相关论文: QCD effects and search for new physics in t -->b W
We present the NLO QCD corrections to the production of a W+W- pair and two b-jets, including the leptonic decays of the W bosons. Contributions from singly resonant and non-resonant top quarks are fully taken into account. We also discuss…
Precise measurements of the top quark decay properties at hadron colliders offer interesting new possibilities of testing the standard model. At the same time, recent intriguing experimental results concerning CP violation in the B_d and…
The search for new physics in top quark decays at the LHC is reviewed in this paper. Results from ATLAS and CMS experiments on top quark decays within the Standard Model are presented together with the measurements of the W boson…
We present a measurement of the fractions F_0 and F_+ of longitudinally polarized and right-handed W bosons in top-quark decays using data collected with the CDF II detector. The data set used in the analysis corresponds to an integrated…
We present a measurement of the fraction f_+ of right-handed W bosons produced in top quark decays, based on a candidate sample of ttbar events in the l+jets and dilepton decay channels corresponding to an integrated luminosity of 370 pb^-1…
We present a calculation of the next-to-leading-order QCD and electroweak corrections to WWW production with leptonically decaying $\mathrm{W}$ bosons at the LHC, fully taking into account off-shell contributions, intermediary resonances,…
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…
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…
This paper presents measurements of the polarization of W bosons in top quark decays, derived from ttbar events with missing transverse momentum, one charged lepton and at least four jets, or two charged leptons and at least two jets. Data…
We compute theoretical predictions for the production of a W-boson in association with a bottom-quark pair at hadron colliders at next-to-next-to-leading order (NNLO) in QCD, including the leptonic decay of the W-boson, while treating the…
We write down the four-dimensional fully differential decay distribution for the top quark decay $t \to Wb \to \ell \nu b$. We discuss how its eight physical parameters can be measured, either with a global fit or with the use of selected…
It is shown that up to an over all scale the lowest-order QCD corrections to $t\to H^+b$ and to $t\to W^+b$ are the same in the heavy top limit. Asymptotically, they are given by $-{4\alpha_s\over 3\pi}[{\pi^2\over 3}-{5\over 4}]$,…
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…
Fully reconstructed top-antitop-events are used to determine the fractions of right-handed and longitudinally polarized W bosons produced in top-quark decays. The helicity fractions are sensitive to the couplings and the Dirac structure of…
We present O(\alpha_s) results on the decays of polarized W^+- and Z bosons into massive quark pairs. The NLO QCD corrections to the polarized decay functions are given up to the second order in the quark mass expansion. We find a…
Stringent tests on top quark production and decay mechanisms are provided by the measurement of the top quark and W boson polarization. This paper presents a detailed study of these two measurements with the ATLAS detector, in the…
Over a decade since the discovery of the top quark we are still trying to unravel mysteries of the heaviest observed particle and learn more about its nature. The continuously accumulating statistics of CDF and Dzero data provide the means…
We study some New Physics effects on the hadronic decays of the Top quark, like t-> b bbar c, and on a forward-backward-like CP even asymmetry A_t constructed in such a way that it is zero in the SM. We find that an anomalous right-handed…
The one-loop supersymmetric QCD quantum effects on the width of the unconventional top quark decay mode $t\rightarrow H^{+}\, b$ are evaluated within the MSSM. The study of this process is useful to hint at the supersymmetric nature of the…
We present analytical results for top-quark decay processes, in an effective field theory beyond the Standard Model, at next-to-leading order in QCD. We parametrize new physics effects using dimension-six operators, and consider all…