TY - JOUR

T1 - Isospin-breaking corrections to light-meson leptonic decays from lattice simulations at physical quark masses

AU - Boyle, Peter

AU - Di Carlo, Matteo

AU - Erben, Felix

AU - Gülpers, Vera

AU - Hansen, Maxwell T.

AU - Harris, Tim

AU - Hermansson-Truedsson, Nils

AU - Hodgson, Raoul

AU - Jüttner, Andreas

AU - hÓgáin, Fionn

AU - Portelli, Antonin

AU - Richings, James

AU - Yong, Andrew Zhen Ning

PY - 2023/3

Y1 - 2023/3

N2 - The decreasing uncertainties in theoretical predictions and experimental measurements of several hadronic observables related to weak processes, which in many cases are now smaller than O(1%), require theoretical calculations to include subleading corrections that were neglected so far. Precise determinations of leptonic and semi-leptonic decay rates, including QED and strong isospin-breaking effects, can play a central role in solving the current tensions in the first-row unitarity of the CKM matrix. In this work we present the first RBC/UKQCD lattice calculation of the isospin-breaking corrections to the ratio of leptonic decay rates of kaons and pions into muons and neutrinos. The calculation is performed at fixed lattice spacing (a−1 ≃ 1.730 GeV) on a 483× 96 volume with Nf = 2 + 1 dynamical quarks close to the physical point and domain wall fermions in the Möbius formulation are employed. Long-distance QED interactions are included according to the QEDL prescription and the crucial role of finite-volume electromagnetic corrections in the determination of leptonic decay rates, which produce a large systematic uncertainty, is extensively discussed. Finally, we study the different sources of uncertainty on |Vus|/|Vud| and observe that, if finite-volume systematics can be reduced, the error from isospin-breaking corrections is potentially sub-dominant in the final precision of the ratio of the CKM matrix elements.

AB - The decreasing uncertainties in theoretical predictions and experimental measurements of several hadronic observables related to weak processes, which in many cases are now smaller than O(1%), require theoretical calculations to include subleading corrections that were neglected so far. Precise determinations of leptonic and semi-leptonic decay rates, including QED and strong isospin-breaking effects, can play a central role in solving the current tensions in the first-row unitarity of the CKM matrix. In this work we present the first RBC/UKQCD lattice calculation of the isospin-breaking corrections to the ratio of leptonic decay rates of kaons and pions into muons and neutrinos. The calculation is performed at fixed lattice spacing (a−1 ≃ 1.730 GeV) on a 483× 96 volume with Nf = 2 + 1 dynamical quarks close to the physical point and domain wall fermions in the Möbius formulation are employed. Long-distance QED interactions are included according to the QEDL prescription and the crucial role of finite-volume electromagnetic corrections in the determination of leptonic decay rates, which produce a large systematic uncertainty, is extensively discussed. Finally, we study the different sources of uncertainty on |Vus|/|Vud| and observe that, if finite-volume systematics can be reduced, the error from isospin-breaking corrections is potentially sub-dominant in the final precision of the ratio of the CKM matrix elements.

KW - CKM Parameters

KW - Hadronic Matrix Elements and Weak Decays

KW - Lattice QCD

KW - Standard Model Parameters

U2 - 10.1007/JHEP02(2023)242

DO - 10.1007/JHEP02(2023)242

M3 - Article

AN - SCOPUS:85149208312

SN - 1029-8479

VL - 2023

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 2

M1 - 242

ER -