Related papers: Four-top production and t tbar + missing energy ev…
We study production of t {\bar t} via W^+ W^- fusion, including the relevant backgrounds at the proposed Linear Collider (an e^+ e^- collider with \sqrt{S} = 1.5 TeV) in the context of a Higssless Standard Model (SM), i.e. a nonlinear…
We present the results of a search for pair production of scalar top quarks in an R-parity violating supersymmetry scenario in 106 pb-1 of ppbar collisions at $\sqrt{s} = 1.8$ TeV collected by the Collider Detector at Fermilab. In this mode…
The results of a search for direct pair production of top squarks in events with two opposite-charge leptons (electrons or muons) are reported, using 36.1 fb$^{-1}$ of integrated luminosity from proton--proton collisions at $\sqrt{s}=13$…
We discuss associated production of a Higgs boson with a pair of $t {\bar t}$ quarks at a future high energy $e^+e^-$ collider. The process $e^+e^-\to t {\bar t}h$ is particularly sensitive to the presence of new physics and we consider the…
Precise measurements of the properties of the top quark test the Standard Model (SM) and can be used to constrain new physics models. The top quark pair charge asymmetry is an asymmetry predicted to occur beyond leading-order QCD in the SM,…
A supersymmetric model with four generations is proposed, in which the top quark is approximately degenerate in mass with the $W^{\pm}$ gauge boson, $m_t\simeq m_W$, leading to values of $R_b$ in better agreement with the present…
Top quarks represent unique high-energy systems since their spin correlations can be measured, thus allowing to study fundamental aspects of quantum mechanics with qubits at high-energy colliders. We present here the general framework of…
Measurements of top quark production at $e^+e^-$ colliders can provide a leap in precision in our knowledge of top quark properties and open a new window on physics beyond the Standard Model. In this contribution the top quark physics…
A search is presented for standard model (SM) production of four top quarks (t t-bar t t-bar) in pp collisions in the lepton + jets channel. The data correspond to an integrated luminosity of 19.6 inverse femtobarns recorded at a…
A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb$^{-1}$ collected by the CMS experiment, is…
Heavy quark production in five jet events at $e^+e^-$ colliders is studied at tree level using helicity amplitudes. Total production rates for $2b3j$ and $4bj$ are given and compared with the corresponding results for massless quarks. The…
The mechanism of the electroweak symmetry-breaking (EWSB) is studied in the context of the heavy top quark, whose large mass may provide a clue as to the mechanism which generates the mass of the $W^\pm$ and $Z$ bosons. As a result, it…
The process of top-quark pair production followed by semileptonic decays at future high-energy e^+e^- linear colliders is investigated as a possible test of physics beyond the Standard Model. Assuming the most general non-standard forms for…
Cross-sections for hadronic, b-bbar and lepton pair final states in e+e- collisions at sqrt(s) = 183 GeV, measured with the OPAL detector at LEP, are presented and compared with the predictions of the Standard Model. Forward-backward…
We have searched for production of t-tbar pairs in p-pbar interactions at 1.8 TeV center-of-mass energy at the FNAL Tevatron collider. The search assumes standard model decay for top quark into W + b quark. We observe in e+jet and mu+jet…
Data collected by the D0 detector at a p-pbar center-of-mass energy of 1.96 TeV at the Fermilab Tevatron Collider have been used to search for pair production of the lightest supersymmetric partner of the top quark decaying into $b \ell…
Searches for new physics in the top-quark sector using data from proton-antiproton collisions at the Fermilab Tevatron are discussed. The large data sets collected by the D0 and CDF experiments allow for precision measurements of the…
We analyze the manifestations of new matter particles predicted by models of new physics beyond the Standard Model, at present and future high--energy colliders. We consider both the production of these new particles and some of their…
This paper describes a search for events with one top-quark and large missing transverse momentum in the final state. Data collected during 2015 and 2016 by the ATLAS experiment from 13 TeV proton-proton collisions at the LHC corresponding…
We study the sensitivity of $ e \gamma$ colliders to physics beyond the Standard Model, when such interactions are natural and their scale lies below the collider energy. Using the reaction $ e \gamma \to b t \nu$ as a specific example, we…