Related papers: HERA Collider Physics
Events with at least two high transverse momentum leptons (electrons or muons) are studied using the H1 and ZEUS detectors at HERA with an integrated luminosity of 0.94 fb^{-1}. The observed numbers of events are in general agreement with…
Measurements of the production of events containing isolated high energy leptons (electrons and muons) produced in ep collisions have been performed with the H1 and ZEUS detectors at HERA, using data collected in the period 1994-2007.…
Inclusive jet and multijet cross sections measured in ep collisions in different kinematic regions by the H1 and ZEUS experiments are shown. The measurements are used to extract the strong coupling alpha_s as a function of the scale and at…
A search for events with an imbalance in transverse momentum and with isolated high energy leptons has been carried out at the positron-proton collider HERA. One event with an e^- and five events with a mu^+- are found together with…
Deep inelastic electron proton scattering at HERA II will allow precise studies of QCD and stringent tests of physics beyond the standard model. We discuss these two aspects of DIS with emphasis on the regime of high gluon densities at…
The latest results from the H1 and ZEUS collaborations which challenge the QCD description of high energy $ep$ collisions are presented. Data from HERA continue to provide precision measurements and are compared to the latest theoretical…
Under certain running conditions, the CERN Large Hadron Collider (LHC) can be considered as a photon-photon collider. Indeed, in proton-proton, proton-ion, ion-ion collisions, when incoming particles pass very close to each other in very…
The results of a measurement of the proton structure function F_2(x,Q^2)and the virtual photon-proton cross section are reported for momentum transfers squared Q^2 between 0.35 GeV^2 and 3.5 GeV^2 and for Bjorken-x values down to 6 10^{-6}…
The physics of polarized nucleon--nucleon collisions originating from an internal polarized target in the HERA proton beam is investigated. Based on 240 pb^-1 integrated luminosity at 40 GeV c.m. energy, statistical sensitivities are given…
A combination of the reduced $e^{\pm}p$ cross section, previously measured by H1 and ZEUS, has been performed and leads to well constrained QCD fits of the parton densities in the proton. These results, as well as the high-$Q^2$ neutral…
Recent results from the H1 and ZEUS Collaborations on inclusive single and multiple jet production in the neutral current deep inelastic scattering of electrons/positrons on protons and the high energy photoproduction on protons at HERA are…
Results are given on the measurements of the hard diffractive interactions at HERA $ep$ collider. The structure of the diffractive exchange in terms of partons and the factorisation properties are discussed, in particular by comparing the…
Searches for Physics beyond the Standard Model have entered an exciting new phase: the complete HERA data samples obtained until the end of operations in the Summer of 2007 are now available for analysis. ZEUS and H1 have each collected…
We present a search for excited electrons, neutrinos and quarks using the H1 detector at the $ep$ collider HERA, based on data taken in 1994 with an integrated luminosity of 2.75 pb$^{-1}$. Radiative decays of excited quarks and neutrinos…
A search for excited electron e* production is described in which the electroweak decays e*->e gamma, e*->e Z and e*->nu W are considered. The data used correspond to an integrated luminosity of 120 pb^(-1) taken in e^(+-)p collisions from…
The HERA collaborations, H1 and ZEUS, have searched for physics beyond the Standard Model in ep collisions at centre-of-mass energies of up to 319 GeV. In this article the experimental results coming from the HERA I phase are summarised and…
A search for excited electrons is performed using the full $e^{\pm}p$ data sample collected by the H1 experiment at HERA, corresponding to a total luminosity of 475 pb$^{-1}$. The electroweak decays of excited electrons…
The production of photons at very small angles with respect to the proton beam direction is studied in deep-inelastic positron-proton scattering at HERA. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to…
Recent measurements of inclusive and semi-inclusive deep inelastic scattering in electron-proton collisions at HERA are reviewed. These measurements are used to determine the parton distribution functions (PDFs) of the proton, a necessary…
The ALICE experiment at the Large Hadron Collider at CERN is optimized to study the properties of the hot, dense matter created in high energy nuclear collisions in order to improve our understanding of the properties of nuclear matter…