Related papers: Signals for Virtual Leptoquark Exchange at HERA
We study the production of composite scalar leptoquarks in $e\gamma$ colliders, and we show that an $e^+e^-$ machine operating in its $e\gamma$ mode is the best way to look for these particles in $e^+e^-$ collisions, due to the hadronic…
The exclusive diffractive production of vector mesons and real photons in ep collisions has been studied at HERA in a wide kinematic range. Here the most recent experimental results are presented together with a Regge-type model and…
Searches in ep collisions for heavy excited fermions have been performed with the ZEUS detector at HERA. Excited states of electrons and quarks have been searched for in e^+p collisions at a centre-of-mass energy of 300 GeV using an…
The cross sections for charged and neutral current deep inelastic scattering in e^+p collisions with a longitudinally polarised positron beam have been measured using the ZEUS detector at HERA. The results, based on data corresponding to an…
Standard parton distribution functions contain neither information on the correlations between partons nor on their transverse motion, then a vital knowledge about the three dimensional structure of the nucleon is lost. Hard exclusive…
New results on the Deeply Virtual Compton Scattering process $\gamma^* p \to \gamma p$ (DVCS) from H1 experiment at the $e p$ collider HERA are presented, using data collected during the year 2004 and corresponding to an integrated…
A search for events with a high energy isolated electron or muon and missing transverse momentum has been performed at the electron-proton collider HERA using an integrated luminosity of 13.6 pb-1 in e-p scattering and 104.7 pb-1 in e+p…
Vector Leptoquarks (VLQs) have emerged as primary candidates for resolving discrepancies in the Standard Model, specifically within $B$-meson decay channels and the anomalous magnetic moment of the muon. This work presents a rigorous…
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…
The ZEUS detector has been used to study dissociation of virtual photons in events with a leading proton, gamma^* p -> X p, in e^+p collisions at HERA. The data cover photon virtualities in two ranges, 0.03<Q^2<0.60 GeV^2 and 2<Q^2<100…
A search for lepton-flavor-violating interactions $e p \to \mu X $ and $e p\to \tau X $ has been performed with the ZEUS detector using the entire HERA I data sample, corresponding to an integrated luminosity of 130 pb^{-1}. The data were…
Searches for physics beyond the Standard Model are reported from electron-proton collisions at a center of mass energy of 318 GeV. Results on a completely model independent search for deviations from Standard Model predictions at large…
Hadronic antenna patterns can provide a valuable diagnostic tool for probing the origin of the apparent excess of high $x,Q^2$ events at HERA. We present quantitative predictions for the distributions of soft particles and jets in standard…
We perform a systematic analysis of scalar and vector leptoquark pair production at the Fermilab Tevatron and at the CERN LHC. We evaluate signal expectations and background levels for the processes pp (p ppar) -> 2 jets + e^{+} + e^{-} and…
Heavy excited electrons and neutrinos have been sought by the H1 and ZEUS experiments at HERA. For the e* (nu*) searches, 120 pb^-1 (16 pb^-1) of ep collision data have been analysed. No evidence for any excited lepton has been found, and…
Processes leading to a final state with at least two high transverse momentum leptons (electrons or muons) are studied using the full ep data sample collected by the H1 experiment at HERA. The data correspond to an integrated luminosity of…
A search for single top quark production is performed in the full ep data sample collected by the H1 experiment at HERA, corresponding to an integrated luminosity of 474 pb^-1. Decays of top quarks into a b quark and a W boson with…
In the context of HERA with polarized lepton and proton beams, we explore the sensitivity of the collider to contact interactions. We emphasize that the measurement of longitudinal spin asymmetries in such a polarized context could give…
We study pair production of leptoquarks in e+e- annihilation at linear colliders. A detailed simulation including beamstrahlung and initial state radiation, leptoquark decay and hadronization, as well as detector smearing, is performed.…
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…