Angularity in DIS at next-to-next-to-leading log accuracy

TL;DR

This paper introduces a systematic study of angularity event-shape observables in deep-inelastic scattering, providing factorization, a new beam function, and NNLL resummation for various parameter values.

Contribution

It defines angularity for DIS, derives a new angularity beam function at order αs, and performs NNLL resummation across a range of the parameter a.

Findings

Factorization valid for a below and above thrust region

New angularity beam function derived at order αs

Resummed predictions at NNLL accuracy for various a values

Abstract

Angularity is a class of event-shape observables that can be measured in deep-inelastic scattering. With its continuous parameter $a$ one can interpolate angularity between thrust and broadening and further access beyond the region. Providing such systematic way to access various observables makes angularity attractive in analysis with event shapes. We give the definition of angularity for DIS and factorize the cross-section by using soft-collinear effective theory. The factorization is valid in a wide range of $a$ below and above thrust region but invalid in broadening limit. It contains an angularity beam function, which is new result and we give the expression at $\mathcal{O}(\as)$. We also perform large log resummation of angularity and make predictions at various values of $a$ at next-to-next-to-leading log accuracy.