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arXiv · 2112.11823

Near-Physical Point Lattice Calculation of Isospin-Breaking Corrections to $K_{\ell2}/\pi_{\ell2}$

Andrew Zhen Ning Yong·Peter Boyle·Matteo Di Carlo·Felix Erben·Vera Gülpers·Maxwell T. Hansen·Tim Harris·Nils Hermansson-Truedsson·Raoul Hodgson·Andreas Jüttner·Antonin Portelli·James Richings
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Abstract

In recent years, lattice determinations of non-perturbative quantities such as $f_K$ and $f_\pi$, which are relevant for $V_{us}$ and $V_{ud}$, have reached an impressive precision of $\mathcal{O}(1\%)$ or better. To make further progress, electromagnetic and strong isospin breaking effects must be included in lattice QCD simulations. We present the status of the RBC/UKQCD lattice calculation of isospin-breaking corrections to light meson leptonic decays. This computation is performed in a (2+1)-flavor QCD simulation using Domain Wall Fermions with near-physical quark masses. The isospin-breaking effects are implemented via a perturbative expansion of the action in $\alpha$ and $(m_u-m_d)$. In this calculation, we work in the electro-quenched approximation and the photons are implemented in the Feynman gauge and $\text{QED}_\text{L}$ formulation.

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Andrew Zhen Ning Yong, Peter Boyle, Matteo Di Carlo, Felix Erben, Vera Gülpers, Maxwell T. Hansen, Tim Harris, Nils Hermansson-Truedsson, Raoul Hodgson, Andreas Jüttner, Antonin Portelli, James Richings. 2021-12-22. Near-Physical Point Lattice Calculation of Isospin-Breaking Corrections to $K_{\ell2}/\pi_{\ell2}$. https://arxiv.org/abs/2112.11823

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