Related papers: Pionic transparency in semi-exclusive electroprodu…
The CLAS experiment E02-104, part of the EG2 run at Jefferson Lab, was performed to study the hadronization process using semi inclusive deep inelastic scattering off nuclei. Electron beam energy of 5 GeV and the CLAS large acceptance…
I concentrate in this article on the reaction--coherent pion production by neutrinos incident on nuclei. A special effort is made in order to describe the approximations entering the calculation. I conclude that the reaction is well…
In order to establish links between p-wave pion production in nucleon-nucleon collisions and low energy three-nucleon scattering, an extensive programme of experiments on pion production is currently underway at COSY-ANKE. The final proton…
Regge-pole based descriptions of pion-electroproduction on nucleons have given a very good description of the longitudinal components of the cross sections. However, these very same models grossly underestimate the transverse components. A…
We investigate nuclear transparency induced by pion electroproduction on nuclei, $A(e,e'\pi^+)$, with our interest in the role of the two-step process in the Glauber multiple scattering theory. Based on the framework in which the quantum…
New results for the exclusive and quasi-free cross sections off neutrons bound in deuterium ${\gamma}_vn(p) \rightarrow p{\pi}^{-} (p)$ are presented over a wide final state hadron angle range with a kinematic coverage of the invariant mass…
The nuclear transparency of the charged hadron produced in the inclusive $(e,e^\prime)$ reaction on the nucleus has been calculated using Glauber model for the nuclear reaction. The color transparency (CT) of the produced hadron and the…
We study the near-threshold pion-induced production of $\phi$ mesons off nuclei in the kinematical conditions of the HADES experiment, recently performed at GSI. The calculations have been performed within a collision model based on the…
The pion-production $\pi^+ A \to \pi^+\pi^{\pm} A'$ reactions were studied on nuclei $^{2}H$, $^{12}C$, $^{40}Ca$ and $^{208}Pb$ at a pion energy of $T_{\pi^{+}}$=283 MeV using the CHAOS spectrometer. The experimental results are reduced to…
We have measured the nuclear transparency of the fundamental process $\gamma$ n $\to \pi^-$ p in $^4$He. These measurements were performed at Jefferson Lab in the photon energy range of 1.6 to 4.5 GeV and at $\theta^{\pi}_{cm}= 70^\circ$…
A description of exclusive charged pion electroproduction $(e,e'\pi^{\pm})$ off nucleons at high energies is proposed. The model combines a Regge pole approach with residual effect of nucleon resonances. The exchanges of $\pi$(140), vector…
We study the photoproduction of $\eta^\prime$ mesons from nuclei near the threshold within the collision model based on the nuclear spectral function. The model takes properly into account both primary photon-nucleon and secondary…
The STAR Collaboration reports on the photoproduction of $\pi^+\pi^-$ pairs in gold-gold collisions at a center-of-mass energy of 200 GeV/nucleon-pair. These pion pairs are produced when a nearly-real photon emitted by one ion scatters from…
The dynamics of nuclear transparency in hard nuclear reactions is studied by an expansion of the correlator of the hard scattering operator on a hadronic basis. Colour transparency appears as an effect of interference between the amplitudes…
A model for the pionic components of nuclear wave functions is obtained from light front dynamical calculations of binding energies and densities. The pionic effects are small enough to be consistent with measured nuclear di-muon production…
The exclusive reaction $\gamma p \to p \pi^+ \pi^-$ was studied in the photon energy range 3.0 - 3.8 GeV and momentum transfer range $0.4<-t<1.0$ GeV$^2$. Data were collected with the CLAS detector at the Thomas Jefferson National…
Photonuclear reactions are induced by the strong electromagnetic field generated by ultrarelativistic heavy-ion collisions. These processes have been extensively studied in ultraperipheral collisions, where the impact parameter is larger…
The neutral pion photoproduction on the proton near threshold has a very small scattering cross section when compared to the charged channels, which in ChPT is explained by strong cancellations between the lowest order pieces. Therefore it…
Recent results for the photoproduction of mesons off nuclei are reviewed. These experiments have been performed for two major lines of research related to the properties of the strong interaction. The investigation of nucleon resonances…
Dielectron production in the $\pi N$ interaction at not large energies is studied. The dominant contribution of the $\Delta$-isobar creation in the intermediate state at incident pion momenta of about 0.3-0.4 GeV$/$c is shown. The…