QED radiative corrections toZboson production and the forward-backward asymmetry at hadron colliders

Abstract

The O(α) radiative corrections to the process p p (−) → γ * , Z → ℓ + ℓ − (ℓ = e, µ) are calculated. Factorizing the collinear singularity associated with initial state photon bremsstrahlung into the parton distribution functions, we find that initial state corrections have a much smaller effect than final state radiative corrections. Due to mass singular logarithmic terms associated with photons emitted collinear with one of the final state leptons, QED radiative corrections strongly affect the shape of the di-lepton invariant mass distribution, the lepton transverse momentum spectrum, and the forward backward asymmetry, A F B . They lead to a sizeable shift in the Z boson mass extracted from data, decrease the di-lepton cross section by up to 10%, and increase the integrated forward backward asymmetry in the Z peak region by about 7% at the Tevatron. We also investigate how experimental lepton identification requirements modify the effect of the QED corrections, and study the prospects for a high precision measurement of sin 2 θ lept ef f using the forward backward asymmetry at the Large Hadron Collider (LHC).

Two-loop master integrals for the mixed EW-QCD virtual corrections to Drell-Yan scattering

“…JHEP09(2016)091 21) JHEP09(2016)091 23) JHEP09(2016)091 24) and (M 12 ) 32,32 = −1 is the only non vanishing entry in M 12 .…”

“…Therefore, already at the NLO, massive four-point functions have to be evaluated. Since the bulk of the corrections for inclusive observables comes from the resonant region, in which the exchanged vector boson is nearly on-shell, electroweak NLO corrections to the total cross section were calculated for the W [20] and Z [21] in narrow-width approximation.…”

NNLOPS accurate Drell-Yan production

“…Although we have also explored the effect of using the alternative prescription first introduced in section 4 of ref. [41] to compute the scale used by the parton shower to veto hard emissions (which is also available as an option in the Pythia8 driver), 6 the plots shown throughout the paper have been obtained keeping the veto scale equal to the default POWHEG prescription, both for Pythia6 and Pythia8.…”

“…Two public codes exist (DYNNLO [4] and FEWZ [5]) that implement QCD NNLO corrections to the hadronic W and Z production. Furthermore electroweak corrections have been the subject of intensive studies [6][7][8][9][10][11]. Electroweak Sudakov effects become more important at large invariant mass [9,[12][13][14], a region that was already interesting at run I and which will be explored even more during the next LHC run.…”

Electroweak radiative corrections to weak boson production at hadron colliders

“…[ 8,9] and [ 10,11,12,13], concentrating on photon radiation effects and the impact of non-resonant weak corrections on the W width measurement.…”