Triple Differential Dijet Cross Section at the LHC

TL;DR

It is computed for the first time the second-order perturbative QCD corrections to this triple-differential dijet cross section, at leading color in all partonic channels, thereby enabling precision studies with LHC dijet data.

Abstract

The measurement of the triple-differential dijet production cross section as a function of the average transverse momentum $p_{T,\textrm{avg}}$, half the rapidity separation $y^{*}$, and the boost $y_{b}$ of the two leading jets in the event enables a kinematical scan of the underlying parton momentum distributions. We compute for the first time the second-order perturbative QCD corrections to this triple-differential dijet cross section, at leading color in all partonic channels, thereby enabling precision studies with LHC dijet data. A detailed comparison with experimental CMS 8 TeV data is performed, demonstrating how the shape of this differential cross section probes the parton densities in different kinematical ranges.

Figures (4)

• Figure 1: Allowed kinematical regions at LO in the triple differential dijet inclusive cross section (in pb) at $\sqrt{s}=8$ TeV in the partonic fraction $x_{1},x_{2}$ plane for the jet $p_{T}$ cuts of the CMS measurement.
• Figure 2: The triple differential dijet cross section as a function of $p_{T,\textrm{avg}}$ for the six bins of $y^{*}, y_{b}$ at NNLO with central scale choice $\mu=m_{jj}$, compared to CMS 8 TeV 19.7 fb$^{-1}$ data.
• Figure 3: NLO/LO (blue) and NNLO/NLO (red) $K$ factors triple differential in $p_{T,\textrm{avg}}$, $y^{*}$ and $y_{b}$. Bands represent the scale variation of the numerator. NNLO PDFs are used for all predictions.
• Figure 4: The NLO (blue) and NNLO (green) theory predictions and CMS data normalized to the NLO central value. Parton-level predictions corrected for nonperturbative (NP) effects and combined NP and Electroweak effects (EWK), implemented as a multiplicative factor to the NNLO result, are shown shown in pink and red. The shaded bands shown for the NLO and the NNLO$\otimes$NP$\otimes$EWK predictions represent the variation of the theoretical scales in the numerator by factors of 0.5 and 2. The uncertainty in the data is the total experimental uncertainty, including systematic and statistical uncertainties added in quadrature.