Related papers: ep Physics at High Q-squared
A brief review is given on the physics potential of HERA beyond the presently approved programme. Questions of particular interest include QCD in a regime of weak coupling and high partonic densities achieved in eA collisions and spin…
High energy scattering processes of charged particles are accompanied by radiation of hard photons. Emission collinear to the incident particles, which leads to a reduction of the effective beam energy, and the possibility to directly…
New QCD results obtained by the H1 Collaboration are summarized. These results are based on data taken in $e^{\pm}p$ collisions at HERA I (1994-2002) and HERA II (2003-2007) corresponding to an integrated luminosity of almost $\rm 0.5…
The high energy program of the HERA $ep$ collider ended in March 2007, where data equivalent to an integrated luminosity of $\sim$ 0.5 fb$^{-1}$ has been collected by the H1 experiment. In this context, some of the most recent results from…
Starting in 2008 the H1 and ZEUS experiments have been combining their data in order to provide the most complete and accurate set of deep-inelastic data as the legacy of HERA. The present review presents these combinations, both published…
All experimental measurements of particle physics today are beautifully described by the Standard Model. However, there are good reasons to believe that new physics may be just around the corner at the TeV energy scale. This energy range is…
Recent experimental results of searches for new phenomena performed at high energy colliders are reviewed. The results reported are based on data samples of up to 1 fb^-1 and 4 fb^-1 collected at HERA and at the Tevatron, respectively. No…
Events with a final-state proton carrying a large fraction of the proton-beam momentum, x_L>0.6, and the square of the transverse momentum p_T^2 <0.5 GeV^2, have been studied in e^+p collisions with the ZEUS detector at HERA. Data with…
A large number of measurements with polarized beams and/or spin analysis of final state particles has been performed at the e^+e^- colliders LEP and SLC, providing important information on the dynamics of high energy interactions. In this…
The study of photoproduction reactions has gained a unique opportunity with the HERA data. The high center of mass energy allows to carry out quantitative tests of QCD, to explore the substructure of both the photon and the proton and to…
Data on the hadronic final state of deep-inelastic events at the ep collider HERA are reviewed. Fragmentation properties in the current region extracted from charged particle spectra are compared to e+e- and fixed target experiments at…
In a search for signatures of physics processes beyond the Standard Model, various eeqq vector contact-interaction hypotheses have been tested using the high-Q^2, deep inelastic neutral-current e^+p scattering data collected with the ZEUS…
The diffractive process ep \rightarrow eXY, where Y denotes a proton or its low mass excitation with MY < 1.6 GeV, is studied with the H1 experiment at HERA. The analysis is restricted to the phase space region of the photon virtuality 3…
We study photoproduction reactions in a polarized ep collider mode of HERA at sqrt(s)=298 GeV. We examine the sensitivity of the cross sections and their asymmetries to the proton's polarized gluon distribution and to the completely unknown…
A model-independent search for deviations from the Standard Model prediction is performed in $e^+ p$ and $e^- p$ collisions at HERA II using all high energy data recorded by the H1 experiment. This corresponds to a total integrated…
The radiation pattern within high energy quark- and gluon-initiated jets (jet substructure) is used extensively as a precision probe of the strong force as well as an environment for optimizing event generators with numerous applications in…
HERA, the electron-proton collider, enables to probe the proton with a high resolving power due to the deep inelastic scattering reactions at high $Q^2$ values. In the low $Q^2$ region, one can study the properties of the photon. The large…
Data from the HERA collider experiments, H1 and ZEUS, have been fundamental to the rapid recent development of our understanding of the partonic composition of the proton and of QCD. This report focuses on inclusive measurements of neutral…
A model-independent search for deviations from the Standard Model prediction has been performed in e+p and e-p collisions at HERA using H1 data. All experimentally measurable event topologies involving isolated electrons, photons, muons,…
We have considered the physics opportunities of future lepton-hadron colliders and how these opportunities might be realized in a possible polarized eRHIC facility and an e-p collider as part of a staged or final version VLHC. We evaluated…