Related papers: Top-Charm Associated Production at High Energy e^+…
We study a new class of flavor changing interactions, which can arise in models based on extended gauge groups (rank $>$4) when new charged fermions are present together with a new neutral gauge boson. We discuss the cases in which the…
We discuss the existing limits on top flavour-changing neutral couplings in models with new vector-like quarks. Large hadron and e+ e- colliders can improve these bounds by more than one order of magnitude.
We present new measurements of the single top quark production cross section in \ppbar collisions at $\sqrt{s} = 1.96 TeV$ using data corresponding to 5.4 \ifb of integrated luminosity collected by the {\dzero} detector at the Fermilab…
We extend and improve upon our previous calculation of electroweak top-quark pair hadroproduction in extensions of the Standard Model with extra heavy neutral and charged spin-1 resonances. In particular, we allow for flavour-non-diagonal…
We present the complete next-to-leading order (NLO) QCD corrections to the top quark associated with $\gamma$ production induced by model-independent $tq\gamma$ and $tqg$ flavor-changing neutral-current (FCNC) couplings at hadron colliders,…
The forward-backward asymmetry $A_{FB}$ in top quark pair production, measured at the Tevatron, is probably related to the contribution of new particles. The Tevatron result is more than a $2\sigma$ deviation from the standard model…
A search for flavour-changing neutral-current processes in top-quark decays is presented. Data collected with the ATLAS detector from proton-proton collisions at the Large Hadron Collider at a centre-of-mass energy of $\sqrt{s}=13$ TeV,…
At hadron colliders, top quarks are dominantly produced in pairs ($t\bar{t}$), a production mechanism that was discovered more than twenty years ago at the Tevatron in Fermilab. Although the \ttbar process has already entered the domain of…
This paper presents the combinations of single-top-quark production cross-section measurements by the ATLAS and CMS Collaborations, using data from LHC proton-proton collisions at $\sqrt{s}=7$ and 8 TeV corresponding to integrated…
Results are presented on a measurement of the ttbar pair production cross section in ppbar collisions at sqrt{s} = 1.8 TeV from nine independent decay channels. The data were collected by the Dzero experiment during the 1992-1996 run of the…
We compute the branching ratios for the rare top quark decays t to c gamma and t to c Z mediated by effective flavor changing neutral couplings at the next-to-leading order in QCD including the effects due to operator mixing. After…
An updated measurement of the single top quark production cross section is presented using the full data set collected by the Collider Detector at Fermilab (CDF) and corresponding to 9.5 fb${}^{-1}$ of integrated luminosity from…
Associated single top production with a Z boson or a photon at large hadron colliders provides a precise determination of top flavour-changing neutral couplings. The best way to measure these couplings with the up quark at Tevatron is to…
The top-charm associated productions via $e^+ e^-$, $e^- \gamma$ and $\gamma \gamma$ collisions at linear colliders, which are extremely suppressed in the Standard Model (SM), could be significantly enhanced in some extensions of the SM. In…
We present a measurement of the top quark pair ($t\bar{t}$) production cross section ($\sigma_{t\bar{t}}$) in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV using 230 pb$^{-1}$ of data collected by the D0 experiment at the Fermilab Tevatron…
We present the measurement of the production cross section for top quark pair ($t\bar{t}$) in pp collisions at $\sqrt{s}$ = 7 TeV using the data recorded with the ATLAS detector at the Large Hadron Collider (LHC). Events are selected in…
Single top quarks in the $t$ channel are produced though the electroweak force and are therefore an excellent way to probe the electroweak sector of the standard model with top quark physics. The recent cross section measurement of single…
The total cross section for top quark pair production close to threshold in e+e- annihilation is investigated. Details are given about the calculation at next-to-next-to-leading logarithmic order. The summation of logarithms leads to a…
We present a measurement of the top quark pair ttbar production cross section in ppbar collisions at a center-of-mass energy of 1.96 TeV using 230 pb**{-1} of data collected by the DO detector at the Fermilab Tevatron Collider. We select…
In the framework of topcolor-assisted technicolor model we calculate the contributions from the pseudo Goldstone bosons and new gauge bosons to $e^+e^- \to t\bar{t}$. We find that, for reasonable ranges of the parameters, the pseudo…