Higgs Bosons from Top Quark Decays

Abstract

In light of the discovery of a Standard Model (SM)-like Higgs boson ($h$) at the LHC, we investigate the top quark to Higgs boson transition $t\to W^{\ast }bh$, which is the leading $t\to h$ decay mode in the SM. We find the decay branching fraction to be $1.80\times 10^{-9}$. In comparison, the two-body, loop-induced $t\to ch$ transition occurs at $\sim 10^{-14}$ in the SM. We consider the consequences of gauge invariant dimension-6 operators affecting the $t\bar{t}h$ interaction and find that the decay branching fraction may be increased by a factor of two within current constraints on the coupling parameters from collider experiments. We also extend the calculation to the CP-conserving Type I and Type II Two Higgs Doublet Models (2HDM), including both CP-even and CP-odd Higgs bosons. For neutral scalar masses at about $100$ GeV, the decay rates can be several times larger than the SM result in the allowed range of model parameters. Observation prospects at present and future colliders are briefly addressed.

26 pages, 8 figures. Updated to match published version

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Cited by in corpus (10)

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• Enhanced $thj$ signal at the LHC with $h\to \gamma \gamma$ decay and $\mathcal{C}\mathcal{P}$-violating top-Higgs coupling
• Rare and exclusive few-body decays of the Higgs, Z, W bosons, and the top quark
• Probing the top-Higgs boson FCNC couplings via the $h\to \gamma \gamma$ channel at the HE-LHC and FCC-hh
• Searches for top-Higgs FCNC couplings via the Whj signal with $h\to \gamma \gamma$ at the LHC
• Searches for anomalous $tqZ$ couplings from the trilepton signal of $tZ$ associated production at the 14 TeV LHC
• Searches for the FCNC couplings from top-Higgs associated production signal with $h\to \gamma \gamma$ at the LHC
• Probing anomalous top-Higgs couplings at the HL-LHC via $H\to W{W}^{\ast }$ decay channels
• Lepton pair emission in the top quark decay $t\to b{W}^{+}{\ell }^{-}{\ell }^{+}$