Direct Higgs-top CP-phase measurement with $$ t\overline{t}h $$ at the 14 TeV LHC and 100 TeV FCC
Dorival Gonçalves, Jeong Han Kim, Kyoungchul Kong, Yongcheng Wu
Abstract
A bstract 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 $$ t\overline{t}h $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>h</mml:mi> </mml:math> 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 $$ t\overline{t} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> rest frame, where the new physics sensitivity can be enhanced. Performing a side-band analysis at the LHC to control the continuum $$ t\overline{t}b\overline{b} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>t</mml:mi> <mml:mover> <mml:mi>t</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>b</mml:mi> <mml:mover> <mml:mi>b</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> background, we find that the Higgs-top strength and CP-phase can be probed up to $$ {\delta}_{\kappa_t} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>δ</mml:mi> <mml:msub> <mml:mi>κ</mml:mi> <mml:mi>t</mml:mi> </mml:msub> </mml:msub> </mml:math> ≲ 20% and | α | ≲ 36° at 95% CL, respectively. We also derive that a similar analysis at a 100 TeV future collider could further improve the precision to $$ {\delta}_{\kappa_t} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>δ</mml:mi> <mml:msub> <mml:mi>κ</mml:mi> <mml:mi>t</mml:mi> </mml:msub> </mml:msub> </mml:math> ≲ 1% and | α | ≲ 1 . 5°, where the CP-odd observables play a crucial role, boosting the sensitivity on the CP-phase.