- The paper demonstrates that soft gluon resummation at NLL accuracy significantly stabilizes cross section predictions for gluino-gluino and squark-antisquark production.
- The paper employs Mellin transform techniques and one-loop soft anomalous dimension matrices to accurately capture logarithmic contributions in the threshold region.
- The paper shows that including soft gluon and Coulombic corrections reduces scale dependence and sharpens theoretical predictions for supersymmetric particle searches.
Overview of Soft Gluon Resummation for Gluino-Gluino and Squark-Antisquark Production at the LHC
This paper investigates the detailed effects of soft gluon emission on the production of pairs of gluinos and squarks at the Large Hadron Collider (LHC) within the framework of the Minimal Supersymmetric Standard Model (MSSM). Specifically, the study presents a comprehensive analysis of resummed cross sections with next-to-leading logarithmic (NLL) accuracy, spotlighting the crucial role of soft gluon corrections in the threshold region of these processes, which are inherently colored due to the presence of squarks and gluinos.
Theoretical Context
In the MSSM, the production of squarks and gluinos, which are the supersymmetric partners of quarks and gluons respectively, forms a key research interest given their potential to hint at physics beyond the Standard Model (SM). Within the LHC's high-energy environment, these processes are particularly relevant, as they predominantly occur with high cross sections when colored particles are in the final state. The paper discusses that the hadroproduction cross sections are significantly affected by next-to-leading order (NLO) QCD corrections, with gluino-gluino (gg) processes receiving corrections of nearly 100% under certain parameter conditions. This highlights the essential need for precise theoretical predictions.
Methodology
The paper utilizes the technique of soft gluon resummation to compute higher-order QCD corrections, emphasizing the importance of capturing logarithmic contributions from soft gluon emissions. The resummation is performed at NLL accuracy using Mellin transform techniques, which aid in handling the threshold logarithms that could potentially compromise fixed-order perturbative predictions. The one-loop soft anomalous dimension matrices governing the evolution of color flow in these processes are derived and analyzed. This requires sophisticated calculation of eikonal diagrams to understand the interplay between soft gluons and the color states of the interacting particles.
Numerical Analysis and Results
The analysis presented extends to the exploration of numerical results for proton-proton collisions at the LHC. Highlighted within the paper is a thorough examination of the resummed cross sections, showcasing their dependence on the masses of squarks and gluinos as well as the mass scale ratios. Importantly, the study quantifies the reduction in scale dependence afforded by NLL resummation, showing that incorporating these corrections significantly stabilizes the theoretical predictions even at scale variations, which previously were a source of substantial uncertainty.
In particular, the paper identifies that the soft gluon effects are considerably pronounced in channels involving gluons due to the heavier color charge. Additionally, it introduces a critical component by accounting for leading Coulombic corrections beyond NLO, which prove to be significant in massive colored sparticle production processes.
Implications and Future Directions
The implications of this research are profound for both theoretical and experimental physics at hadron colliders. Theoretical accuracy improvements could better inform the parameter spaces for sparticle discovery at the LHC, guide experimental searches, and refine exclusion limits. The method is not confined to this specific context but may also be applicable to other processes involving massive colored particles, extending the utility of the findings.
Future developments may involve higher resummation accuracy, such as next-to-next-to-leading logarithm (NNLL) resummation, or adapting the method for more complex new physics scenarios, potentially relating to other Beyond Standard Model (BSM) phenomena. The stability and precision of such predictions will be instrumental as the LHC and future colliders probe deeper into the high-energy frontier.
In conclusion, this research provides a robust framework for understanding and predicting the hadroproduction of supersymmetric particles in a collider environment, emphasizing both theoretical precision and practical applicability in the search for new physics.