Infrared sensitivity of single jet inclusive production at hadron colliders

TL;DR

The paper investigates infrared sensitivity in the single jet inclusive cross section at hadron colliders using NNLO QCD, focusing on how renormalization and factorization scale choices and jet kinematics influence higher-order cancellations. It analyzes the decomposition into leading and subleading jet contributions, identifying the second-jet distribution as a key source of instability and showing how scale choices affect IR cancellations. Through a set of convergence criteria, it evaluates a broad class of scales and recommends two robust options: a jet-based 2$p_T$ and an event-based $\hat{H}_T$, which improve perturbative convergence and reduce scale uncertainties. The authors validate these scales by comparing with CMS 13 TeV data, finding improved agreement and reliable uncertainty estimates, thereby supporting more precise QCD studies and PDF/α_s extractions from jet observables.

Abstract

Jet production at hadron colliders is a benchmark process to probe the dynamics of the strong interaction and the structure of the colliding hadrons. One of the most basic jet production observables is the single jet inclusive cross section, which is obtained by summing all jets that are observed in an event. Our recent computation of next-to-next-to-leading order (NNLO) QCD contributions to single jet inclusive observables uncovered large corrections in certain kinematical regions, which also resulted in a sizeable ambiguity on the appropriate choice of renormalization and factorization scales. We now perform a detailed investigation of the infrared sensitivity of the different ingredients to the single jet inclusive cross section. We show that the contribution from the second jet, ordered in transverse momentum $p_{T}$, in the event is particularly sensitive to higher order effects due to implicit restrictions on its kinematics. By investigating the second-jet transverse momentum distribution, we identify large-scale cancellations between different kinematical event configurations, which are aggravated by certain types of scale choice. Taking perturbative convergence and stability as selection criteria enables us to single out the total partonic transverse energy $\hat{H}_{T}$ and twice the individual jet transverse momentum $2\,p_{T}$ (with which $\hat{H}_{T}$ coincides in Born kinematics) as the most appropriate scales in the perturbative description of single jet inclusive production.

Figures (21)

• Figure 1: Illustrations of jet events at LO and NLO with arrows representing partons and cones representing jets.
• Figure 2: An illustration of 2-jet NNLO configurations that contribute to the $p_\mathrm{T}\xspace\xspace$ imbalance between the leading and subleading jet with arrows representing partons and cones representing jets.
• Figure 4: Perturbative corrections to the single jet inclusive distribution at 13 TeV (CMS cuts, $|y| < 4.7$, $R=0.7$), integrated over rapidity and normalised to lower order predictions. Central scale choice: (a) $\mu=p_{\mathrm{T}\xspace,1}\xspace$, (b) $\mu=p_\mathrm{T}\xspace\xspace$.
• Figure 5: Perturbative corrections to the single jet inclusive distribution at 13 TeV (CMS cuts, $|y| < 4.7$, $R=0.4$), integrated over rapidity and normalised to lower order predictions. Central scale choice: (a) $\mu=p_{\mathrm{T}\xspace,1}\xspace$ and (b) $\mu=p_\mathrm{T}\xspace\xspace$.
• Figure 6: Ratio between predictions for the single jet inclusive distribution integrated over rapidity obtained with $\mu=p_{\mathrm{T}\xspace,1}\xspace$ and $\mu=p_\mathrm{T}\xspace\xspace$ at NLO (blue) and NNLO (red) for different jet resolution: (a) $R=0.7$; (b) $R=0.4$.