NLL Resummation of Recoil-Sensitive Angularities Using SCET

Abstract

Jet angularities are a class of event shapes that are designed to measure the energy flow into angular regions of phase space between energetic jets. Angularity description relies on a free parameter b ($b > -1$) such that varying the exponent b changes the sensitivity of the observable to the substructure of the jet. For angularities measured relative to the thrust axis, the observable is sensitive to the recoil of collinear parton due to soft radiation when b is close to 0, while for $b \rightarrow 1$ recoil is power suppressed. Based on the unified framework of SCET$_\textrm{II}$, we discuss the key one-loop results for jet angularity distributions and present the renormalization group structure for $b<0$ angularities.