Massive event-shape distributions at N²LL

Author(s)

Alejandro Bris, Vicent Mateu, Moritz Preisser

Abstract

In a recent paper we have shown how to optimally compute the differential and cumulative cross sections for massive event-shapes at O(ffs) in full QCD. In the present article we complete our study by obtaining resummed expressions for non-recoil-sensitive observables to N2LL + O(ffs) precision. Our results can be used for thrust, heavy jet mass and C-parameter distributions in any massive scheme, and are easily generalized to angularities and other event shapes. We show that the so-called E- and P-schemes coincide in the collinear limit, and compute the missing pieces to achieve this level of accuracy: the P-scheme massive jet function in Soft-Collinear Effective Theory (SCET) and boosted Heavy Quark Effective Theory (bHQET). The resummed expression is subsequently matched into fixed-order QCD to extend its validity towards the tail and fartail of the distribution. The computation of the jet function cannot be cast as the discontinuity of a forward-scattering matrix element, and involves phase space integrals in d = 4 2" dimensions. We show how to analytically solve the renormalization group equation for the P-scheme SCET jet function, which is significantly more complicated than its 2-jettiness counterpart, and derive rapidly-convergent expansions in various kinematic regimes. Finally, we perform a numerical study to pin down when mass effects become more relevant.

Organisation(s)

Particle Physics

External organisation(s)

Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca

Journal

Journal of High Energy Physics

No. of pages

58

ISSN

1029-8479

DOI

https://doi.org/10.1007/JHEP09(2020)132

Publication date

09-2020

Peer reviewed

Yes

Austrian Fields of Science 2012

103012 High energy physics

Keywords

Portal url

https://ucris.univie.ac.at/portal/en/publications/massive-eventshape-distributions-at-n2ll(0f69ac65-dcfd-4000-baf2-7b66705a2b31).html