- The paper demonstrates that including NLL soft gluon resummation significantly improves theoretical predictions for squark–antisquark and gluino-pair production at the LHC.
- It employs a one-loop soft anomalous dimension matrix to capture wide-angle soft gluon emissions and reduce scale uncertainties.
- Results show NLL corrections can enhance gluino-pair production cross sections by up to 16% for heavy gluino masses, impacting experimental discovery strategies.
Threshold Resummation for Squark-Antisquark and Gluino-Pair Production at the LHC
This paper presents a detailed analysis of threshold resummation effects in the production of squark-antisquark pairs and gluino-gluino pairs in the context of the Large Hadron Collider (LHC) at 14 TeV. The work is conducted within the framework of the Minimal Supersymmetric Standard Model (MSSM) and focuses on the next-to-leading logarithmic (NLL) accuracy. The primary objective is to enhance the theoretical predictions for the associated cross sections by systematically incorporating the contributions from soft gluon emissions.
Summary of Key Findings
The authors emphasize the importance of soft gluon emissions, which are particularly significant in the proximity of the partonic production threshold—where the center-of-mass energy nearly equals twice the mass of the produced heavy particles. Such conditions amplify the effects of soft gluon emission and necessitate resummation to all orders in perturbation theory for accurate predictions. This resummation is critical because it reduces the renormalization and factorization scale dependence of the theoretical predictions, thereby offering reduced theoretical uncertainties.
The paper presents the calculation of the one-loop soft anomalous dimension matrices which are integral to understanding the color evolution in these scattering processes. This calculation allows for the consideration of non-collinear soft gluon emissions at wide angles and the application of NLL resummation techniques. Furthermore, the paper provides the resummed total cross sections for both gluino-pair and squark-antisquark production channels.
The resummed predictions revealed that the NLL contributions to the cross section for gluino-gluino production are more substantial when compared to squark-antisquark production. For instance, the relative NLL correction, KNLL−1, for gluino-pair production reached up to 16% for gluino masses around 2 TeV, underscoring the importance of including these higher-order effects in accurate modeling. Additionally, the inclusion of soft gluon effects notably reduces the sensitivity of cross section predictions to variations in renormalization and factorization scales.
Implications and Future Directions
The findings have implications for the theoretical studies and experimental strategies at the LHC. Accurate cross section predictions are crucial for the discovery potential of supersymmetric particles like squarks and gluinos. The improved theoretical accuracy in calculating cross sections can either facilitate the mass determination of these particles upon discovery or provide more stringent exclusion limits on their mass parameters if they are not observed.
Future directions indicated by this paper might include extending this framework to incorporate next-to-next-to-leading logarithmic (NNLL) effects or combining soft gluon and Coulomb resummation, which would provide even more precision. Additionally, the methods and results obtained can be leveraged for other heavy particle production processes in supersymmetric models, expanding the applicability of this paper within the broader field of particle physics.
In conclusion, the paper successfully demonstrates the importance and impact of resumming threshold logarithms for the production of supersymmetric particles at the LHC, providing a robust theoretical foundation for future experimental analyses.
