First Lattice Calculation of the QED Corrections to Leptonic Decay Rates
Abstract
The leadingorder electromagnetic and strong isospinbreaking 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 treelevel 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.
 Publication:

Physical Review Letters
 Pub Date:
 February 2018
 DOI:
 10.1103/PhysRevLett.120.072001
 arXiv:
 arXiv:1711.06537
 Bibcode:
 2018PhRvL.120g2001G
 Keywords:

 High Energy Physics  Lattice;
 High Energy Physics  Experiment;
 High Energy Physics  Phenomenology
 EPrint:
 5 pages, 6 figures