Related papers: Top mixing
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…
In this paper we introduce a simple renormalizable model of an extended color gauge sector in which the third-generation quarks couple differently than the lighter quarks. In addition to a set of heavy color-octet vector bosons (colorons),…
The extension of the Standard Model with exotic quark singlets and doublets introduces large flavor changing neutral couplings between ordinary fermions. We derive inequalities which translate the precise determination of the diagonal Z…
The formation of hadrons is a fundamental process in nature that can be investigated at particle colliders. As several recent findings demonstrate, with $\mathrm{e^+e^-}$ collisions as a "vacuum-like" reference at one extreme, and central…
In theories of Partial Compositeness the top quark is a mixture of a composite and an elementary state, and as a consequence its interactions with gauge bosons are expected to deviate from those of a point-like object. At sufficiently large…
A study of the top quark interactions via flavour-changing neutral current (FCNC) processes provides an intriguing connection between the heaviest elementary particle of the standard model (SM) of particle physics and the new scalar bosons…
We present a search for flavor changing neutral currents via quark-gluon couplings in a sample of single top quark final states corresponding to 2.3 fb^-1 of integrated luminosity collected with the D0 detector at the Fermilab Tevatron…
The mixing of the known quarks with new heavy singlets can modify significantly some observables with respect to the Standard Model predictions. We analyse the range of deviations permitted by the constraints from precision electroweak data…
The top quark flavor changing neutral current (FCNC) processes are extremely suppressed within the Standard Model (SM) of particle physics. However, they could be enhanced in a new physics model Beyond the Standard Model (BSM). The top…
Top decays into a light Higgs boson and an up or charm quark can reach detectable levels in Standard Model extensions with two Higgs doublets or with new exotic quarks, and in the Minimal Supersymmetric Standard Model. Using both a standard…
Using the constraint on the single top production cross-section obtained at the HERA collider, $\sigma(ep \to e t X)$, we evaluate an upper limit on oupling constant of the anomalous top quark interaction with a gluon via flavor-changing…
We study low energy experimental constraints on an anomalous top-quark coupling associated with the flavor-changing neutral current vertex $Z \bar t c$. In view of these constraints, we discuss the experimental observability of the induced…
The precise calculations are carried out on the flavor changing neutral current couplings in the process $pp \to gg \to t\bar{c}(\bar{t}c)$ at the large hadron collider(LHC) and very large hadron collider(VLHC) in both frameworks of the…
We review the model-independent description of the couplings of the top quark to the Higgs and gauge bosons in theories beyond the Standard Model. Then we examine these couplings in the case of arbitrary heavy vector-like quarks mixing with…
Within the model-independent framework of $SU(3)\times SU(2)\times U(1)$ gauge-invariant dimension-six operators, we study flavor-changing $Wtq$ couplings ($q=d,s$) and related four-quark contact interactions involving the top. We obtain…
An overview of top physics and phenomenology at a high-energy linear collider is presented. A comprehensive study of top quark physics is possible at such a facility. The unique threshold production of top pairs would provide measurements…
There is growing interest in the development of a muon collider that would make it possible to produce lepton collisions at energies of several TeV. Among others, there can be significant contributions to electroweak gauge boson, Higgs…
We search for the production of single top quarks via flavor-changing neutral current couplings of a gluon to the top quark and a charm (c) or up (u) quark. We analyze 230 pb^{-1} of lepton+jets data from \ppbar collisions at a center of…
We study top quark flavor violation in the framework of a warped extra dimension with the Standard Model (SM) fields propagating in the bulk. Such a scenario provides solutions to both the Planck-weak hierarchy problem and the flavor puzzle…
The top quark flavor changing neutral current processes are extremely suppressed within the Standard Model. Nevertheless, they could be enhanced in a new physics model beyond the Standard Model. Investigating the top quark's flavor changing…