Direct Higgs-top CP-phase measurement with t(t)over-barh at the 14TeV LHC and 100TeV FCC

The study of the Higgs boson's properties is a cornerstone of the LHC and future collider programs. In this paper, we examine the potential to directly probe the Higgs-top interaction strength and CP-structure in the t (t) over barh channel with the Higgs boson decaying to bottom-quark pairs and top-quarks in the di-leptonic mode. We adopt the BDRS algorithm to tag the boosted Higgs and exploit the M-2-assisted reconstruction to compute observables sensitive to the CP-phase at the t (t) over bar rest frame, where the new physics sensitivity can be enhanced. Performing a side-band analysis at the LHC to control the continuum t (t) over barb (b) over bar background, we find that the Higgs-top strength and CP-phase can be probed up to delta(kappa t) less than or similar to 20% and |alpha| less than or similar to 36 degrees at 95% CL, respectively. We also derive that a similar analysis at a 100TeV future collider could further improve the precision to delta(kappa t) less than or similar to 1% and |alpha| less than or similar to 1.5 degrees, where the CP-odd observables play a crucial role, boosting the sensitivity on the CP-phase.

Automated summary

This paper explores the properties of the Higgs boson in the t(t)barh channel and discusses the potential to study the strength of the Higgs-top quark interaction and CP structure in the LHC and future colliders. By performing side-band analysis and using specific algorithms, we are able to enhance the sensitivity to the Higgs-top strength and CP phase.