The NNLO QCD corrections to Z boson production at large transverse momentum

Abstract

Abstract:The transverse momentum distribution of massive neutral vector bosons can be measured to high accuracy at hadron colliders. The transverse momentum is caused by a partonic recoil, and is determined by QCD dynamics. We compute the single and double-differential transverse momentum distributions for fully inclusive Z/γ * production including leptonic decay to next-to-next-to-leading order (NNLO) in perturbative QCD. We also compute the same distributions normalised to the cross sections for inclusive Z/γ * production, i.e. integrated over the transverse momentum of the lepton pair. We compare our predictions for the fiducial cross sections to the 8 TeV data set from the ATLAS and CMS collaborations, which both observed a tension between data and NLO theory predictions, using the experimental cuts and binning. We find that the inclusion of the NNLO QCD effects does not fully resolve the tension with the data for the unnormalised p Z T distribution. However, we observe that normalising the NNLO Z-boson transverse momentum distribution by the NNLO Drell-Yan cross section substantially improves the agreement between experimental data and theory, and opens the way for precision QCD studies of this observable.

NNLO QCD corrections to Higgs boson production at large transverse momentum

“…This program provides the necessary infrastructure for the antenna subtraction of hadron collider processes at NNLO and performs the integration of all contributing subprocesses at this order. Components of it have also been used in other NNLO QCD calculations [48][49][50][51][52][53][54][55] using the antenna subtraction method. Other processes can be added to NNLOJET provided the matrix elements are available.…”

NNLO QCD corrections to jet production in deep inelastic scattering

“…Following earlier results on the Drell-Yan process [43,44], on Higgs production [45,46] and on e + e − → 3j [47][48][49], NNLO results have been obtained in recent years for pp → γγ [50,51], pp → V H [52], pp → V γ [53], pp → tt [54,55], pp → H +j [56][57][58], pp → W +j [59], pp → Z +j [60][61][62][63], pp → γ+X [64], pp → ZZ [65,66], pp → W W [67,68], pp → ZW [69], ep → 1j [70] and pp → 2j [71,72]. All these calculations were implemented in the form of parton-level event generators (some of the lowermultiplicity processes have also become part of the latest version of the MCFM code [73]), which provide full kinematical information on all final state particles, and consequently allow to account for the precise definition (jet algorithm, kinematical acceptance cuts) of observables used in the experimental analyses.…”

“…Our NNLOjet implementation [74] of jet production in DIS uses the same matrix elements [75][76][77][78][79][80][81][82][83][84] as were used in Z + j production [60][61][62], however in different kinematical crossings. While the phase space for Z +j production corresponds to a single crossing region of the matrix elements, three different crossing regions are required [20,21,101,102] to describe each DIS process, depending on the relative size of Q 2 compared to the partonparton invariants.…”

“…[99,100]. Processes included in NNLOjet up to now are Z and Z + j production [60][61][62], H and H + j production [58] as well as di-jet production in hadron-hadron collisions [71,72].…”

“…This method forms the basis of the NNLOjet code, which provides the necessary infrastructure and building blocks to implement NNLO corrections to different collider processes. Up to now, pp → Z + j [60][61][62], pp → H + j [58] and pp → 2j [71,72] have been implemented in NNLOjet.…”