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arXiv · 2206.04061

$a \to \pi \pi \pi$ decay at next-to-leading order in chiral perturbation theory

Luca Di Luzio·Gioacchino Piazza
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Abstract

We discuss the construction of the two-flavour axion-pion effective Lagrangian at the next-to-leading order (NLO) in chiral perturbation theory and present, as a phenomenological application, the calculation of the decay rate of a GeV-scale axion-like particle via the channel $a \to \pi\pi\pi$. Through the NLO calculation, we assess the range of validity of the effective field theory and show that the chiral expansion breaks down just above the kinematic threshold. Alternative non-perturbative approaches are called for in order to extend the chiral description of axion-pion interactions.

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Luca Di Luzio, Gioacchino Piazza. 2022-06-08. $a \to \pi \pi \pi$ decay at next-to-leading order in chiral perturbation theory. https://doi.org/10.1007/jhep12(2022)041

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