Dynamical coupled channel calculation of pion and omega meson production

A dynamical coupled channel approach is used to study $\pi$ and $\omega$--meson production induced by pions and photons scattering from the proton. Six intermediate channels including $\pi N$, $\eta N$, $\pi\Delta$, $\sigma N$, $\rho N$ and $\omega N$ are employed to describe unpolarized and polarized data. Bare parameters in an effective hadronic Lagrangian are determined in a fit to data for $\pi N \to \pi N$, $\gamma N \to \pi N$, $\pi^- p \to \omega n$, and $\gamma p \to \omega p$ reactions at center-of-mass energies from threshold to $W < 2.0$ GeV. The $T$ matrix determined in these fits is used to calculate the photon beam asymmetry for $\omega$-meson production and the $\omega N \to\omega N$ total cross section and $\omega N$ scattering lengths.Comment: 26 pages, 18 figures, submitted to Phys. Rev. C; corrected typos, added references, minor revisions, same results/fig

Angular distribution of X-ray radiation by 500 MeV electrons in an tungsten

Abstract X-rays generated by a 500 MeV electron beam of the Tomsk synchrotron in a tungsten single crystal with a mosaic factor less than 80 00 has been studied theoretically and experimentally. The tungsten crystal was a block with sizes 1:7 Â 10 Â 15 mm 3 aligned with the (1 1 1) plane at the Bragg angle h B % 45°to the electron beam axis. The emitted photons were detected at an angle of 2h B with respect to the electron beam. The emitted angular distributions for the (2 2 2) and (4 4 4) orders have been measured and compared with predictions of the developed theoretical model. This model takes the contribution of parametric X-radiation (PXR) and diffracted transition radiation (DTR) generated by relativistic electrons from in-surface of a crystalline target as well as an influence of an interference between PXR and DTR emission mechanisms into account. The obtained results show the important contribution of DTR to the measured emission yield

Observation of bright monochromatic x rays generated by relativistic electrons passing through a multilayer mirror

yesWe have observed the emission of 15 keV x rays produced by 500 MeV electrons passing through a x-ray multilayer mirrorBelgorod State Universit

X-rays from relativistic electrons crossing a multilayer nanostructure

yesThe results of theoretical and experimental studies of X-ray emission from relativistic electrons crossing periodic nanostructures are presented in this work. Simple formulae describing the characteristics of the total emission from either thin-non-absorbing or thick-absorbing multilayers are derived, accounting for both diffracted-transition and parametric- radiation mechanismsBelgorod State Universit

Observation of bright monochromatic x rays generated by relativistic electrons passing through a multilayer mirror

We have observed the emission of 15 keV x rays produced by 500 MeV electrons passing through a x-ray multilayer mirroryesBelgorod State Universit

X-rays from relativistic electrons crossing a multilayer nanostructure

The results of theoretical and experimental studies of X-ray emission from relativistic electrons crossing periodic nanostructures are presented in this work. Simple formulae describing the characteristics of the total emission from either thin-non-absorbing or thick-absorbing multilayers are derived, accounting for both diffracted-transition and parametric- radiation mechanismsyesBelgorod State Universit

Parametric x radiation from thick crystals

The parametric x radiation from thick Si single crystals with 0.5–5 mm thickness was investigated at an electron energy of 900 MeV. As the crystal thickness increased, both intensity and angular spread reached a plateau after their increase in the thin crystal region, resulting in more brilliant x rays than Feranchuk and Ivashin's prediction [J. Phys. (Paris) 46, 1981 (1985)] for thick crystals. This behavior is consistent with the incoherent model proposed in our previous paper [Phys. Rev. Lett. 70, 3247 (1993)]