Related papers: Signals for Virtual Leptoquark Exchange at Collide…
The cross section of single vector leptoquark production in direct lepton-gluon interaction is calculated. In a model independent analysis an effective Lagrangian describing the most general $C$ and $P$ conserving coupling of the…
We describe new QCD fits to diffractive cross sections measured at HERA and we use the parton densities derived from these fits to predict the shape of the dijet mass fraction in double Pomeron exchange at the Tevatron. We discuss the…
We analyze the effects of Scalar and Vector Leptoquarks on various observables in electron (positron) - proton deep inelastic scattering. In view of the future program of the HERA collider, with a high luminosity and also with polarization,…
We demonstrate that in the presence of mixing between different scalar leptoquark multiplets it is possible to simultaneously account for the HERA high-$Q^2$ neutral current anomaly, and produce a charged current anomaly of comparable…
The cross sections for the formation of scalar resonances, leptoquarks or squarks, in electron/positron-proton collisions at HERA are presented including next-to-leading order QCD corrections. Depending mildly on the mass of the resonances,…
Data from the Large Electron Positron collider (LEP) at CERN on hadron production in gamma-gamma interactions exceed the predictions of the standard model by an order of magnitude at the highest observed transverse momenta in three…
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 data sample taken at…
We present the results of an analysis for the pair production of scalar leptoquarks at the CERN Large Hadron Collider (LHC) with energy=14 TeV and luminosity=10 fb^{-1} which includes the dominant sources of Standard Model background…
We calculate the cross section for the production of pairs of scalar leptoquarks (sleptoquarks) in a supersymmetric $E_6$ model, at hadron colliders. We estimate higher order corrections by including $\pi^2$ terms induced by soft-gluon…
Recent theories propose that quantum gravity effects may be observable at LEP energies via gravitons that couple to Standard Model particles and propagate into extra spatial dimensions. The associated production of a graviton and a photon…
Recent results on searches for physics beyond the Standard Model obtained by the H1 and ZEUS experiments are reported here. After a brief introduction to the HERA collider, indirect searches for contact interactions and extra-dimensions are…
Exclusive photoproduction of dileptons, gamma p ->l+ l- p, will be measured in ultraperipheral collisions at LHC. The mechanism where the lepton pair comes from a heavy timelike photon radiated from a quark interferes with the pure QED…
The physics of diffractive vector meson production in virtual photon nucleon scattering at NMC energies is reviewed. A particular attention is paid to the physical aspects of the reaction and how they influence the observables. The reaction…
We explore the discovery and analysis potentials of the HERA collider, with and without polarized beams, in search for electron-quark contact interactions in the neutral current channel. We find that the sensitivity to contact interactions…
A summary is given on the experimental bounds for the couplings and masses of scalar and vector leptoquarks associated to the first fermion generation. We investigate to which extent an interpretation of the recently reported excess of…
We perform a detailed analyses of the CERN Large Hadron Collider (LHC) capability to discover first generation vector leptoquarks through their pair production. We study the leptoquark signals and backgrounds that give rise to final states…
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…
Multi-electron and multi-muon production at high transverse momentum is measured in $ep$ scattering at HERA. Previous published analyses are extended, combining new HERA II data taken in 2003-2004 with previous HERA I data sample. In…
We show that the current bounds on the leptoquark couplings imply that if leptoquarks are produced in e p collisions, a significant fraction of them could form a leptoquark-quark bound state. The decay of the bound state has a distinct…
A review is given of the measurements of the hard diffractive interactions in recent years from two high-energy colliders, the HERA $ep$ collider and the Tevatron $p\bar{p}$ collider. The structure of the diffractive exchange in terms of…