Bhabha scattering at NNLO with next-to-soft stabilisation

Banerjee, Pulak; Engel, Tim; Schalch, Nicolas; Signer, Adrian; Ulrich, Yannick

doi:10.1016/j.physletb.2021.136547

Bhabha scattering at NNLO with next-to-soft stabilisation

Banerjee, Pulak; Engel, Tim; Schalch, Nicolas; Signer, Adrian; Ulrich, Yannick

Authors

Pulak Banerjee

Tim Engel

Nicolas Schalch

Adrian Signer

Dr Yannick Ulrich yannick.ulrich@durham.ac.uk
Academic Visitor

Abstract

A critical subject in fully differential QED calculations originates from numerical instabilities due to small fermion masses that act as regulators of collinear singularities. At next-to-next-to-leading order (NNLO) a major challenge is therefore to find a stable implementation of numerically delicate real-virtual matrix elements. In the case of Bhabha scattering this has so far prevented the development of a fixed-order Monte Carlo at NNLO accuracy. In this paper we present a new method for stabilising the real-virtual matrix element. It is based on the expansion for soft photon energies including the non-universal subleading term calculated with the method of regions. We have applied this method to Bhabha scattering to obtain a stable and efficient implementation within the McMule framework. We therefore present for the first time fully differential results for the photonic NNLO corrections to Bhabha scattering.

Citation

Banerjee, P., Engel, T., Schalch, N., Signer, A., & Ulrich, Y. (2021). Bhabha scattering at NNLO with next-to-soft stabilisation. Physics Letters B, 820, https://doi.org/10.1016/j.physletb.2021.136547

Journal Article Type	Article
Acceptance Date	Jul 21, 2021
Online Publication Date	Jul 24, 2021
Publication Date	2021
Deposit Date	Nov 15, 2021
Publicly Available Date	Nov 15, 2021
Journal	Physics Letters B
Print ISSN	0370-2693
Publisher	Elsevier
Peer Reviewed	Peer Reviewed
Volume	820
DOI	https://doi.org/10.1016/j.physletb.2021.136547