# Higher order corrections to spin correlations in top quark pair production at the LHC

## TL;DR

This paper presents the first calculation of NNLO QCD corrections to spin correlations in top quark pair production at the LHC, improving theoretical predictions for differential distributions.

## Contribution

It introduces the first NNLO QCD corrections to top quark spin correlations, enhancing the accuracy of theoretical models compared to previous NLO calculations.

## Key findings

- NNLO corrections significantly affect differential distributions.
- Standard Model matches fiducial data but not full phase space measurements.
- Discrepancies likely due to differences in precision between event generators and NNLO calculations.

## Abstract

We calculate, for the first time, the next-to-next-to leading order (NNLO) QCD corrections to spin correlations in top quark pair production at the LHC. The NNLO corrections play an important role in the description of the corresponding differential distributions. We observe that the Standard Model calculation describes the available delta-phi data in the fiducial region but does not agree with the delta-phi measurement extrapolated to full phase space. Most likely this discrepancy is due to the difference in precision between existing event generators and NNLO calculations for dilepton top-pair final states.