuss the possibility to detect these 2P states via these E1 transitions. We attempt to…