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

Ankita Budhraja, Ambar Jain, Massimiliano Procura
2019 Journal of High Energy Physics  
Angularities are event shapes whose sensitivity to the splitting angle of a collinear emission is controlled by a continuous parameter b, with −1 < b < ∞. 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 = 0 can be
more » ... with b = 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 oneloop order in α 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 0.5. Our calculations are checked against various limits known in the literature and agree with the numerical output of the Event2 generator.
doi:10.1007/jhep08(2019)144 fatcat:oggugz5b2rfkdlwt5eprygvqb4