Direct Higgs-top CP-phase measurement with $$ t\overline{t}h $$ at the 14 TeV LHC and 100 TeV FCC

Gonçalves, Dorival; Kim, Jeong Han; Kong, Kyoungchul; Wu, Y.

doi:10.1007/jhep01(2022)158

Cited by 23 publications

(16 citation statements)

References 56 publications

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“…As discussed in Refs. [18,19], top quark reconstruction in the dilepton channel plays an important role. For example, Table 1 shows that the endpoints method gives 74.2% efficiency and 87.4% purity at detector-level (marked as # in Fig.…”

Section: Discussion and Outlookmentioning

confidence: 99%

“…6), which is comparable to results presented in Refs. [18,19]. Using the M 2 reconstruction and the sideband subtraction, the uncertainty (δκ t ) on the top quark Yukawa coupling (κ t = y t /y t,SM , which is the deviation from the SM value) is calculated as δκ t ∼ 0.096 [19] at the HL-LHC.…”

Section: Discussion and Outlookmentioning

confidence: 99%

“…[18,19]. Using the M 2 reconstruction and the sideband subtraction, the uncertainty (δκ t ) on the top quark Yukawa coupling (κ t = y t /y t,SM , which is the deviation from the SM value) is calculated as δκ t ∼ 0.096 [19] at the HL-LHC. On the other hand, our results show that the same purity (87.4%) can be obtained at a higher efficiency using DNN (with 92% efficiency) and LBN (with nearly 100% efficiency), which would lead to a gain of 24% and 35% more events, respectively.…”

Section: Discussion and Outlookmentioning

confidence: 99%

“…Following more accurate procedure in Ref. [19], we estimate the uncertainty to be reduced to δκ t ∼ 0.086 and δκ t ∼ 0.082 using DNN and LBN, respectively.…”

Section: Discussion and Outlookmentioning

confidence: 99%

“…For example, Refs. [18][19][20] aim to measure the Yukawa coupling and the CP-phase in the Top-Higgs interaction via t th production in the dilepton channel, utilizing the kinematic methods proposed in Refs. [1,21].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Resolving Combinatorial Ambiguities in Dilepton $t \bar t$ Event Topologies with Neural Networks

Alhazmi,

Dong,

Huang

et al. 2022

Preprint

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We study the potential of deep learning to resolve the combinatorial problem in SUSYlike events with two invisible particles at the LHC. As a concrete example, we focus on dileptonic t t events, where the combinatorial problem becomes an issue of binary classification: pairing the correct lepton with each b quark coming from the decays of the tops. We investigate the performance of a number of machine learning algorithms, including attention-based networks, which have been usedfor a similar problem in the fully-hadronic channel of t t production; and the Lorentz Boost Network, which is motivated by physics principles. We then consider the general case when the underlying mass spectrum is unknown, and hence no kinematic endpoint information is available. Compared against existing methods based on kinematic variables, we demonstrate that the efficiency for selecting the correct pairing is greatly improved by utilizing deep learning techniques.

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Section: Discussion and Outlookmentioning

confidence: 99%

Section: Discussion and Outlookmentioning

confidence: 99%

Section: Discussion and Outlookmentioning

confidence: 99%

“…Following more accurate procedure in Ref. [19], we estimate the uncertainty to be reduced to δκ t ∼ 0.086 and δκ t ∼ 0.082 using DNN and LBN, respectively.…”

Section: Discussion and Outlookmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Resolving Combinatorial Ambiguities in Dilepton $t \bar t$ Event Topologies with Neural Networks

Alhazmi,

Dong,

Huang

et al. 2022

Preprint

Self Cite

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Constraining $$ \mathcal{CP} $$-violation in the Higgs-top-quark interaction using machine-learning-based inference

Bahl

Braß

2022

J. High Energ. Phys.

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While $$ \mathcal{CP} $$ CP violation in the Higgs interactions with massive vector boson is already tightly constrained, the $$ \mathcal{CP} $$ CP nature of the Higgs interactions with fermions is far less constrained. In this work, we assess the potential of machine-learning-based inference methods to constrain $$ \mathcal{CP} $$ CP violation in the Higgs top-Yukawa coupling. This approach enables the use of the full available kinematic information. Concentrating on top-associated Higgs production with the Higgs decaying to two photons, we derive expected exclusion bounds for the LHC and the high-luminosity phase of the LHC. We also study the dependence of these bounds on the Higgs interaction with massive vector bosons and their robustness against theoretical uncertainties. In addition to deriving expected exclusion bounds, we discuss at which level a non-zero $$ \mathcal{CP} $$ CP -violating top-Yukawa coupling can be distinguished from the SM. Moreover, we analyze which kinematic distributions are most sensitive to a $$ \mathcal{CP} $$ CP -violating top-Yukawa coupling.

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Probing the CP structure of the top quark Yukawa at the future muon collider

Cassidy,

Dong,

Kong

et al. 2024

J. High Energ. Phys.

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We study the top-Higgs coupling with a CP violating phase ξ at a future multi-TeV muon collider. We focus on processes that are directly sensitive to the top quark Yukawa coupling: $$ t\overline{t}h $$ t t ¯ h , tbhμν, and $$ t\overline{t} h\nu \overline{\nu} $$ t t ¯ hν ν ¯ with $$ h\to b\overline{b} $$ h → b b ¯ and semileptonic top decays. At different energies, different processes dominate the cross section, providing complementary information. At and above an energy of $$ \mathcal{O}(10) $$ O 10 TeV, vector boson fusion processes dominate. As we show, in the Standard Model there is destructive interference in the vector boson fusion processes $$ t\overline{t} h\nu \overline{\nu} $$ t t ¯ hν ν ¯ and tbhμν between the top quark Yukawa and Higgs-gauge boson couplings. A CP-violating phase changes this interference, and the cross section measurement is very sensitive to the size of the CP-violating angle. Although we find that the cross sections are measured to $$ \mathcal{O}\left(50\%\right) $$ O 50 % statistical uncertainty at 1σ, a 10 and 30 TeV muon collider can bound the CP-violating angle |ξ| ≲ 9.0° and |ξ| ≲ 5.4°, respectively. However, cross section measurements are insensitive to the sign of the CP-violating angle. To determine that the coupling is truly CP violating, observables sensitive to CP-violation must be measured. We find in the $$ t\overline{t}h $$ t t ¯ h process the azimuthal angle between the $$ t+\overline{t} $$ t + t ¯ plane and the initial state muon+Higgs plane shows good discrimination for ξ = ±0.1π. For the tbhμν and $$ t\overline{t} h\nu \overline{\nu} $$ t t ¯ hν ν ¯ processes, the operator proportional to $$ \left({\overrightarrow{p}}_{\mu}\times {\overrightarrow{p}}_h\right) $$ p → μ × p → h · $$ {\overrightarrow{p}}_t $$ p → t is sensitive to the sign of CP phase ξ. From these observables, we construct asymmetry parameters that show good distinction between different values and signs of the CP violating angle.

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Direct Higgs-top CP-phase measurement with $$ t\overline{t}h $$ at the 14 TeV LHC and 100 TeV FCC

Cited by 23 publications

References 56 publications

Resolving Combinatorial Ambiguities in Dilepton $t \bar t$ Event Topologies with Neural Networks

Resolving Combinatorial Ambiguities in Dilepton $t \bar t$ Event Topologies with Neural Networks

Constraining $$ \mathcal{CP} $$-violation in the Higgs-top-quark interaction using machine-learning-based inference

Probing the CP structure of the top quark Yukawa at the future muon collider

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