NNLO beam functions for angularity distributions

Journal of High Energy Physics, vol. 2025

Abstract

A bstract The popular class of angularity event shapes provides a wealth of information on the hadronic final-state distribution in collider events. While initially proposed for e + e − collisions, angularities have more recently attracted considerable interest as a jet substructure observable at hadron colliders. Moreover, angularities can be measured as a global event shape in deep inelastic electron-nucleon scattering (DIS), and the respective factorisation theorem contains a beam function that parametrises the collinear initial-state radiation. In the present work, we compute the quark and gluon beam functions for seven different angularities to next-to-next-to-leading order (NNLO) in the strong-coupling expansion. Our calculation is based on an automated framework that was previously developed for SCET-2 observables, and which we transfer in the current work to the generic SCET-1 case. Our results are relevant for resumming DIS angularity distributions at NNLL′ accuracy.

Authors 4

1. Guido Bell

   University of Siegen

   Affiliation as printed

   Universität Siegen

2. Kevin Brune

   University of Siegen

   Affiliation as printed

   Universität Siegen

3. Goutam Das corresponding Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University

4. Marcel Wald

   University of Siegen

   Affiliation as printed

   Universität Siegen