Enhancing thj production from top-Higgs FCNC couplings

Wu, Lei

doi:10.1007/jhep02(2015)061

Cited by 41 publications

(21 citation statements)

References 112 publications

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“…Combining the analysis of the different Higgs decay channels, based at √ s = 8 TeV and an integrated luminosity of 20.3 (19.7) fb −1 , the 95% CL upper limits obtained by ATLAS (CMS) [10,12] are Br(t → cH) ≤ 4.6(4.0) × 10 −3 and Br(t → uH) ≤ 4.5(5.5) × 10 −3 . On the phenomenological side the sensitivity of LHC measurements to these non-standard flavor violating couplings in the top sector has been explored in great details, considering (a) the top quark pair production [13][14][15][16], (b) the single top + Higgs production [3,17] and (c) single top + W production [18]. The analysis of the tqH coupling has also been carried out in the context of the next generation e − e + linear colliders, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) [19,20].…”

Section: Jhep01(2017)048mentioning

confidence: 99%

Exploring the top-Higgs FCNC couplings at polarized linear colliders with top spin observables

Melić¹,

Patra²

2017

J. High Energ. Phys.

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Abstract:We study the nature of flavor changing neutral couplings of the top quark with the Higgs boson and the up/charm quark in the tt production at linear colliders. There are previous bounds on such tqH couplings at both, linear and hadronic colliders, with the assumption that the top couples equally to the left and the right handed fermions. In this paper we examine chirality of the tqH coupling and construct different observables which will be sensitive to it. The kinematics of the emitted q from t → qH in tt production is discussed and it was found that the polar angle distribution of q is sensitive to the chiral nature of tqH couplings. The observables in the context of top-antitop spin correlations, which are sensitive to new physics in the top decay are considered using different spinquantization bases. It was found that in particular the off-diagonal basis can be useful to distinguish among the chiral tqH couplings. The sensitivity of the unpolarized ILC in probing the couplings at the 3σ level at √ s = 500 GeV and L = 500 fb −1 is also studied, resulting in predicted BR(t → qH) < 1.19 × 10 −3 . This limit is further improved to BR(t → qH) < 8.84 × 10 −4 with the inclusion of initial beam polarization of left handed electrons and right handed positrons.

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Section: Jhep01(2017)048mentioning

confidence: 99%

Exploring the top-Higgs FCNC couplings at polarized linear colliders with top spin observables

Melić¹,

Patra²

2017

J. High Energ. Phys.

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“…The experimental search for top quark FCNC can be performed either by anomalous decays or production of top quarks at hadron colliders with top quark FCNC couplings [59][60][61][62][63][64]. We note that the searches for t → ch [65,66] do not provide any constraints on 2HDM type III in alignment limit since the top quark FCNC couplings with the SM Higgs vanish.…”

Section: Jhep12(2015)038mentioning

confidence: 99%

Exploring top quark FCNC within 2HDM type III in association with flavor physics

Kim

Yoon

Yuan

2015

J. High Energ. Phys.

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Abstract:The top quark flavor changing neutral current (FCNC) process is an excellent probe to search for new physics in top sector since the Standard Model expectation is extremely suppressed. We explore Higgs-mediated top quark FCNC, focusing on H-tc Yukawa coupling λ ct within the general two Higgs doublet model. After electroweak symmetry breaking the top quark FCNC couplings are included in the charged Higgs Yukawa sector so that they contribute to various processes in flavor physics. To probe λ ct , we study anomalous single top production and the same sign top pair production at the LHC in association with flavor physics from the tree-level processes B → D ( * ) τ ν, B → τ ν as well as from the loop-level processes B d → X s γ, B d,s − B d,s mixing. We perform combined analysis of all the constraints regarding the fine-tuning argument to fit the data and discuss future prospect. The recently updated measurements on B → D ( * ) τ ν still prefer large λ ct , but we show that the current bound on the same sign top pair production at the LHC gives the most significant upper bound on λ ct to be less than 10 ∼ 30 depending on neutral heavy Higgs masses. We also find that for the given upper bound on λ ct , B → D ( * ) τ ν put significant lower bound on H-τ -τ Yukawa coupling, and the bound is proportional to the charged Higgs mass.

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“…The gluino-loop gives the dominant contribution to B(t → q h) that generically is of the order α s /4π ≈ 0.01, which is by an order of magnitude less than the current bound, but probably within LHC's projected reach at √ s = 14 TeV with 3000 fb −1 [23] (see also note [24] There are already many phenomenological studies for these decays, a partial list included in [25][26][27][28][29][30][31][32]. Very recently in [33,34], plausible techniques that distinguish between t → u h and t → c h have been suggested. It is therefore worth looking for MSSM branching fraction predictions from both rare top decays, t → u h and t → c h.…”

Section: Introductionmentioning

confidence: 99%

Rare top-quark decays to Higgs boson in the MSSM

Suxho¹

2016

Proceedings of 18th International Conference From the Planck Scale to the Electroweak Scale — PoS(PLANCK 2015)

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In full one-loop generality and in next-to-leading order in QCD, we study rare top to Higgs boson flavour changing decay processes t → q h with q = u, c quarks, in the general MSSM with R-parity conservation. Our primary goal is to search for enhanced effects on B(t → q h) that could be visible at current and high luminosity LHC running. To this end, we perform an analytical expansion of the amplitude in terms of flavour changing squark mass insertions that treats both cases of hierarchical and degenerate squark masses in a unified way. We identify two enhanced effects allowed by various constraints: one from holomorphic trilinear soft SUSY breaking terms and/or right handed up squark mass insertions and another from non-holomorphic trilinear soft SUSY breaking terms and light Higgs boson masses. Interestingly, even with O(1) flavour violating effects in the, presently unconstrained, up-squark sector, SUSY effects on B(t → q h) come out to be unobservable at LHC mainly due to leading order cancellations between penguin and self energy diagrams and the constraints from charge-and colour-breaking minima (CCB) of the MSSM vacuum. An exception to this conclusion may be effects arising from non-holomorphic soft SUSY breaking terms in the region where the CP-odd Higgs mass is smaller than the top-quark mass but this scenario is disfavoured by recent LHC searches. Our calculations for t → q h decay are made available in SUSY FLAVOUR numerical library. *

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Enhancing thj production from top-Higgs FCNC couplings

Cited by 41 publications

References 112 publications

Exploring the top-Higgs FCNC couplings at polarized linear colliders with top spin observables

Exploring the top-Higgs FCNC couplings at polarized linear colliders with top spin observables

Exploring top quark FCNC within 2HDM type III in association with flavor physics

Rare top-quark decays to Higgs boson in the MSSM

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