No Arabic abstract
The analysis of $W$ production and the search for anomalous single top production is performed with the H1 detector at HERA with an integrated luminosity of 0.5 fb$^{-1}$, consisting of the complete high energy data from the HERA programme. Production cross section measurements of single $W$ production, as well as $W$ polarisation fractions in events containing isolated leptons and missing transverse momentum are also presented. In the context of a search for single top production an upper limit on the top production cross section $sigma_{epto etX} < 0.16$ pb is established at the 95% confidence level, corresponding to an upper bound on the anomalous magnetic coupling $kappa_{tugamma} < 0.14$.
A search for single top production in ep collisions using the complete high energy data from HERA is presented. This search is based on the analysis of events containing isolated leptons (electrons or muons) and missing transverse momentum PTmiss. In the absence of a signal, an upper limit on the top production cross section sigma_ep -> etX < 0.16 pb is established at the 95% confidence level, corresponding to an upper bound on the anomalous magnetic coupling kappa_tug < 0.14. The search is complemented by a search for events containing an isolated tau lepton and PTmiss and the measurement of W boson polarisation fractions.
A search for single-top production, $ep rightarrow etX$, has been performed with the ZEUS detector at HERA using data corresponding to an integrated luminosity of $0.37fbi$. No evidence for top production was found, consistent with the expectation from the Standard Model. Limits were computed for single-top production via flavour changing neutral current transitions. The result was combined with a previous ZEUS result yielding a total luminosity of 0.50fb-1. A 95% credibility level upper limit of 0.13 pb was obtained for the cross section at the centre-of-mass energy of $sqrt{s}=315gev$.
Results on open charm and beauty production and on the search for top production in high-energy electron-proton collisions at HERA are reviewed. This includes a discussion of relevant theoretical aspects, a summary of the available measurements and measurement techniques, and their impact on improved understanding of QCD and its parameters, such as parton density functions and charm- and beauty-quark masses. The impact of these results on measurements at the LHC and elsewhere is also addressed.
Updates of electroweak single top quark production measurements by the D0 collaboration are presented using 5.4fb^-1 of proton-antiproton collision data from the Tevatron at Fermilab. Measurements of the t-channel, s-channel and combined single top quark production cross section are presented, including an updated lower limit on the CKM matrix element |V_tb|. Also reported are results from searches for gluon-quark flavor-changing neutral currents and W boson production.
In the energy region of LEP2 and above, four fermion final states in e+e- collisions can be produced by Feynman diagrams involving two, one or zero resonant bosons...