$CP$ Properties of Higgs Boson Interactions with Top Quarks in the $t\bar{t}H$ and $tH$ Processes Using $H \rightarrow \gamma\gamma$ with the ATLAS Detector

Understand

A study of the $CP$ properties of the interaction between the Higgs boson and top quarks is presented.

• Higgs bosons are identified via the diphoton decay channel ($H \rightarrow \gamma\gamma$) and their production in association with a top quark pair ($t\bar{t}H$) or single top quark ($tH$) is studied.
• The analysis uses 139 fb$^{-1}$ of proton-proton collision data recorded at a center-of-mass energy of $\sqrt{s}$ = 13 TeV with the ATLAS detector at the Large Hadron Collider.
• Assuming a $CP$-even coupling, the $t\bar{t}H$ process is observed with a significance of 5.2 standard deviations.