First Lattice Calculation of the QED Corrections to Leptonic Decay Rates

Open Access

First Lattice Calculation of the QED Corrections to Leptonic Decay Rates

D. Giusti, V. Lubicz, C. Tarantino, G. Martinelli, C. T. Sachrajda, F. Sanfilippo, S. Simula, and N. Tantalo

Phys. Rev. Lett. 120, 072001 – Published 13 February 2018

Abstract

The leading-order electromagnetic and strong isospin-breaking corrections to the ratio of $K_{μ 2}$ and $π_{μ 2}$ decay rates are evaluated for the first time on the lattice, following a method recently proposed. The lattice results are obtained using the gauge ensembles produced by the European Twisted Mass Collaboration with $N_{f} = 2 + 1 + 1$ dynamical quarks. Systematic effects are evaluated and the impact of the quenched QED approximation is estimated. Our result for the correction to the tree-level $K_{μ 2} / π_{μ 2}$ decay ratio is $- 1.22 (16) %$ , to be compared to the estimate of $- 1.12 (21) %$ based on chiral perturbation theory and adopted by the Particle Data Group.

Received 27 December 2017

DOI:https://doi.org/10.1103/PhysRevLett.120.072001

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society