Flavor-changing neutral Higgs boson couplings and top-quark–charm-quark production at the Next Linear Collider

Lin, Guey-Lin; Yi, C.

doi:10.1103/physrevd.56.7434

Cited by 33 publications

(12 citation statements)

References 11 publications

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“…An interesting feature of these reactions is that, being t-channel fusion processes, their cross sections grow with energy unlike s-channel reactions e + e − → tc which are suppressed at high energies. The cross sections of e + e − → tcν eνe and e + e − → tce + e − are found to be one or two orders of magnitude bigger than the cross sections of e + e − → tc [54,55]. In the present study, we limit ourself to e + e − colliders, its γγ option and muon colliders.…”

Section: φ →Tcmentioning

confidence: 87%

Top and Higgs flavor changing neutral couplings in two Higgs doublets model

Arhrib

2005

Phys. Rev. D

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We study various channels of top and Higgs Flavor Changing Neutral Couplings (FCNC) in the two Higgs doublet Model with natural flavor conservation (2HDM-I and 2HDM-II). We update known results about t → cγ , cZ , cg and comment on t → ch 0 . The decays t → ch 0 as well as {h 0 , H 0 } →tc are sensitive both to the bottom Yukawa coupling as well as to the trilinear scalar couplings h 0 H + H − and H 0 H + H − . After imposing unitarity constraints as well as vacuum stability conditions on scalar sector parameters, in 2HDM-II we found that for large tan β > ∼ 40 and rather light charged Higgs mass M H± < ∼ 150 GeV, the maximum values allowed for Br(t → ch 0 ), Br(H 0 →tc) and Br(h 0 →tc) are: 8 × 10 −5 , 10 −3 and 10 −4 respectively. For charged Higgs mass in the range [200, 300] GeV, which can accommodate B → X s γ constraint if one takes into account large theoretical uncertainties, the branching ratio of both H 0 →tc and h 0 →tc can still be slightly larger than 10 −5 . For A 0 →tc, its branching ratio is smaller than ≈ 10 −7 in both 2HDM-I and 2HDM-II. We study also the top-charm associated production at e + e − colliders and its γγ option as well as at muon colliders. It is found that the cross section of γγ →tc can be of the order 0.01 → 0.1 fb near threshold region, while the cross section of e + e − →tc is well below 10 −2 fb. The situation is slightly better for muon colliders where a few fb cross section can be reached for large tan β and low center of mass energy √ s < ∼ 500GeV.

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Section: φ →Tcmentioning

confidence: 87%

Top and Higgs flavor changing neutral couplings in two Higgs doublets model

Arhrib

2005

Phys. Rev. D

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“…mechanism [15][16][17][18]. 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][6...…”

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, the rates enhanced by the presence of new physics such as SUSY, topcolor-assisted technicolor or extended Higgs sector [11] may reach observable rates in some cases, and can then be used to probe FCNC couplings. Single top production can also proceed through the introduction of anomalous couplings: t-q-g, t-q-γ and t-q-Z [12] at both hadron and e + e − colliders.…”

Section: Introductionmentioning

confidence: 99%

Single top quark production in flavor-changingZ′models

et al. 2006

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In some models with an extra U (1) gauge boson Z ′ , the gauge couplings of the Z ′ to different generations of fermions may not be universal. Flavor mixing in general can be induced at the tree level in the up-type and/or down-type quark sector after diagonalizing their mass matrices. In this work, we concentrate on the flavor mixing in the up-type quark sector. We deduce a constraint from D 0 − D 0 mixing. We study in detail single top-quark production via flavor-changing Z ′ exchange at the LHC and the ILC. We found that for a typical value of M Z ′ = 1 TeV, the production cross section at the LHC can be of the order of 1 fb. However, the background from the Standard Model single top-quark production makes it difficult to detect the flavor-changing Z ′ signal unless with a decent charm tagging method. On the other hand, at the ILC, the production cross section at the resonance energy of √ s ≈ M Z ′ can reach a size of more than 100 fb. Even away from the resonance, the cross section at ILC is shown to be larger than the threshold of observability of 0.01 fb.

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Flavor-changing neutral Higgs boson couplings and top-quark–charm-quark production at the Next Linear Collider

Cited by 33 publications

References 11 publications

Top and Higgs flavor changing neutral couplings in two Higgs doublets model

Top and Higgs flavor changing neutral couplings in two Higgs doublets model

Enhancing thj production from top-Higgs FCNC couplings

Single top quark production in flavor-changingZ′models

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