Accurate QCD predictions for new variables to study dilepton transverse momentum

TL;DR

This paper presents precise QCD predictions for the phi* variable in Drell-Yan processes, combining NNLL resummation with NLO calculations, and demonstrates good agreement with experimental data, improving understanding of low transverse momentum Z boson production.

Contribution

The study introduces a novel theoretical prediction for the phi* variable using combined NNLL resummation and NLO calculations, enhancing accuracy in low Q_T domain analysis.

Findings

Significant difference from fixed order calculations in the phi* distribution.

Resummation is essential for accurate predictions in the low Q_T region.

Good agreement with D0 experimental measurements.

Abstract

We report on the computation of the angle-between-leptons distribution in Drell-Yan processes. More precisely we study the recently introduced variable phi*, which provides us with a more accurate probe of the low Q_T domain of Z boson production at hadron colliders. Our theoretical prediction is obtained by matching a next-to-next-to leading logarithmic (NNLL) resummation to a fixed order calculation at next-to-leading order (NLO). We find that the result significantly differs from a pure fixed order calculation in a wide range of the observable we are interested in, clearly indicating the need for resummation. We also perform a first comparison to the measurement by the D0 collaboration, finding good agreement between theory and experiment.