The total top quark pair production cross-section at hadron colliders through O(alpha_S^4)

Abstract: We compute the next-to-next-to-leading order (NNLO) QCD correction to the total cross-section for the reaction gg \to t\bar t + X. Together with the partonic channels we computed previously, the result derived in this letter completes the set of NNLO QCD corrections to the total top pair production cross-section at hadron colliders. Supplementing the fixed order results with soft-gluon resummation with next-to-next-to-leading logarithmic accuracy we estimate that the theoretical uncertainty of this observable due to unknown higher order corrections is about 3% at the LHC and 2.2% at the Tevatron. We observe a good agreement between the Standard Model predictions and the available experimental measurements. The very high theoretical precision of this observable allows a new level of scrutiny in parton distribution functions and new physics searches.

• The paper finalizes NNLO QCD corrections by computing the gg → t̄t + X channel with soft gluon resummation at NNLL accuracy.
• It reduces theoretical uncertainty to about 3% for LHC and 2.2% for Tevatron, enhancing the precision of collider predictions.
• The numerical results validate against experimental data and inform improvements in parton distribution functions and new physics searches.

Overview of "The Total Top Quark Pair Production Cross-Section at Hadron Colliders through $\mathcal{O}(\alpha_S^4)$"

The paper addresses the next-to-next-to-leading order (NNLO) quantum chromodynamics (QCD) corrections to the top quark pair production cross-section at hadron colliders, focusing specifically on the $gg \rightarrow t\bar{t} + X$ process. This contribution completes the full set of NNLO corrections to top quark pair production, providing a foundation for improved precision in theoretical predictions, crucial for analyses at the Large Hadron Collider (LHC) and the Tevatron.

Main Contributions

1. Computation of NNLO Corrections: The paper finalizes the calculation of NNLO QCD corrections to the total top quark pair production cross-section by deriving the corrections for the partonic channel $gg \rightarrow t\bar{t} + X$. The NNLO contributions were explicitly computed, including novel enhancements with soft gluon resummation at next-to-next-to-leading logarithmic (NNLL) accuracy.
2. Reduction in Uncertainty: Combining fixed-order NNLO predictions with soft-gluon resummation, the paper estimates a theoretical uncertainty on the order of 3% for LHC scenarios and 2.2% for the Tevatron, attributed to unknown higher-order corrections. This is a significant advancement in the precision available for QCD predictions relevant to collider experiments.
3. Numerical Results and Validations: The paper provides explicit numerical results for the NNLO corrections, significantly impacting the integrated cross-section, particularly noting the large contributions from power corrections. The resummed NNLO results were cross-validated against existing experimental data, demonstrating good agreement.
4. Implications for PDFs and New Physics: With such high theoretical precision, the computed cross-sections have direct implications for refining parton distribution functions (PDFs) and searching for new physics, given their sensitivity to fundamental quantities.

Implications and Future Work

The completion of NNLO QCD predictions for top quark pair production marks a significant stride in the precision achievable for hadron collider processes. The successful agreement between theoretical predictions and experimental results reinforces confidence in the Standard Model while setting the stage for exploring deviations that might signal new physics. Future developments in this domain may include extending these precise calculations to processes of even greater complexity, leveraging the methods and insights gained from this work. Furthermore, the incorporation of electroweak corrections and potential further refinements in resummation techniques could offer additional avenues to push the boundaries of precision in particle physics.