Related papers: Meson resonances in forward-angle $\pi^+\pi^-$ pho…
Central exclusive and semiexclusive production of $\pi^+\pi^-$ pairs is measured with the CMS detector in proton-proton collisions at the LHC at center-of-mass energies of 5.02 and 13 TeV. The theoretical description of these…
Pion induced reactions provide unique opportunities for an unambiguous description of baryonic resonances and their coupling channels by means of a partial wave analysis. Using the secondary pion beam at SIS18, the two pion production in…
Electromagnetic radiation from excited hadronic matter is one of the best ways to study the properties of the matter. Considering various processes in the hadronic gas, Kapusta et al \cite{Kapusta_photons} have found a $\pi\rho \rightarrow…
Total cross sections, angular distributions, and invariant-mass distributions have been measured for the photoproduction of $\pi^0\pi^0$ pairs off free protons and off nucleons bound in the deuteron. The experiments were performed at the…
In this contribution I discuss prospects for photoproducing hybrid mesons at CEBAF, based on recent model results and experimental indications of possible hybrids. One excellent opportunity appears to be a search for the I=1, JPC=2+-,…
We report on a high statistics measurement of the cross section of the process gamma gamma to pi^+ pi^- in the center-of-mass energy range 0.8 GeV/c^2 < W < 1.5 GeV/c^2 with 85.9 fb^-1 of data collected at sqrt(s)=10.58 GeV and 10.52 GeV…
Within the framework of non-local quark model of Nambu--Jona-Lasinio type the two-photon decay of radial excited state of $\pi_0$-meson -- $\pi_0'$ -- is found to be $3.6\KeV$. The radial excitation of pion is described with the use of…
Within the framework of the relativistic Vlasov-Uehling-Uhlenbeck transport model based on the relativistic nonlinear NL$\rho$ interaction, we study pion in-medium effects on the $\pi^-/\pi^+$ ratio in Au+Au collisions at the energy of…
The photoproduction of pi0pi0 and pi0pi+/- pairs off 40Ca has been investigated with the TAPS detector using the Glasgow photon tagging spectrometer at the Mainz MAMI accelerator. Data have been taken for incident photon energies in the…
Production of resonances is considered in the framework of the single-freeze-out model of ultra-relativistic heavy ion collisions. The formalism involves the virial expansion, where the probability to form a resonance in a two-body channel…
Deeply virtual electroproduction of pion in exclusive reaction $p(e,e'\pi^+)n$ is studied using a two-component model which includes soft hadronic and hard partonic reaction mechanisms. The results are compared with the experimental data…
Exclusive photoproduction cross sections have been measured for the process $\gamma p \rightarrow p\pi^0(e^+e^-(\gamma))$ with the Dalitz decay final state using tagged photon energies in the range of $E_{\gamma} = 1.275-5.425$ GeV. The…
Within the framework of dispersion theory, we study the the processes $e^+e^-\to \phi(2170) \to \phi \pi\pi(K\bar{K})$. The strong pion-pion final-state interactions, especially the $K\bar{K}$ coupled channel in the $S$-wave, are taken into…
A partial wave analysis of pion photoproduction has been obtained in the framework of fixed-t dispersion relations valid from threshold up to 500 MeV. In the resonance region we have precisely determined the electromagnetic properties of…
We study the scaling regime of pion electroproduction in the backward region, eN->e'N'pi. We compute the leading-twist amplitude in the kinematical region, where it factorises into a short-distance matrix element and long-distance dominated…
We report a measurement of the exclusive production of pairs of charged pions in proton-proton collisions, dominated by the process $pp \rightarrow p^{(*)} \pi^{+}\pi^{-} p^{(*)}$, where $\rm p^{(*)}$ stands for a diffractively dissociated…
We present a method to calculate pion electro-production amplitudes in a coupled-channel framework incorporating quasi-bound quark-model states. The method offers a clear prescription how to extract the resonant part of the amplitudes, even…
Exclusive electroproduction of pi0 mesons on protons in the backward hemisphere has been studied at Q**2 = 1.0 GeV**2 by detecting protons in the forward direction in coincidence with scattered electrons from the 4 GeV electron beam in…
We use general relations between the Transition Distribution Amplitudes (TDAs), entering the description of the p -> pi0 transition, and the proton Distribution Amplitudes (DAs) in the soft-pion limit to estimate the size of the amplitude…
Pion transition form factor for the process $\gamma*\gamma*\to \pi^0$ at space-like values of photon momenta is calculated within the effective quark-meson model with the interaction induced by instanton exchange. The leading and…