The width difference in the $B_s$-$\bar B_s$ system: towards NNLO

TL;DR

This paper discusses the theoretical calculation of the width difference in the $B_s$-$ar B_s$ meson system, focusing on NNLO QCD corrections to improve prediction accuracy.

Contribution

It introduces the calculation of NNLO QCD corrections proportional to $ _f$ for the width difference in the $B_s$ system, reducing theoretical uncertainties.

Findings

Calculated subset of NNLO diagrams proportional to $ _f$

Improved the precision of theoretical predictions

Published results in a referenced paper

Abstract

The width difference $\Delta \Gamma$ among the two mass eigenstates of the $B_s$-$\bar B_s$ system is measured with a precision of 7%. The theory prediction has a larger uncertainty which mainly stems from unknown perturbative higher-order QCD corrections. I discuss the subset of next-to-next-to-leading order diagrams proportional to $\alpha_s^2\, N_f$, where $N_f=5$ is the number of quark flavours. The results are published in [1].