Framing energetic top-quark pair production at the LHC

Understand

Top-quark pair production is central to many facets of LHC physics.

• At leading order, the top and anti-top are produced in a back-to-back topology, however this topology accounts only for a minority of $t \bar t$ events with TeV-scale momentum transfer.
• The remaining events instead involve the splitting of an initial or final-state gluon to $t \bar t$.
• We provide simple quantitative arguments that explain why this is the case and examine the interplay between different topologies and a range of variables that characterise the event hardness.