Towards NNLO corrections in B --> D pi

TL;DR

This paper discusses the progress in calculating NNLO QCD corrections for the B to D pi decay, focusing on the color-singlet hard-scattering kernel using advanced multi-loop techniques.

Contribution

It provides the first NNLO calculation of the color-singlet hard-scattering kernel for B to D pi decay using multi-loop methods.

Findings

Calculation of the color-singlet hard-scattering kernel completed.

Application of Laporta's reduction, Mellin-Barnes, and differential equations techniques.

Advances towards precise theoretical predictions for B decay processes.

Abstract

We describe the status of the calculation of the branching ratio for the decay \bar B^0 --> D^+ pi^- to NNLO in QCD factorization. Here, we present the result for the colour-singlet hard-scattering kernel. The calculation has been performed using multi-loop techniques like Laporta's reduction to master integrals, and Mellin-Barnes representations and differential equations for evaluating the latter.