Related papers: Probing Positron Gravitation at HERA
An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Gravity dependence on rotation or spin direction is experimentally constrained for non-relativistic…
A measurement is presented of elastic deeply virtual Compton scattering \gamma* p \to \gamma p made using e^+ p collision data corresponding to a luminosity of 46.5 pb^{-1}, taken with the H1 detector at HERA. The cross section is measured…
Recent results from searches for physics beyond the Standard Model (SM) in electron/positron-proton collisions at HERA at center-of-mass energies of 300 and 320 GeV are presented. They were performed on a data sample collected in the period…
The deflection of gamma-rays in Earth's gravitational field is tested in laser Compton scattering at high energy accelerators. Within a formalism connecting the bending angle to the photon's momentum it follows that detected gamma-ray…
Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and…
A measurement of elastic deeply virtual Compton scattering gamma* p -> gamma p using e^+ p and e^- p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 306…
A measurement is presented of elastic Deeply Virtual Compton Scattering e^+ + p -> e^+ + photon + p at HERA using data taken with the H1 detector. The cross section is measured as a function of the photon virtuality, Q^2, and the invariant…
Photon-proton ($\gamma p$) interactions with~$Q^2<10^{-2}$~GeV$^2$ and deep-inelastic scattering ($\gamma^* p$) interactions with photon virtualities $Q^2>5$~GeV$^2$ are studied at the high energy electron-proton collider HERA. The…
Consideration of antigravity for antiparticles is an attractive target for various experimental projects. There are a number of theoretical arguments against it but it is not quite clear what kind of experimental data and theoretical…
Measurements of Deep-Inelastic Neutral and Charged current interactions are presented in lepton proton scattering at HERA. The measurements are obtained from taken during 1996 to 1999 and consists of $30 \rm{pb^{-1}}$ of $e^+p$ and $16…
Neutral-current (NC) and charged-current (CC) deep inelastic scattering (DIS) interactions have been studied in electron-proton and positron-proton collisions with longitudinally polarised lepton beams using the H1 and ZEUS detectors at…
The H1 and ZEUS collaborations at HERA have searched for signatures of physics beyond the Standard Model using high Q^2 neutral current deep inelastic electron-proton and positron-proton scattering events. No significant deviations from…
Deep-inelastic positron-proton scattering events at low photon virtuality Q^2 with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional…
The $e^{+}p$ and $e^{-}p$ scattering data recorded at HERA during the recent years offer the possibility to study electroweak effects in $ep$ interactions apparent at high momentum transfers, $Q^{2}$, and to reveal information on the proton…
HERA is the only high energy electron-proton collider in the world today and hence has unique opportunities both to probe the structure of the proton and to search for physics beyond the Standard Model. Results are presented for…
Deeply virtual Compton scattering has been measured in e^+p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb^-1. Cross sections are presented as a function of the photon virtuality, Q^2, and photon-proton…
The H1 and ZEUS collaborations at HERA have searched for signatures of physics beyond the Standard Model with high Q^2 neutral current deep inelastic electron-proton and positron-proton scattering events. No significant deviations from…
Two results in ep physics using HERA data are discussed: a measurement of the effective transverse parton momentum in the proton by studying the production of prompt-photons in photoproduction events in the ZEUS collaboration and…
The beam-helicity asymmetry in exclusive electroproduction of real photons by the longitudinally polarized HERA positron beam scattering off an unpolarized hydrogen target is measured at HERMES. The asymmetry arises from deeply virtual…
The first observation of an azimuthal cross--section asymmetry with respect to the charge of the incoming lepton beam is reported from a study of hard exclusive electroproduction of real photons. The data have been accumulated by the HERMES…