Vector boson production in association with a jet at forward rapidities

Abstract

Final states with a vector boson and a hadronic jet allow one to infer the Born-level kinematics of the underlying hard scattering process, thereby probing the partonic structure of the colliding protons. At forward rapidities, the parton collisions are highly asymmetric and resolve the parton distributions at very large or very small momentum fractions, where they are less well constrained by other processes. Using theory predictions accurate to next-to-next-to-leading order (NNLO) in QCD for both and production in association with a jet at large rapidities at the LHC, we perform a detailed phenomenological analysis of recent LHC measurements. The increased theory precision allows us to clearly identify specific kinematical regions where the description of the data is insufficient. By constructing ratios and asymmetries of these cross sections, we aim to identify possible origins of the deviations, and highlight the potential impact of the data on improved determinations of parton distributions. Electronic supplementary material The online version of this article (10.1140/epjc/s10052-019-7010-2) contains supplementary material, which is available to authorized users.

NNLO QCD predictions for W+c-jet production at the LHC

“…refs. [7,24,60] and references therein). The scale uncertainty of fiducial cross sections and differential distributions is obtained by taking the envelope of the 7-point variations of the renormalization and factorization scale i.e.…”

“…While the (experimentally inaccessible) total inclusive cross section for bb and cc production can be inferred in NNLO QCD from existing tt calculations [1][2][3][4] no differential observable related to b or c production was known at NNLO in QCD until very recently. This situation can be contrasted with light-flavor production whose description in NNLO QCD has been established years ago by several groups in W+jet processes [5][6][7] and inclusive jet production [8][9][10][11][12], as well with top-quark production which has also been known in NNLO QCD [13][14][15][16][17][18][19][20][21][22][23] for some time.…”

Precision phenomenology with MCFM

“…Apart from FEWZ [13], no (public) code is known to the authors that computes PDF uncertainties automatically while taking into account correlations between PDF set members. Indeed, studies commonly avoid the expensive calculation of fixed order NNLO results convoluted with different PDF sets for central values and PDF uncertainties, for example [43,44]. Instead, relative PDF uncertainties or differences between sets are calculated using fixed order NLO matrix elements convoluted with NNLO PDFs.…”

Exploring the scattering of vector bosons at LHCb

“…Nonetheless, to obtain the subleading QCD contributions at order O α 4 α 2 s in the channels WZ and ZZ, the next-to-leading order (NLO) QCD corrections should be computed. For V+j, in a similar set-up, they have been found to be about +30% [12].…”