Related papers: An anomalous Wtb coupling at a linear collider
We analyze constraints on the anomalous $Wtb$ couplings from $B$-physics experiments, performing a correlated analysis and allowing all anomalous couplings to differ simultaneously from their Standard-Model (SM) values. The $B$-physics…
The potential of LHC for investigation of the $W$-$t$-$b$ vertex through the $tW$ channel of single top quark production is studied. Unlike the other two single top quark production processes ($t-$channel and $s-$channel), the $tW$ channel…
As the heaviest known fundamental particle, the top quark ensures testing of the Standard Model and occupies a significant role in a lot of theories of new physics beyond the Standard Model. Up to now, the top quark has been only generated…
In the presence of an electric dipole coupling of $t \bar t$ to a photon, and an analogous ``weak" dipole coupling to the $Z$, $CP$ violation in the process $e^+e^- \rightarrow t \bar t$ leads to the polarization of the top and anti-top.…
In ongoing and upcoming hadron collider experiments, top quark physics will play an important role in testing the Standard Model and its possible extensions. In this work we present analytic results for the differential cross sections of…
We discuss top quark production and its subsequent decay for searching new physics at lepton colliders. The angular dependence of the decay leptons is calculated including both QCD corrections and anomalous gamma Z - t tbar couplings. The…
We consider the electroweak production of a top quark in association with a photon at the LHC to probe the electroweak top quark couplings (t$\bar{\text{t}}\gamma$) as well as the triple gauge boson couplings (WW$\gamma$). The study is…
We investigate the possibility that an imaginary anomalous $tbW$ coupling can be measured in the process $e^-p \to \nu_e \overline t X$ by means of T-odd observables. One such observable considered here is the polarization of the top…
The dimension-four genuine anomalous quartic couplings are studied in processes of six-fermion production via e+e- collisions. Complete tree-level electroweak calculations are performed including initial-state-radiation and beamstrahlung.…
An optimal-observable analysis of the angular and energy distributions of the leptons and bottom quarks in the process e+e- --> tt-bar --> l^{+-}/b(b-bar)... has been performed in order to measure the most general top-quark couplings to…
Results of complete tree level calculations of the single top production reaction $\gamma e \to \nu \bar{t} b$ at the Next Linear Collider, including the contribution of anomalous operators to the Wtb coupling are presented. The sensitivity…
In the presence of an electric dipole coupling of t-tbar to a photon, and an analogous "weak" dipole coupling to the Z, CP violation in the process e+e- --> t tbar results in modified polarization of the top and anti-top. This polarization…
In an effective operator approach, the full set of leading contributions to anomalous top couplings comprises various new trilinear as well as higher interaction vertices, some of which are related to one another by gauge symmetry or…
We investigate the effect of anomalous gamma-W-W couplings in e-gamma --> nu W through the angular and energy spectrum of the secondary leptons. Within the narrow-width approximation, a semi-analytical study of the secondary lepton…
The electroweak production and subsequent decay of single top quarks is determined by the properties of the $Wtb$ vertex. This vertex can be described by the complex parameters of an effective Lagrangian. An analysis of angular…
We make a complete one loop calculation of the $tbW$ couplings in the Two Higgs Doublet Model. We evaluate both the anomalous couplings $g_L$ and $g_R$ as well as left handed and right handed component of $tbW$. The computation is done in…
We investigate the possibility that an imaginary anomalous $tbW$ coupling can be measured in the process $pp \to tW^-X$ by means of T-odd observables. One such observable is the polarization of the top quark transverse to the production…
We study the possibility for the process $pp \rightarrow p\gamma p \rightarrow pW^-t(W^+\bar t)X$ with anomalous Wtb couplings in a model independent effective Lagrangian approach at the LHC. We find 95% confidence level bounds on the…
The energy spectra of the lepton(s) in eebar --> ttbar --> l^{+-}X/ l^+l^- X' at next linear colliders (NLC) are analyzed a model-independent way for arbitrary longitudinal beam polarizations as a general test of possible anomalous…
CP-violating asymmetries in the processes e+e- -> t tbar and gamma gamma -> ttbar can provide information about CP-violating couplings of the top quark, whose presence would signal physics beyond the standard model. Work on studies of…