Probing top-quark couplings indirectly at Higgs factories
(2018) Chinese Physics C : High Energy Physics and Nuclear Physics — Vol. 42, n° 12, p. 123107 (2018)
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- Abstract
- We perform a global effective-field-theory analysis to assess the combined precision of Higgs couplings, triple gauge-boson couplings, and top-quark couplings, at future circular e + e − colliders, with a focus on runs below the production threshold. Deviations in the top-quark sector entering as one-loop corrections are consistently taken into account in the Higgs and diboson processes. We find that future lepton colliders running at center-of-mass energies below the production threshold can still provide useful information on top-quark couplings, by measuring virtual top-quark effects. With rate and differential measurements, the indirect individual sensitivity achievable is better than at the high-luminosity LHC. However, strong correlations between the extracted top-quark and Higgs couplings are also present and lead to much weaker global constraints on top-quark couplings. This implies that a direct probe of top-quark couplings above the production threshold is also helpful for the determination of Higgs and triple-gauge-boson couplings. In addition, we find that below the production threshold, the top-quark Yukawa coupling can be determined by its loop corrections to all Higgs production and decay channels. Degeneracy with the ggh coupling can be resolved, and even a global limit is competitive with the prospects of a linear collider above the threshold. This provides an additional means of determining the top-quark Yukawa coupling indirectly at lepton colliders.
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Citations
Durieux, G., Gu, J., Vryonidou, E., & Zhang, C. (2018). Probing top-quark couplings indirectly at Higgs factories. Chinese Physics C : High Energy Physics and Nuclear Physics, 42(12), 123107. https://doi.org/10.1088/1674-1137/42/12/123107 (Original work published 2018)