Measurement of colour flow using jet-pull observables in $t\bar{t}$ events with the ATLAS experiment at $\sqrt{s} = 13$ TeV

Understand

Previous phenomenological studies and measurements have shown that weighted angular moments derived from jet constituents encode the colour connections between initiating partons that seed the jets.

• This paper presents measurements of two such distributions, the jet-pull angle and jet-pull magnitude, both of which are derived from the jet-pull angular moment.
• The measurement is performed in $t\bar{t}$ events with one leptonically decaying $W$ boson and one hadronically decaying $W$ boson, using $36.1$ fb$^{-1}$ of $pp$ collision data recorded by the ATLAS detector at $\sqrt{s} = 13$ TeV delivered by the Large Hadron Collider.
• The observables are measured for two dijet systems, corresponding to the colour-connected daughters of the $W$ boson and the two $b$-jets from the top-quark decays.