Super-super leading logarithms

by Jack Holguin, Dr Jack Holguin (The University of Manchester)

Monday 1 Dec 2025, 16:00 → 18:00 Europe/Zurich

4/2-037 - TH meeting room (CERN)

In this seminar, I will demonstrate that the cumulative distribution of the event-shape observable one-jettiness (τ₁) in colour-singlet + jet production at hadron colliders receives a factorisation-breaking term of order αₛ⁴ ln⁶(1/τ₁) relative to the Born process. I will lead into this discussion by recapping developments in the understanding of factorisation breaking and super-leading logarithms in the gaps-between-jets observable, and by discussing the origin of factorisation breaking as a breakdown of QCD coherence in the initial state via Coulomb/Glauber gluon exchange. The factorisation-breaking logarithms in one-jettiness are one power higher than the previously identified super-leading logs; nevertheless, no new poles appear. Consequently, I argue that the usual factorisation of parton distribution functions at the scale μ ≈ τ₁ Q remains valid. I will also comment on the colour structure of the one-jettiness super-super-leading logarithm, hinting at its resummation.