相关论文: Contact Interactions and high-Q2 events in e^+ p c…
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…
Possible interpretations of the HERA large-Q^2 data are reviewed briefly. The possibility of statistical fluctuations cannot be ruled out, and it seems premature to argue that the H1 and ZEUS anomalies are incompatible. The data cannot be…
The latest status of searches at HERA for physics beyond the Standard Model is summarized on behalf of the H1 and ZEUS collaborations. Emphasis is put on production of resonant particles accessible within the HERA center-of-mass energy,…
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…
We investigate a production process $e^+p \to \st X \to \sb W^+ X$ at HERA, where we consider a decay mode $\sb \to \bar{\nu}_e d$ of the sbottom in the framework of an R-parity breaking supersymmetric standard model. Both processes of the…
The search for events containing isolated leptons and missing transverse momentum produced in ep collisions is performed individually and in a common phase space with the H1 and ZEUS detectors at HERA. The combined H1 and ZEUS data sample…
The latest results from the H1 and ZEUS collaborations are presented on leptoquark production and rare Standard Model processes. The data were taken in the period 1994-2005, at a centre of mass energy of up to 319 GeV. Intriguing events…
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…
The latest results of H1 and ZEUS on the electroweak cross sections using polarised lepton beams are presented with the improvements in the parton density functions that result from them. The asymmetry of the neutral current cross sections…
Studies of charm and beauty production in ep collisions with a center-of-mass energy of 318 GeV are reported from the two HERA collaborations, H1 and ZEUS. The analyses make use of both the HERA-I data sample recorded between 1996 and 2000…
An extended study of exclusive vector meson production in e,p interactions has been performed by the H1 and the ZEUS collaborations at the HERA collider. Recent measurements are reported and discussed within the framework of the dipole…
A search for excited neutrinos, the analysis of multi-lepton final states, a search for doubly charged Higgs production and a general search for high-Pt phenomena at HERA are reported. The searches use data samples of ep collisions with a…
The electron-proton collisions collected by the H1 and ZEUS experiments at HERA comprise a unique particle physics data set, and a comprehensive range of measurements has been performed to provide new insight into the structure of the…
Deep inelastic charged--current reactions have been studied in $e^+p$ and $e^-p$ collisions at a center of mass energy of about $300\,\gev$ in the kinematic region $Q^2\greater200\,\gev^2$ and $x\greater0.006$ using the ZEUS detector at…
The recently reported excess of events at HERA compared to QCD calculations impels us to examine all possible Standard Model explanations before invoking ``new physics''. We explore the possibility of adding an unusual, but small, component…
In reference to the recently observed high Q^2, large x events in deep-inelastic positron-proton scattering at HERA, various leptoquark and supersymmetric scenarios are discussed. We study the impact of virtual leptoquark or R-parity…
We have searched for the production of a selectron and a squark in $e^+p$ collisions at a center-of-mass energy of 300 GeV using the ZEUS detector at HERA. The selectron and squark are sought in the direct decay into the lightest neutralino…
The hadron production in $e^+e^-$ collisions is studied assuming that particles originate in a hadron gas at thermal and chemical equilibrium. The parameters of the hadron gas are determined with a fit to the average multiplicities of…
Details are given of the observation by H1 of events containing high P_T leptons in addition to large missing P_T. A closely related ZEUS analysis, including a preliminary measurement of the W production cross section, is discussed and the…
Fermion compositeness and other new physics can be signalled by the presence of a strong four-fermion contact interaction. Here we present a study of $\ell\ell qq$ and $\ell\ell\ell'\ell'$ contact interactions using the reactions: $\ell^+…