New Physics Effects in the Flavor-Changing Neutral Couplings of the Top Quark

Larios, F.; Martı́nez, R.; Pérez, M. A.

doi:10.1142/s0217751x06033039

Cited by 70 publications

(47 citation statements)

References 115 publications

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“…In the Higgs basis the doublets are given by eqs. (220), where G ± and G 0 are the three 'would-be Goldstone bosons' while H ± are the two physical charged scalars. The three physical neutral scalars S 1,2,3 are the linear combinations of H, R, and I given by eq.…”

Section: A Minimal Realistic Model With Spontaneous Cp Violationmentioning

confidence: 99%

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Theory and phenomenology of two-Higgs-doublet models

et al. 2012

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We discuss theoretical and phenomenological aspects of two-Higgs-doublet extensions of the Standard Model. In general, these extensions have scalar mediated flavour changing neutral currents which are strongly constrained by experiment. Various strategies are discussed to control these flavour changing scalar currents and their phenomenological consequences are analysed. In particular, scenarios with natural flavour conservation are investigated, including the so-called type I and type * E-mail: gbranco@ist.utl.pt † E-mail: ferreira@cii.fc.ul.pt ‡ E-mail: balio@cftp.ist.utl.pt § E-mail: rebelo@ist.utl.pt ¶ E-mail: mtsher@wm.edu E-mail: jpsilva@cftp.ist.utl.pt 1 II models as well as lepton-specific and inert models. Type III models are then discussed, where scalar flavour changing neutral currents are present at tree level, but are suppressed by either specific ansatze for the Yukawa couplings or by the introduction of family symmetries leading to a natural suppression mechanism. We also consider the phenomenology of charged scalars in these models. Next we turn to the role of symmetries in the scalar sector. We discuss the six symmetry-constrained scalar potentials and their extension into the fermion sector. The vacuum structure of the scalar potential is analysed, including a study of the vacuum stability conditions on the potential and the renormalization-group improvement of these conditions is also presented. The stability of the tree level minimum of the scalar potential in connection with electric charge conservation and its behaviour under CP is analysed. The question of CP violation is addressed in detail, including the cases of explicit CP violation and spontaneous CP violation. We present a detailed study of weak basis invariants which are odd under CP. These invariants allow for the possibility of studying the CP properties of any two-Higgs-doublet model in an arbitrary Higgs basis. A careful study of spontaneous CP violation is presented, including an analysis of the conditions which have to be satisfied in order for a vacuum to violate CP. We present minimal models of CP violation where the vacuum phase is sufficient to generate a complex CKM matrix, which is at present a requirement for any realistic model of spontaneous CP violation.

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Section: A Minimal Realistic Model With Spontaneous Cp Violationmentioning

confidence: 99%

“…Direct bounds on λ tc can be obtained from t → ch, which was first discussed by Hou [209] and much more recently in Refs. [219,220,221]. For a Higgs mass of 120 GeV, the branching ratio is roughly 0.005 λ 2 ct .…”

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confidence: 98%

Theory and phenomenology of two-Higgs-doublet models

et al. 2012

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“…But they can be greatly enhanced by the extended flavor structures in many new physics models, for example the minimal supersymmetric model (MSSM) with/without R-parity [19][20][21][22][23][24][25][26][27][28][29][30][31][32], two-Higgsdoublet model (2HDM) type-III [33][34][35][36][37][38][39][40][41][42][43][44][45], and the other miscellaneous models [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60]. So the study of top-Higgs FCNC interactions is a common interest of the theory and experiment communities [61][62][63][64][65][66][67]. …”

Section: Introductionmentioning

confidence: 99%

Enhancing thj production from top-Higgs FCNC couplings

2015

J. High Energ. Phys.

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Abstract:In this paper, we study the single top and Higgs associated production pp → thj in the presence of top-Higgs FCNC couplings at the LHC. Under the current constraints, we find that the full cross section of pp → thj can be sizably enhanced in comparison with the SM predictions at 8 and 14 TeV LHC. We further explore the observability of top-Higgs FCNC couplings through pp → t(→ b + ν )h(→ γγ)j and find that the branching ratios Br(t → qh), Br(t → uh) and Br(t → ch) can be respectively probed to 0.12%, 0.23% and 0.26% at 3σ sensitivity at 14 TeV LHC with L = 3000 fb −1 .

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“…However, some new physics models can enhance these branching ratios significantly [106][107][108]. So rare top decays offer an opportunity to test the SM and search for new physics effects.…”

Section: Jhep04(2014)170mentioning

confidence: 99%

Light axigluon and single top production at the LHC

Yue

Cao

Zeng

2014

J. High Energ. Phys.

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The light axigluon model can explain the Tevatron tt forward-backward asymmetry and at the same time satisfy the constraints from the electroweak precision measurement and the AT LAS and CM S data, which induces the flavor changing (F C) couplings of axigluon with the SM and new quarks. We investigate the effects of these F C couplings on the s-and t-channel single top productions at the LHC and the F C decays Z → bs+bs, t → cγ and cg. Our numerical results show that the light axigluon can give significantly contributions to single top production and the rare top decays t → cγ and cg.

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New Physics Effects in the Flavor-Changing Neutral Couplings of the Top Quark

Cited by 70 publications

References 115 publications

Theory and phenomenology of two-Higgs-doublet models

Theory and phenomenology of two-Higgs-doublet models

Enhancing thj production from top-Higgs FCNC couplings

Light axigluon and single top production at the LHC

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