2020/09/04 by Stefan Dittmaier, Timo Schmidt, Jan Schwarz
Computer Science · Physics and Astronomy · #Boson #Computational Physics and Python Applications #Electroweak interaction #Fermion #Large Hadron Collider #Monte Carlo method #Observable #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #Radiative transfer #Renormalization #Standard Model (mathematical formulation) #hep-ph
paper · pdf · doi:10.1007/jhep12(2020)201
38 pages, latex, 8 figures, 3 ancillary files
arxiv created 2020/09/04 · openalex created_date 2020/09/11 · openalex publication_date 2020/12/30 · arxiv updated 2021/02/03 · openalex updated_date 2026/08/05
A bstract First results on the radiative corrections of order O <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> </mml:math> ( N f α s α ) are presented for the off-shell production of W or Z bosons at the LHC, where N f is the number of fermion flavours. These corrections comprise all diagrams at O <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> </mml:math> ( α s α ) with closed fermion loops, form a gauge-invariant part of the next-to-next-to-leading-order corrections of mixed QCD×electroweak type, and are the ones that concern the issue of mass renormalization of the W and Z resonances. The occurring irreducible two-loop diagrams, which involve only self-energy insertions, are calculated with current standard techniques, and explicit analytical results on the electroweak gauge-boson self-energies at O <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> </mml:math> ( α s α ) are given. Moreover, the generalization of the complex-mass scheme for a gauge-invariant treatment of the W/Z resonances is described for the order O <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>O</mml:mi> </mml:math> ( α s α ). While the corrections, which are implemented in the Monte Carlo program R ady , are negligible for observables that are dominated by resonant W/Z bosons, they affect invariant-mass distributions at the level of up to 2% for invariant masses of ≳ 500 GeV and are, thus, phenomenologically relevant. The impact on transverse-momentum distributions is similar, taking into account that leading-order predictions to those distributions underestimate the spectrum.