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Tests of the Lorentz structure of t --> W b decay will be carried out at the Tevatron, and later at the LHC and at a NLC. To quantitatively assay future measurements of competing observables, we consider the (V-A) coupling values of the…

High Energy Physics - Phenomenology · Physics 2012-08-27 Charles A. Nelson , L. J. Adler,

To quantitatively assay future measurements of competing observables in t --> W b decay, we consider the g_{V-A} coupling values of the helicity decay parameters versus those for "(V-A)+ Single Additional Lorentz Structures". There are 2…

High Energy Physics - Phenomenology · Physics 2007-05-23 Charles A. Nelson

To enable an evaluation of future measurements of the helicity parameters for " t --> W b " decay in regard to " T_FS violation", this paper considers the effects of an additional pure-imaginary coupling, (i g/2 Lambda) or (i g), associated…

High Energy Physics - Phenomenology · Physics 2012-08-27 Charles A. Nelson , L. J. Adler,

This talk concerns some theoretical patterns of the helicity amplitudes for t --> W b decay. The patterns involve both the standard model's four decay helicity amplitudes, A_{SM}, and also the amplitudes A_{+} in the case of an additional…

High Energy Physics - Phenomenology · Physics 2007-05-23 Charles A. Nelson

The most general Lorentz-invariant decay-density-matrix for $t\to W^{+}b\to (l^{+}\nu)b$, or for $t\to W^{+}b\to (j_{\bar d}j_u)b$, is expressed in terms of eight helicity parameters. The parameters are physically defined in terms of…

High Energy Physics - Phenomenology · Physics 2009-10-30 Charles A. Nelson , Brian T. Kress , Marco Lopes , Thomas P. McCauley

In the standard model, for the t --> W b decay mode, the relative phase is 0-degrees between the dominant A(0,-1/2) and A(-1, -1/2) helicity amplitudes. However, in the case of an additional large t_R --> b_L chiral weak-transition moment,…

High Energy Physics - Phenomenology · Physics 2008-10-09 Charles A. Nelson

Due to the absence of hadronization effects and the large top mass, top quark decay will be uniquely sensitive to fundamental electroweak physics at the Tevatron, at the LHC, and at a future linear collider. A complete measurement of the…

High Energy Physics - Phenomenology · Physics 2009-01-07 Charles A. Nelson

For the observed t --> W b decay, an intensity-ratio equivalence-theorem for two Lorentz-invariant couplings is shown to be related to symmetries of tWb-transformations. Three explicit tWb-transformations, A_{+}=M A_{SM}, ... relate the…

High Energy Physics - Phenomenology · Physics 2007-05-23 Charles A. Nelson

For the " t --> W b " decay mode, an intensity-ratio equivalence-theorem for two Lorentz-invariant couplings is shown to be related to symmetries of tWb-transformations. Explicit tWb-transformations, A_{+}=M A_{SM}, P A_{SM}, B A_{SM}…

High Energy Physics - Phenomenology · Physics 2007-05-23 Charles A. Nelson

The modularity property of the helicity formalism is used to provide amplitude expressions and stage-two spin-correlation functions which can easily be used in direct experimental searches for electro-weak symmetries and dynamics in the…

High Energy Physics - Phenomenology · Physics 2009-10-30 Charles A. Nelson , Brian T. Kress , Marco Lopes , Thomas P. McCauley

The combination of the latest and most precise measurements of several top quark properties is presented in this paper in order to establish allowed regions on anomalous contributions to the Lorentz structure of the $Wtb$ vertex. These…

High Energy Physics - Phenomenology · Physics 2019-03-25 Frédéric Déliot , Miguel C. N. Fiolhais , António Onofre

For the t --> W b decay mode, an intensity-ratio equivalence for two distinct Lorentz-invariant couplings is shown to be a consequence of symmetries of tWb-transformations. Three explicit tWb-transformations connect the four standard…

High Energy Physics - Phenomenology · Physics 2007-05-23 Charles A. Nelson

The latest results on top quark physics, namely single top quark production cross sections, $W$-boson helicity and asymmetry measurements are used to probe the Lorentz structure of the $Wtb$ vertex. The increase of sensitivity to new…

We investigate several quantities, defined in the decays of top quark pairs, which can be used to explore non-standard Wtb interactions. Two new angular asymmetries are introduced in the leptonic decay of top (anti)quarks. Both are very…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. A. Aguilar-Saavedra , J. Carvalho , N. Castro , A. Onofre , F. Veloso

We study the sensitivity of the ATLAS experiment to Wtb anomalous couplings in top pair production with semileptonic decay, pp -> t tbar -> W+ b W- bbar, with one of the W bosons decaying leptonically and the other hadronically. Several…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. A. Aguilar-Saavedra , J. Carvalho , N. Castro , A. Onofre , F. Veloso

Measurements of several top-quark properties, obtained from the CMS data collected in 2011 and 2012 at centre-of-mass energies of 7 and 8 TeV are presented. The results include measurements of the top pair charge asymmetry, the W helicity…

High Energy Physics - Experiment · Physics 2019-08-14 Efe Yazgan

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…

High Energy Physics - Experiment · Physics 2016-04-12 ATLAS Collaboration

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…

High Energy Physics - Phenomenology · Physics 2010-12-13 Chuan-Ren Chen , F. Larios , C. -P. Yuan

Versus the standard model's t --> W b decay helicity amplitudes, three numerical puzzles occur at the 0.1 % level when one considers the amplitudes in the case of an additional (f_M + f_E) coupling of relative strength 53 GeV. The puzzles…

High Energy Physics - Phenomenology · Physics 2011-03-23 Charles A. Nelson

Due to the large production cross-section, many of the top quark properties can be measured very precisely at the LHC. A very few recent results, probed only through the top quark decay vertices are presented here. These results are based…

High Energy Physics - Experiment · Physics 2017-10-13 Prolay Kumar Mal
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