相关论文: Top polarisation studies in $H^-t$ and $Wt$ produc…
The top quark pairs produced at a polarized muon collider are in a (nearly) pure spin configuration. This result holds for all center-of-mass energies, and is insensitive to the next-to-leading order QCD radiative corrections. The decay…
Angular and energy distributions for leptons and bottom quarks in the process e^+e^- --> t t-bar --> l^{+-}/b(b-bar) ... have been calculated assuming the most general top-quark couplings. The double distributions depend both on…
We calculate the density matrix for the decay of a polarised top quark into a polarised W boson and a massive b quark, for the most general Wtb vertex arising from dimension-six gauge-invariant effective operators. We show that, in addition…
Top quark polarization provides an important tool for studying its production mechanisms, spin correlations, top quark properties, and new physics searches. Unlike lighter quarks, the top quark's polarization remains intact until its decay,…
We analyze, within several parameter scenarios of type-II two-Higgs doublet extensions of the standard model, the impact of heavy neutral Higgs-boson resonances on top-quark pair production and their subsequent decay to dileptonic final…
The uncertainty of $t\bar{t}$ production cross section measurement at LHC is at a-few-percent level which still allows the stop pair production $\tilde{t}\tilde{t}^{*}$ with identical final states $2b+\ell+nj+{E}_{T}$. In this paper, we…
In most of the models beyond the Standard Model, the top quark is expected to be polarized when produced in the decay of some heavier particle, like the gluino or the stop. The polarization is constructed, in an experiment or in…
We put forward a method to tune the polarisation state of decaying heavy particles (top quarks and $W/Z$ bosons) in a pre-existing Monte Carlo sample. With this technique, dubbed as `custom angle replacement', the decay angular…
We survey the expected polarization of the top produced in the decay of a scalar top quark, $\tilde t \rightarrow {\tilde t}\chi_i^0, i =1-2$. The phenomenology is quite interesting, since the expected polarization depends both on the…
Top-antitop pairs produced at hadron colliders are largely unpolarized, but their spins are highly correlated. The structure of these correlations varies significantly over top production phase space, allowing very detailed tests of the…
Measuring top polarization is extremely important in understanding any new physics that couples to top quark. Here, we take up the task of extracting polarization of top quark coming from TeV-scale stop decay at the upgraded high luminosity…
This thesis presents a study of the prospects of measuring electroweak production of the top quark at the LHC. The study of the top quark is a highly topical subject as we expect significant numbers of top quarks at the LHC which will…
A number of top-spin observables are computed within the Standard Model (SM), at next-to-leading order in the strong and weak gauge couplings for hadronic top-quark anti-quark (ttbar) production and decay at the LHC for center-of-mass…
The measurement of the top quark polarization, sensitive to the electroweak coupling structure, in t-channel single-top production is presented. Events are analyzed corresponding to an integrated luminosity of approximately…
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…
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…
Theoretical results are presented for top quarks produced in annihilation of polarized electrons on positrons. Polarization studies for $t\bar t$ pairs near threshold are free from hadronization ambiguities. This is due to the short…
We introduce a new asymmetry in the decay t -> W b -> l nu b, which is shown to be directly proportional to the polarisation of the top quark along a chosen axis, times a sum of W helicity fractions. The latter have already been precisely…
We consider top quark production and decay in the narrow width approximation and study if the polarisation effects, that manifest themselves in correlations of angular distributions of particles from top quark decays and final state jets in…
The degree of top polarization and strength of $t\bar{t}$ correlation are dependent on production dynamics, decay mechanism, and choice of the observables. At the LHC, measurement of the top polarization and spin correlations in $t\bar{t}$…