Related papers: The OLYMPUS Experiment
We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer by using a quark-parton representation of virtual Compton scattering. We thus can relate the two-photon exchange amplitude to…
Differential cross sections for elastic scattering of photons from the deuteron have recently been measured at the Tagged-Photon Facility at the MAX IV Laboratory in Lund, Sweden. These first new measurements in more than a decade further…
The PP2PP experiment is devoted to the proton-proton elastic scattering measurement at the Relativistic Heavy Ion Collider at the centre-of-mass energies between 50 and 500 GeV and the four-momentum transfer $0.0004 \leq |t| \leq 1.3$…
Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at {\surd}s = 7 TeV in dedicated runs with the Roman Pot detectors placed as close as seven times the transverse beam size (sbeam)…
We evaluate the two-photon exchange correction to the elastic electron-proton scattering cross section within a dispersive framework. Besides the elastic contribution, we account for all $\pi N$ intermediate state contributions using the…
We extract two-photon exchange amplitudes for the elastic electron-proton scattering at Q^2=2.5 GeV^2 from the unpolarized cross-section and recent polarization transfer measurements. There are three independent amplitudes, but only one of…
We review recent theoretical and experimental progress on the role of two-photon exchange (TPE) in electron-proton scattering at low to moderate momentum transfers. We make a detailed comparison and analysis of the results of competing…
Using the available cross section and polarization data for elastic electron-proton scattering, we provide an extraction of the two-photon exchange amplitudes at a common value of four-momentum transfer, around Q^2 = 2.5 GeV^2. This…
A precise comparison of the cross sections for the elastic scattering of electrons and positrons on protons was performed recently at the VEPP-3 storage ring in Novosibirsk, Russia. To provide the proposed accuracy, the energies of the…
The TOTEM Experiment is designed to measure the total proton-proton cross-section with the luminosity-independent method and to study elastic and diffractive pp scattering at the LHC. To achieve optimum forward coverage for charged…
A proposal is made by the University College of London Group [1] for measuring the target-ionization cross sections in Ps and atom scattering. We calculate the corresponding theoretical data for Ps-H and Ps-He systems including the effect…
We evaluate the two-photon exchange correction to the unpolarized cross section in the elastic muon-proton scattering within dispersion relations. One of the six independent invariant amplitudes requires a subtraction. We fix the…
A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision…
The analyzing powers in proton-deuteron elastic and proton-neutron quasi-elastic scattering have been measured at small angles using a polarized proton beam at the COSY storage ring incident on an unpolarized deuterium target. The data were…
We present an improved evaluation of the two-photon exchange correction to the unpolarized lepton-proton elastic scattering process at very low-energies relevant to the MUSE experiment, where only the dominant intermediate elastic proton is…
In 2018, a test run with muons in the North Area at CERN was performed, running parasitically downstream of the COMPASS spectrometer. The aim of the test was to investigate the elastic interactions of muons on atomic electrons, in an…
Two-photon exchange contributions to elastic electron-scattering are reviewed. The apparent discrepancy in the extraction of elastic nucleon form factors between unpolarized Rosenbluth and polarization transfer experiments is discussed, as…
There is a significant discrepancy between the values of the proton electric form factor, $G_E^p$, extracted using unpolarized and polarized electron scattering. Calculations predict that small two-photon exchange (TPE) contributions can…
The proton elastic form factor ratio can be measured either via Rosenbluth separation in an experiment with unpolarized beam and target, or via the use of polarization degrees of freedom. However, data produced by these two approaches show…
We report on a measurement of the asymmetry in the scattering of transversely polarized electrons off unpolarized protons, A$_\perp$, at two Q$^2$ values of \qsquaredaveragedlow (GeV/c)$^2$ and \qsquaredaveragedhighII (GeV/c)$^2$ and a…