NNLO beam functions for angularity distributions

Guido Bell; Kevin Brune; Goutam Das; Marcel Wald

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arXiv · 2409.13348

NNLO beam functions for angularity distributions

Guido Bell·Kevin Brune·Goutam Das·Marcel Wald

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Abstract

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.

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Guido Bell, Kevin Brune, Goutam Das, Marcel Wald. 2024-09-20. NNLO beam functions for angularity distributions. https://arxiv.org/abs/2409.13348

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