- The paper demonstrates that NNLO QCD corrections increase the inclusive W+W- cross-section by 9% at 7 TeV and 12% at 14 TeV.
- It introduces a novel framework to mitigate top-quark contamination using distinct definitions in the 4FNS and 5FNS.
- Residual perturbative uncertainties are constrained to about 3%, providing more robust theoretical predictions for collider experiments.
Overview of W+W− Production at Hadron Colliders in NNLO QCD
This paper presents significant advancements in the theoretical predictions of W+W− production at hadron colliders, utilizing next-to-next-to-leading order (NNLO) Quantum Chromodynamics (QCD) calculations. The precise treatment of W+W− cross-section is critical for exploring the fundamental electroweak interactions and serves as an important background for Higgs boson measurements and searches for new physics.
The authors develop a comprehensive NNLO QCD framework to enhance previous next-to-leading order (NLO) predictions. With this advanced theory, they analyze perturbative uncertainties and propose methods to accurately separate W+W− production from significant top-quark contamination. Key results from this paper include a demonstrated enhancement of the inclusive W+W− cross-section at both 7 TeV and 14 TeV energies, and the authors report a remaining perturbative uncertainty constrained to approximately 3%.
Key Numerical Results
The paper provides a detailed breakdown of the inclusive W+W− cross-sections:
- At 7 TeV, NNLO QCD corrections enhance the cross-section by 9%, with a similar trend observed at 12% for 14 TeV collisions.
- These NNLO corrections reduce the residual scale dependence effectively presenting a more robust estimation of theoretical uncertainties.
These numerical outcomes offer a critical benchmark and demonstrate improved alignment with empirical data measured at the Large Hadron Collider (LHC) compared to earlier results. Importantly, the NNLO calculations reveal that previously observed discrepancies with the data can be substantially mitigated, diminishing the possibility of assumed new physics contributions.
Addressing Top-Quark Contamination
The analysis addresses the contamination from top-quark resonances by providing a methodology for distinguishing top-quark contributions without compromising theoretical precision. This is achieved by adopting distinct theoretical definitions of “top-free” W+W− production within both the four-flavour number scheme (4FNS) and five-flavour number scheme (5FNS). By employing a top-quark subtraction protocol in the 5FNS, the authors manage to produce consistent predictions that align with those from the 4FNS, hence reinforcing the credibility of their approach.
Implications and Future Directions
The advancements in NNLO QCD calculations for W+W− production hold substantial implications for both practical applications and theoretical explorations. Practically, these results significantly enhance our understanding of background processes in Higgs boson studies and improve the accuracy of simulations at colliders. Theoretically, the method set forth provides a pathway to explore precision measurement questions related to the electroweak sector further.
Future research may extend these computations to even more exclusive observables, including differential cross-sections and W+W− spin correlations, which could provide deeper insights into weak gauge boson interactions and potential beyond the Standard Model phenomena.
This paper serves as an essential contribution to advancing collider physics predictions, reinforcing the theoretical foundation necessary for ongoing and future experiments at high-energy physics facilities.