Journal article

Consistent Treatment of Axions in the Weak Chiral Lagrangian

Martin Bauer, Matthias Neubert, Sophie Renner, Marvin Schnubel, Andrea Thamm

PHYSICAL REVIEW LETTERS | AMER PHYSICAL SOC | Published : 2021

Abstract

We present a consistent implementation of weak decays involving an axion or axionlike particle in the context of an effective chiral Lagrangian. We argue that previous treatments of such processes have used an incorrect representation of the flavor-changing quark currents in the chiral theory. As an application, we derive model-independent results for the decays K^{-}→π^{-}a and π^{-}→e^{-}ν[over ¯]_{e}a at leading order in the chiral expansion and for arbitrary axion couplings and mass. In particular, we find that the K^{-}→π^{-}a branching ratio is almost 40 times larger than previously estimated.

University of Melbourne Researchers

Grants

Awarded by Cluster of Excellence PRISMA+ - German Research Foundation (DFG) within the German Excellence Strategy


Funding Acknowledgements

M. N. thanks Gino Isidori, the particle theory group at Zurich University and the Pauli Center for hospitality during a sabbatical stay. This research has been supported by the Cluster of Excellence PRISMA+ funded by the German Research Foundation (DFG) within the German Excellence Strategy (Project No. 39083149). S. R. acknowledges support from the INFN grant SESAMO.