Two-Loop Effective Theory Analysis of $π$ $(K) \to e {\bar{ν}}_{e} [γ]$ Branching Ratios

Publisher Website

6 December 2007

journal article
research article
Published by American Physical Society (APS) in Physical Review Letters

Vol. 99 (23) , 231801
https://doi.org/10.1103/physrevlett.99.231801

Abstract

We study the ratios

R_{e / μ}^{(P)} \equiv Γ (P \to e {\bar{ν}}_{e} [γ]) / Γ (P \to μ {\bar{ν}}_{μ} [γ])

(

P = π

,

K

) in Chiral Perturbation Theory to order

e^{2} p^{4}

. We complement the two-loop effective theory results with a matching calculation of the counterterm, finding

R_{e / μ}^{(π)} = (1.2352 \pm 0.0001) \times 10^{- 4}

and

R_{e / μ}^{(K)} = (2.477 \pm 0.001) \times 10^{- 5}

.

Keywords

BRANCHING RATIO

All Related Versions

Version 1, 2007-07-23, ArXiv

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