Related papers: Signals for Virtual Leptoquark Exchange at HERA
A search for physics beyond the Standard Model has been performed with high-Q^2 neutral current deep inelastic scattering events recorded with the ZEUS detector at HERA. Two data sets, e^+ p \to e^+ X and e^- p \to e^- X, with respective…
The HERA collider with its center of mass energy of 318 GeV makes it possible to study a wide range of electroweak physics as well as to search for physics beyond the Standard Model (SM). In this article, recent results, obtained by the two…
The early observation at HERA of an excess of events compared to the expectation from the Standard Model in very short distance $e^+p$ deep-inelastic scattering processes has renewed the interest in the search for new physics which could…
An interpretation that the HERA excess events are due to intermediate production and decay of composite leptoquarks in the left-right symmetric preon model is given. Because of the preon-line rule, expected to be valid well, the event-ratio…
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…
A search for second and third generation scalar and vector leptoquarks produced in ep collisions via the lepton flavour violating processes ep to mu-X and ep to tau-X is performed by the H1 Collaboration at HERA. The full H1 ep data sample…
The scalar and vector leptoquark pair production cross sections for deep inelastic $ep$ scattering are calculated. Estimates are presented for the search potential at HERA.
I present a concise review of the possible evidence for new physics at HERA and of the recent work towards a theoretical interpretation of the signal. It is not clear yet if the excess observed at large Q^2 is a resonance or a continuum…
A search for first-generation leptoquarks was performed in electron-proton and positron-proton collisions recorded with the ZEUS detector at HERA in 2003-2007 using an integrated luminosity of 366 pb^-1. Final states with an electron and…
A search for single top quark production is performed in e^\pm p collisions at HERA. The search exploits data corresponding to an integrated luminosity of 118.3 pb^-1. A model for the anomalous production of top quarks in a flavour changing…
The excess of high-Q2 events recently observed in deep-inelastic positron-proton scattering at HERA has refuelled speculations on physics beyond the standard model, in particular on low-mass leptoquark-type particles. We review the…
A search for second and third generation scalar and vector leptoquarks produced in ep collisions via the lepton flavour violating processes ep -> mu X and ep -> tau X is performed by the H1 experiment at HERA. The full H1 ep data sample…
The four fermion contact interactions, required to explain the anomalous HERA result, could come from the exchange of new heavy (probably composite) resonances. Depending on their charges and quantum numbers, one gets different scenarios…
Recent results of searches for new physics at HERA using the complete data sample corresponding to about 0.5/fb per experiment are reviewed. Searches for leptoquarks, isolated leptons (electrons, muons and taus) and a generic search for new…
The inclusive e^-p single and double differential cross sections for neutral and charged current processes are measured with the H1 detector at HERA, in the range of four-momentum transfer squared Q^2 between 150 and 30000 GeV^2, and…
In this talk I summarize the capability of future lepton colliders to discover leptoquarks and to determine their electroweak quantum numbers. This analysis is an updated discussion based on the results presented in the Snowmass 1996 New…
The HERA ep collider and the experiments H1 and ZEUS operated from 1994-2007. A total integrated luminosity of almost 1 fb^-1 was collected at centre-of-mass energies up to 320 GeV. Results from searches for leptoquarks and squarks, final…
A light stop, with an R-parity-violating coupling $\lambda'_{131}$, has been suggested as an explanation of the excess in high-$Q^2$ neutral current events observed at the HERA collider. We show that in this scheme a corresponding excess in…
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…
In a first step, we explore the discovery and analysis potentials of the HERA collider, with and without polarized beams, in the search for electron-quark compositeness in the neutral current channel. Then we study the parity violating…