相关论文: Neutral Pion Electroproduction on the Proton near …

The total cross sections for pionic charge exchange on hydrogen were measured using a transmission technique on thin CH2 and C targets. Data were taken for pi- lab energies from 39 to 247 MeV with total errors of typically 2% over the…

Using a hadronic framework, we derive an explicit expression for photon production from neutral pions in a weak background magnetic field. Our calculation is built on the proton triangle diagram with an effective Yukawa $\pi^0$-proton…

We present a Regge model for pion photoproduction which is basically free of parameters within the framework of the s-channel helicity amplitude. We use coupling constants of all exchanged mesons determined from empirical decay widths or…

We calculate single pion production by neutrinos in the resonance region. We consider both charged and neutral current reactions on free protons and neutrons. We present differential and total cross sections which can be compared with…

Transverse momentum spectra for neutral pions have been measured by the WA98 experiment in sqrt{s_{nn}}=17.3 GeV Pb+Pb collisions at the CERN SPS and by the PHENIX experiment in sqrt{s_{nn}}=130 GeV Au+Au collisions at RHIC. The neutral…

S-wave photoproduction of pion and kaon pairs on hydrogen is studied. Coupled channel final state interactions between different pseudoscalar mesons are included. Effective mass and momentum transfer distributions as well as total cross…

We develop a model for the weak pion production off the nucleon, which besides the Delta pole mechanism (weak excitation of the $\Delta(1232)$ resonance and its subsequent decay into $N\pi$), includes also some background terms required by…

Pion scattering and electro-production amplitudes have been computed in a coupled-channel framework incorporating quasi-bound quark-model states, based on the Cloudy Bag model. All relevant low-lying nucleon resonances in the P33, P11, and…

The electromagnetic polarizabilities of the nucleon are fundamental nucleon-structure observables that characterize its response to external electromagnetic fields. The neutron polarizabilities can be accessed from Compton-scattering data…

We have analysed pion photoproduction imposing constraints from fixed t dispersion relations and unitarity. Coupled integral equations for the S and P wave multipoles were derived from the dispersion relations and solved by the method of…

Photoproduction of neutral pions from nuclei (carbon, calcium, niobium, lead) has been studied for incident photon energies from 200 MeV to 800 MeV with the TAPS detector using the Glasgow photon tagging spectrometer at the Mainz MAMI…

In this review we present the recent advances for calculations of the reactions $NN\to NN\pi$ using chiral effective field theory. Discussed are the next-to-next-to leading order loop contributions with nucleon and Delta-isobar for near…

We carry out a series of studies on pion and photon productions in neutrino/electron/photon--nucleus scatterings. The low energy region is investigated by using a chiral effective field theory for nuclei. The results for the neutral current…

We consider the charge-odd correlations (COC) in cross sections of processes of production of charged particles. The cases of a muonic pair and pion systems $\pi^{+}\pi^{-},\pi^{+}\pi^{-}\pi^{0}$ are considered in detail for electron-proton…

In view of the recent WA98 data of pi0 spectra from central Pb+Pb collisions at the CERN SPS, we analyze the production of neutral pions for A+$ collisions across the periodic table at sqrt(s)=17 AGeV and 200 AGeV within the framework of…

New results are reported from a measurement of $\pi^0$ electroproduction near threshold using the $p(e,e^{\prime} p)\pi^0$ reaction. The experiment was designed to determine precisely the energy dependence of $s-$ and $p-$wave…

A calculation of the pion-production operator up to next-to-next-to-leading order for s-wave pions is performed within chiral effective field theory. In the previous study [Phys. Rev. C 85, 054001 (2012)] we discussed the contribution of…

The first experimental results for coherent $\pi^0$-electroproduction on the deuteron, $e+d\to e+d +\pi^0$, at large momentum transfer, are reported. The experiment was performed at Jefferson Laboratory at an incident electron energy of…

We study the reaction of pion photoproduction on the nucleon in the framework of chiral perturbation theory with explicit $\Delta(1232)$ degrees of freedom. In the covariant approach, we give results up to order $\epsilon^3$ in the small…

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…