One-loop angularity distributions with recoil using Soft-Collinear Effective Theory

Author(s): Ankita Budhraja, Ambar Jain, Massimiliano Procura
Abstract: Angularities are event shapes whose sensitivity to the splitting angle of a collinear emission is controlled by a continuous parameter b, with -1 <b <infinity. When measured with respect to the thrust axis, this class of QCD observables includes thrust (b = 1) and jet broadening (b = 0), the former being insensitive to the recoil of soft against collinear radiation, while the latter being maximally sensitive to it. Presently available analytic results for angularity distributions with b not equal 0 can be applied only close to the thrust limit since recoil effects have so far been neglected. As a first step to establish a comprehensive theoretical framework based on Soft-Collinear Effective Theory valid for all recoil-sensitive angularities, we compute for the first time angularity distributions at one-loop order in alpha(s) for all values of b taking into account recoil effects. In the differential cross section, these amount to novel sub-leading singular contributions and/or power corrections, where the former are characterized by fractional powers of the angularity and contribute appreciably close to the peak region, also for b greater than or similar to 0.5. Our calculations are checked against various limits known in the literature and agree with the numerical output of the Event2 generator.
Organisation(s): Particle Physics
External organisation(s): Indian Institute of Science, European Organization for Nuclear Research (CERN)
Journal: Journal of High Energy Physics
No. of pages: 46
ISSN: 1029-8479
DOI: https://doi.org/10.1007/JHEP08(2019)144
Publication date: 08-2019
Peer reviewed: Yes
Austrian Fields of Science 2012: 103012 High energy physics
Keywords
Portal url: https://ucris.univie.ac.at/portal/en/publications/oneloop-angularity-distributions-with-recoil-using-softcollinear-effective-theory(b4767a52-9281-40b7-9b1d-548477c0fd18).html