One-loop electroweak Sudakov logarithms: a revisitation and automation

Journal of High Energy Physics

Davide Pagani¹  Marco Zaro² 

[1] INFN, Sezione di Bologna, Via Irnerio 46, 40126, Bologna, Italy;Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany;TIFLab, Università degli Studi di Milano & INFN, Sezione di Milano, Via Celoria 16, 20133, Milano, Italy;

关键词: NLO Computations;   

DOI  :  10.1007/JHEP02(2022)161

来源: Springer

【 摘 要 】

In this work we revisit the algorithm of Denner and Pozzorini for the calculation of one-loop electroweak Sudakov logarithms and we automate it in the MadGraph5_aMC-@NLO framework. We adapt the formulas for modern calculations, keeping light-quarks and photons strictly massless and dealing with infrared divergences via dimensional regularisation. We improve the approximation by taking into account additional logarithms that are angular dependent. We prove that an imaginary term has been previously omitted and we show that it cannot be in general neglected for 2 → n processes with n > 2. We extend the algorithm to NLO EW corrections to squared matrix-elements that involve also QCD corrections on top of subleading LO terms. Furthermore, we discuss the usage of this algorithm for approximating physical observables and cross sections. We propose a new approach in which the QED component is consistently removed and we show how it can be superior to the commonly used approaches. The relevance of all the novelties introduced in this work is corroborated by numerical results obtained for several processes in a completely automated way. We thoroughly compare exact NLO EW corrections and their Sudakov approximations both at the amplitude level and for physical observables in high-energy hadronic collisions.

【 授权许可】

CC BY