Measuring single-top-associated Higgs production at the HL-LHC

TL;DR

This paper investigates the CP properties of the top-Yukawa coupling through Higgs production measurements at the HL-LHC, emphasizing the importance of disentangling single- and di-top-associated production for improved constraints.

Contribution

It introduces a novel analysis strategy for measuring tH production at the HL-LHC that does not assume the Higgs CP nature, enhancing the precision of CP property constraints.

Findings

Disentangling single- and di-top Higgs production tightens CP constraints.

All relevant Higgs measurements are used to constrain the top-Yukawa coupling.

Proposed method enables CP measurement without prior assumptions.

Abstract

Precision measurements of top-associated Higgs production are an important ingredient to unravel the $\mathcal{CP}$ nature of the Higgs boson. In this work, we constraint the $\mathcal{CP}$ nature of the top-Yukawa coupling taking into account all relevant inclusive and differential Higgs boson measurements. Based upon this fit, we show that it is crucial to disentangle single- and di-top-associated Higgs production for tightening indirect constraints on a $\mathcal{CP}$-odd top-Yukawa coupling in the future. In this context, we propose an analysis strategy for measuring $tH$ production at the HL-LHC without relying on assumptions about the Higgs $\mathcal{CP}$ character.