Related papers: Boosted Top quark polarization
The existence of new coloured states with spin one-half, i.e. extra-quarks, is a striking prediction of various classes of new physics models. Should one of these states be discovered during the 13 TeV runs of the LHC or at future high…
Longitudinal polarization of the top quark, averaged over the production angle, is discussed for the top quark produced in e+e- annihilation near its production threshold. It is demonstrated that Coulomb type corrections and rescattering…
Polarized $\Lambda_b \to \Lambda \gamma$ decays at the Z pole are shown to be well suited for probing a large variety of New Physics effects. A new observable is proposed, the angular asymmetry between the $\Lambda_b$ spin and photon…
We investigate the sensitivity to new physics of the process e+e- -> t bar{t} when the top polarization is analyzed using leptonic final states e+e- -> t \bar{t} -> l+l- b \bar{b} nu_l \bar{nu}_l. We first show that the kinematical…
Top quark pair production at photon-photon colliders is studied in low scale quantum gravity scenario. From the dependence of the cross sections on the spin configuration of the top quark and anti-quark, we introduce a new observable, top…
We provide a framework for the analysis of the W boson helicity in the decay of the top quark that is based on a general effective tbW coupling. Four independent coupling coefficients can be uniquely determined by the fractions of…
We study pair production of scalar top quarks in polarized photon-photon collisions with the subsequent decay of the top squarks into b-quarks and charginos. We simulate this process by using PYTHIA6.4 for an electron beam energy 2E_beam…
Complete analytical results for the production of heavy-quark pairs by polarized and unpolarized photons in next-to-leading order are presented. Two-, three- and two plus three-jet cross sections for total photon spin $J_z=0,\pm 2$ are…
Search for new-physics through possible anomalous t tbar gamma, tbW and gamma gamma H couplings which are generated by SU(2) X U(1) gauge-invariant dimension-6 effective operators is discussed, using energy and angular distributions of…
In this paper we study new-physics contributions to the top-quark decay $t \to b \bar b c$. We search for ways of detecting such new physics via measurements at the LHC. As top quarks are mainly produced at the LHC in $t \bar t$ production…
Angular distribution of a secondary particle in top-quark production/decay is studied in a simple and general manner. It is shown that the distribution does not depend on any possible anomalous top-quark-decay interactions whatever the…
Models of top condensation can provide both a compelling solution to the hierarchy problem as well as an explanation of why the top-quark mass is large. The spectrum of such models, in particular topcolor-assisted technicolor, includes…
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…
Spin correlations in the t-channel single top quark production and its subsequent decay are investigated for the case of contributions involving anomalous Wtb couplings. We obtain analytical expressions for the differential widths for the…
The top quark plays an important role in searches for physics beyond the SM, both as a dominant background and as a key signature for the signal. The most notable feature found in the top physics analyses in both ATLAS and CMS…
We study the production of a heavy charged Higgs boson at the Large Hadron Collider (LHC) in $gb\to H^{-} t$ within a Two Higgs Doublet Model (2HDM). The chiral structure of the $H^{-} t \bar{b}$ coupling can trigger a particular spin state…
Top tagging is a recent approach to identifying boosted hadronic top quarks. It avoids reconstructing individual top decay products and instead uses a jet algorithm to reconstruct the entire top decay. Quite generally, geometrically large…
We present the azimuthal correlations in the decay products of the top quark pair created in the process $gg \to t \tbar \to b \bbar \wplus \wminus$ calculated in leading-order QCD. We then discuss deviations in this distribution that could…
Analytic expression for energy and angular dependence of a secondary charged lepton in the decay of a polarized top quark with anomalous $tWb$ couplings in the presence of all anomalous couplings are derived. The angular distribution of the…
We propose two new observables to measure the charge asymmetry in hadronic top-quark pair production in association with a hard jet. The incline asymmetry, based on the inclination between the planes of initial- and final-state momenta,…