Precision studies for Drell-Yan processes at NNLO

We present a detailed comparison of the fixed-order predictions computed by four publicly available computer codes for Drell-Yan processes at the LHC and Tevatron colliders. We point out that while there is agreement among the predictions at the next-to-leading order accuracy, the predictions at the next-to-next-to-leading order (NNLO) differ, whose extent depends on the observable. The sizes of the differences in general are at least similar, sometimes larger than the sizes of the NNLO corrections themselves. We demonstrate that the neglected power corrections by the codes that use global slicing methods for the regularization of double real emissions can be the source of the differences. Depending on the fiducial cuts, those power corrections become linear, hence enhanced as compared to quadratic ones that are considered standard.

Automated summary

A detailed comparison was made for four publicly available computer codes computing fixed-order predictions for Drell-Yan processes at the LHC and Tevatron colliders. It was found that while there is agreement among the predictions at NLO accuracy, differences arise at NNLO, potentially due to neglected power corrections in the codes using global slicing methods for double real emissions regularization.