Dimension-six<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>CP</mml:mi></mml:math>-conserving operators of the third-family quarks and their effects on collider observables

Whisnant, K.; Yang, Jin Min; Young, Ben; Zhang, X.

doi:10.1103/physrevd.56.467

Cited by 131 publications

(115 citation statements)

References 18 publications

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“…It thus provides a probe of electroweak properties of the top quark. For example, one can study the Cabibbo-KobayashiMaskawa (CKM) matrix element V tb , new W -t-b couplings beyond the Standard Model (SM) [14,15,16,17,18,19,20,21,22,23,24,25], and CP violation [26,27,28] in single top quark production and decay. The angular correlations among the decay products of polarized top quarks also provide a useful handle on these couplings [29,30,31,32,33,34,35,36].…”

Section: Introductionmentioning

confidence: 99%

Next-to-leading order corrections to single top quark production and decay at the Fermilab Tevatron:s-channel process

2005

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We present a study of s-channel single top quark production at the upgraded Tevatron pp collider, including the next-to-leading order (NLO) QCD corrections to the production and decay of the top quark. The "modified" narrow width approximation was adopted to preserve the spin of the top quark in its production and decay. We discuss the effect of the different O(α s ) contributions on the inclusive cross section as well as various kinematical distributions after imposing the relevant cuts to select s-channel single top signal events. In particular the O(α s ) decay contribution, while small in size, has a significant impact on several distributions. With the help of the best-jet algorithm to reconstruct the top quark we demonstrate that it is possible to study kinematical and spin correlations in s-channel single top events. We furthermore compare top quark spin measurements in two different basis and show how NLO corrections have to be taken into consideration in searches for the Higgs boson through W ± H associated production at the Tevatron.

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Section: Introductionmentioning

confidence: 99%

Next-to-leading order corrections to single top quark production and decay at the Fermilab Tevatron:s-channel process

2005

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“…Results from the ATLAS and CMS experiments indicate that the W W h coupling is close to its SM value [1,2], and evidence suggest that the bbh coupling cannot be much larger than the SM prediction [35,36]. As dimension-six tW bh verticies originate from terms of the form tW b(v + h) [25,29], the size of anomalous 4-point tW bh couplings are restricted to be small by the stringent limits on anomalous tW b couplings [28,30,[37][38][39][40]. Anomalous htc/u couplings are constrained to be small [12,[41][42][43].…”

Section: A1 Eft Framework and Parametersmentioning

confidence: 99%

“…To systematically search for new physics beyond the reach of present-day experiments, we employ Effective Field Theory (EFT) to model new physical phenomena and linearly realize the SM gauge symmetries [24][25][26]. After integrating out heavy degrees of freedom at a scale Λ, the low energy effects can be parameterized by…”

Section: A the Sm As An Effective Field Theorymentioning

confidence: 99%

Higgs bosons from top quark decays

Han

Ruiz

2014

Phys. Rev. D

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In light of the discovery of a Standard Model (SM)-like Higgs boson (h) at the LHC, we investigate the top quark to Higgs boson transition t → W * bh, which is the leading t → h decay mode in the SM. We find the decay branching fraction to be 1.80 × 10 −9 . In comparison, the two-body, loop-induced t → ch transition occurs at ∼ 10 −14 in the SM. We consider the consequences of gauge invariant dimension-6 operators affecting the tth interaction and find that the decay branching fraction may be increased by a factor of two within current constraints on the coupling parameters from collider experiments. We also extend the calculation to the CP-conserving Type I and Type II Two Higgs Doublet Models (2HDM), including both CP-even and CP-odd Higgs bosons. For neutral scalar masses at about 100 GeV, the decay rates can be several times larger than the SM result in the allowed range of model parameters. Observation prospects at present and future colliders are briefly addressed.

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“…Assuming CP conservation and ignoring those operators which only lead to anomalous dipole-moment couplings which are suppressed, we have two dimension-six gauge invariant operators which give rise to anomalous right-handed Zbb coupling [9],…”

Section: The Operators and Their Induced Verticesmentioning

confidence: 99%

“…One can envisage in the scheme of a larger symmetry that encompasses the new physics, after integrating out the heavy degrees of freedom which lie outside the SM spectrum, higher dimensional terms will be present at energies not too far above the electroweak scale and the induced effective terms should preserve the basic SM structure. Then the new physics effects on the Zbb couplings can be parameterized by a set of higher dimensional operators [9,10] which are SU C (3) × SU L (2) × U Y (1) symmetric before the electroweak symmetry breaking becomes explicit. From the above argument we see that before the electroweak symmetry breaking, the Zbb part of the effective Lagrangian can take the general form…”

Section: Introductionmentioning

confidence: 99%

Implications of LEP and SLD data for new physics inZbb¯couplings

2000

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The combined LEP/SLD data on the bb forward-backward asymmetry from the Z-pole measurements may imply the presence of new physics in the Zbb couplings. In general, the effect of new physics can be parameterized byBy fitting the recently announced LEP/SLD data on A b and R b , the size of the coupling strengths of these operators can be determined. We also found that the new physics operators can be divided into two types, depending on their Higgs field content. The ones involving the Higgs have very mild effects at higher energy colliders, while the other type which do not contain the Higgs field can show significantly large effects on bb production at LEP II, tt production at the NLC and single top production at the Tevatron. The preliminary data from the LEP II measurements disfavors the second type of operators.

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Dimension-sixCP-conserving operators of the third-family quarks and their effects on collider observables

Cited by 131 publications

References 18 publications

Next-to-leading order corrections to single top quark production and decay at the Fermilab Tevatron:s-channel process

Next-to-leading order corrections to single top quark production and decay at the Fermilab Tevatron:s-channel process

Higgs bosons from top quark decays

Implications of LEP and SLD data for new physics inZbb¯couplings

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