- The paper comprehensively analyzes squark and gluino pair production at hadron colliders (Tevatron, LHC) using NLO and NLL supersymmetric QCD corrections.
- Implementing NLO QCD calculations refined by NLL threshold resummation significantly reduces scale dependence and enhances cross-section predictions by up to 20%.
- These precise theoretical predictions are crucial for setting accurate exclusion limits on SUSY models and interpreting results from ongoing and future collider experiments.
Overview of Squark and Gluino Hadroproduction
The paper authored by Wim Beenakker et al. provides a comprehensive review and numerical analysis of squark and gluino pair production at hadron colliders, specifically focusing on the Tevatron and the Large Hadron Collider (LHC). The research addresses the theoretical framework of these processes within the context of the minimal supersymmetric extension of the Standard Model (MSSM), which predicts the existence of squarks and gluinos as color-charged supersymmetric particles. This paper is essential to interpret the results of ongoing and future supersymmetry (SUSY) searches at hadron colliders.
Theoretical Context
The production of squarks and gluinos in hadronic collisions is a critical testing ground for SUSY theories, providing sensitivity to weak-scale supersymmetry. The paper targets the hadroproduction of these sparticles, taking into account the effects of next-to-leading order (NLO) supersymmetric QCD corrections and the resummation of soft-gluon emissions at next-to-leading-logarithmic (NLL) accuracy. Such corrections are fundamental to improving the accuracy and reliability of theoretical cross-section predictions, which are pivotal for both setting exclusion limits on SUSY models and measuring SUSY particle properties upon potential discovery.
Methodological Approach
The authors employ NLO QCD calculations refined by NLL threshold resummation to account for large logarithmic corrections near production thresholds. The resummation is crucial in reducing scale dependence, which enhances the precision of the cross-section calculations. The analysis encompasses a wide range of final states: squark-squark, squark-antisquark, squark-gluino, gluino-gluino, and top squark (stop) pair production. The predictions specifically include higher-order QCD corrections, which impact the cross-section size and reduce theoretical uncertainties, providing a significant refinement over leading-order (LO) results.
Numerical Predictions and Results
The results highlight that higher-order corrections lead to a substantial decrease in scale dependence, offering a more stabilized cross-section prediction across the energy spectrum. For instance, at the LHC with a center-of-mass energy of 7 TeV, the researchers find that NLL resummation enhances the cross-section predictions by up to 20% for gluino-pair and squark-gluino production for sparticle masses around 1 TeV. The paper also discusses the dependence of these corrections on the ratios of squark to gluino mass, underscoring a substantial sensitivity to SUSY mass hierarchy models.
Implications and Future Directions
The research underscores the importance of incorporating SUSY-QCD corrections in the analysis of squark and gluino production processes. Such corrections not only provide a more precise exclusion limit for SUSY mass parameters but also pave the way for a more accurate determination of these parameters if empirical evidence of SUSY is encountered. The results carry profound implications for experimental strategies at the LHC and future colliders, facilitating more informed experimental searches and efficient data analysis approaches.
Looking forward, the techniques and findings discussed in this paper could be extrapolated to explore other potential SUSY signals or be adapted to new collider experiments that aim to investigate beyond-the-Standard-Model physics. The framework and methodologies established for threshold resummation and cross-section computation are versatile tools, potentially extendable to other particle sectors as experimental capabilities advance. Additionally, developments in parton distribution functions and QCD methodology could further refine these studies, providing even more precise theoretical predictions.
Conclusion
This paper by Beenakker et al. presents a pivotal exploration of squark and gluino hadroproduction, utilizing advanced theoretical techniques to enhance the understanding and predictive power of SUSY searches at modern particle colliders. The integration of NLO and NLL corrections offers a robust platform for probing the SUSY landscape with unprecedented precision, contributing significantly to the particle physics community's broader effort to unravel the compositional complexities of the universe.