Related papers: Compton Scattering by the Proton using a Large-Acc…
The electric alpha and magnetic beta pion Compton polarizabilities characterize the pion's deformation in the electromagnetic field of the gamma during gamma-pi Compton scattering. The pion polarizabilities are key observables, and provide…
The COMPASS collaboration at CERN has investigated pion Compton scattering, $\pi^-\gamma\rightarrow \pi^-\gamma$, at centre-of-mass energy below 3.5 pion masses. The process is embedded in the reaction…
As a guideline for future experiments to extract the four (leading) spin polarizabilities of the nucleon, we have constructed the forward amplitude for polarized Compton scattering by dispersion integrals. These integrals have been…
Double-polarization observables in the reaction $\vec{e}p \rightarrow e'\vec{p'}\gamma{}$ have been measured at $Q^2=0.33 (GeV/c)^2$. The experiment was performed at the spectrometer setup of the A1 Collaboration using the 855 MeV polarized…
We calculate the amplitude T_1 for forward doubly-virtual Compton scattering in heavy-baryon chiral perturbation theory, to fourth order in the chiral expansion and with the leading contribution of the gammaNDelta form factor. This provides…
Photons preferentially Compton scatter perpendicular to the plane of polarisation. This property can be exploited to design instruments to measure the linear polarisation of hard X-rays ($\sim$10 - 100 keV). Photons may undergo two…
The contribution of the box and crossed two-pion-exchange diagrams to proton-proton scattering at 90$^{\circ}_{c.m.}$ is calculated in the laboratory momentum range up to 12 GeV/c. Relativistic form factors related to the nucleon and pion…
The mean square polarizability radii of the proton have been measured for the first time in a virtual Compton scattering experiment performed at the MIT-Bates out-of-plane scattering facility. Response functions and polarizabilities…
The electric ${\alpha}_{\pi}$ and magnetic $\beta_{\pi}$ charged pion Compton polarizabilities are of fundamental interest in the low-energy sector of quantum chromodynamics (QCD).They are directly linked to the phenomenon of spontaneously…
Polarization characteristics of the gamma beam obtained by the Compton back scattering of laser photons on high energy electrons are evaluated by Monte-Carlo simulations. It is assumed that outgoing photons are tagged; the energy dispersion…
The polarizabilities of light pseudoscalar mesons can be extracted from differential cross sections for Compton scattering near threshold. While this has been accomplished for charged pions employing Primakoff reactions, a corresponding…
A new partial wave analysis of pion photoproduction has been obtained in the framework of fixed-t dispersion relations valid form threshold up to 500 MeV. It is based on new Mainz data for \pi^{0} and \pi^{+} production off the proton and…
A microscopic coupled-channels model for Compton and pion scattering off the nucleon is introduced which is applicable at the lowest energies (polarizabilities) as well as at GeV energies. To introduce the model first the conventional…
Virtual Compton Scattering is studied at the Thomas Jefferson National Accelerator Facility in the energy domain below pion threshold and in the Delta(1232) resonance region. The data analysis is based on the Dispersion Relation (DR)…
New precise results of a measurement of the elastic electron-proton scattering cross section performed at the Mainz Microtron MAMI are presented. About 1400 cross sections were measured with negative four-momentum transfers squared up to…
We calculated two--photon exchange effects for elastic electron--proton scattering at high momentum transfers. The corresponding nucleon Compton amplitude is defined by two space--like virtual photons that appear to have significant…
We update the predictions of the SU(2) baryon chiral perturbation theory for the dipole polarisabilities of the proton, $\{\alpha_{E1},\,\beta_{M1}\}_p=\{11.2(0.7),\,3.9(0.7)\}\times10^{-4}$fm$^3$, and obtain the corresponding predictions…
A measurement of the electroproduction of photons off protons in the deeply inelastic regime was performed at Jefferson Lab using a nearly 6-GeV electron beam, a longitudinally polarized proton target and the CEBAF Large Acceptance…
We study two-photon contribution to the elastic lepton-proton scattering, associated with sigma meson exchange, with special attention paid to the low-Q2 region. We show that the corresponding amplitude grows sharply but remains finite at…
In the scaling regime, amplitudes for backward virtual Compton scattering and hadron annihilation into two photons depend on structure functions that describe the hadron-photon transition at the partonic level. We construct simple…