Abstract
The leading-order electromagnetic and strong isospin-breaking corrections to the ratio of K_{μ2} and π_{μ2} 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_{μ2}/π_{μ2} 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.
Highlights
Dipartimento di Fisica, Universitadi Roma La Sapienza and INFN Sezione di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy
The leading-order electromagnetic and strong isospin-breaking corrections to the ratio of Kμ2 and πμ2 decay rates are evaluated for the first time on the lattice, following a method recently proposed
In this Letter we focus on the ratio of the inclusive decay rates of kaons and pions into muons, namely, ΓðKμ2Þ Γðπμ2Þ
Summary
Dipartimento di Fisica, Universitadi Roma La Sapienza and INFN Sezione di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy. Our result for the correction to the tree-level Kμ2/πμ2 decay ratio is −1.22ð16Þ%, to be compared to the estimate of −1.12ð21Þ% based on chiral perturbation theory and adopted by the Particle Data Group.
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