Extracting Vus from Lattice QCD simulations: Recent progress and prospects

TL;DR

This paper reviews recent advances in lattice QCD calculations for determining Vus, highlighting progress in simulations with physical pion mass, multiple dynamical flavors, and improved theoretical methods for extracting form factors.

Contribution

It provides an overview of recent lattice QCD progress in calculating fK/fπ and f+(0), including new computational techniques and theoretical ideas for more precise Vus determination.

Findings

Progress with 2+1 and 2+1+1 dynamical flavors

Simulations at physical pion mass and fine lattices

Development of theoretical methods for cleaner f+ (0) extraction

Abstract

I review the current status of the determination of Vus from a lattice perspective. The recent progress are very impressive: computation with 2 + 1 and 2 + 1 + 1 dynamical flavours, physical pion mass, several fine lattices, different discretisation of the QCD Lagrangian, etc. In this report, intended for non-lattice experts, I give an overview of the situation for the computation of fK /f{\pi} and f+(0), from which Vus and Vud can be extracted. Besides the main features of the new computations, I also present some theoretical ideas developed in the recent years which allow for a cleaner determination of the relevant form factor f+ (0).