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arXiv · 2212.04709

Isospin-breaking corrections to light leptonic decays in lattice QCD+QED at the physical point

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

We report on the physical-point RBC/UKQCD calculation of the leading isospin-breaking corrections to light-meson leptonic decays. This is highly relevant for future precision tests in the flavour physics sector, in particular the first-row unitarity of the Cabibbo-Kobayashi-Maskawa matrix containing the elements $V_{us}$ and $V_{ud}$. The simulations were performed using Domain-Wall fermions for $2+1$ flavours, and with isospin-breaking effects included perturbatively in the path integral through order $\alpha$ and $(m_u - m_d)/\Lambda _{\mathrm{QCD}}$. We use QED$_{\mathrm{L}}$ for the inclusion of electromagnetism, and discuss here the non-locality of this prescription which has significant impact on the infinite-volume extrapolation.

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Peter Boyle, Matteo Di Carlo, Felix Erben, Vera Gülpers, Maxwell T. Hansen, Tim Harris, Nils Hermansson-Truedsson, Raoul Hodgson, Andreas Jüttner, Fionn Ó hÓgáin, Antonin Portelli, James Richings, Andrew Z. N. Yong. 2022-12-09. Isospin-breaking corrections to light leptonic decays in lattice QCD+QED at the physical point. https://arxiv.org/abs/2212.04709

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