Leptonic Meson Decays into Invisible ALP

Jorge Alda Gallo; Alfredo Walter Mario Guerrera; Siannah Peñaranda; Stefano Rigolin

doi:10.1016/j.nuclphysb.2022.115791

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arXiv · 2111.02536

Leptonic Meson Decays into Invisible ALP

Jorge Alda Gallo·Alfredo Walter Mario Guerrera·Siannah Peñaranda·Stefano Rigolin

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Abstract

The theoretical calculation of pseudo-scalar leptonic decay widths into an invisible ALP, $M \to \ell\, \nu_\ell\, a$, is reviewed. Assuming generic flavour-conserving ALP couplings to SM fermions and a generic ALP mass, $m_a$, the latest experimental results for pseudo-scalar leptonic decays are used to provide updated bounds on the ALP-fermion Lagrangian sector. Constrains on the ALP-quark couplings obtained from these channels are not yet competitive with the ones derived from FCNC processes, like $M\to P\,a$ decays. These leptonic decays can, however, provide the most stringent model-independent upper bounds on ALP-leptons couplings for $m_a$ in the (sub)-GeV range.

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Jorge Alda Gallo, Alfredo Walter Mario Guerrera, Siannah Peñaranda, Stefano Rigolin. 2021-11-03. Leptonic Meson Decays into Invisible ALP. https://doi.org/10.1016/j.nuclphysb.2022.115791

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