We study how the coupling between axion-like particles (ALPs) and matter can be obtained at the level of on-shell scattering amplitudes. We identify three conditions that allow us to compute amplitudes that correspond to shift-symmetric Lagrangians, at the level of operators with dimension 5 or higher, and we discuss how they relate and extend the Adler’s zero condition. These conditions are necessary to reduce the number of coefficients consistent with the little-group scaling to the one expected from the Lagrangian approach. We also show how our formalism easily explains that the dimension-5 interaction involving one ALP and two massless spin-1 bosons receive corrections from higher order operators only when the ALP has a non-vanishing mass. As a direct application of our results, we perform a phenomenological study of the inelastic scattering ℓ+ℓ− → ϕh (with ℓ± two charged leptons, ϕ the ALP and h the Higgs boson) for which, as a result of the structure of the 3-point and 4-point amplitudes, dimension-7 operators can dominate over the dimension-5 ones well before the energy reaches the cutoff of the theory.

ALPs, the on-shell way / Bertuzzo, E.; Grojean, C.; Salla, G. M.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - 2024:5(2024), pp. 175-226. [10.1007/JHEP05(2024)175]

ALPs, the on-shell way

Bertuzzo E.;
2024

Abstract

We study how the coupling between axion-like particles (ALPs) and matter can be obtained at the level of on-shell scattering amplitudes. We identify three conditions that allow us to compute amplitudes that correspond to shift-symmetric Lagrangians, at the level of operators with dimension 5 or higher, and we discuss how they relate and extend the Adler’s zero condition. These conditions are necessary to reduce the number of coefficients consistent with the little-group scaling to the one expected from the Lagrangian approach. We also show how our formalism easily explains that the dimension-5 interaction involving one ALP and two massless spin-1 bosons receive corrections from higher order operators only when the ALP has a non-vanishing mass. As a direct application of our results, we perform a phenomenological study of the inelastic scattering ℓ+ℓ− → ϕh (with ℓ± two charged leptons, ϕ the ALP and h the Higgs boson) for which, as a result of the structure of the 3-point and 4-point amplitudes, dimension-7 operators can dominate over the dimension-5 ones well before the energy reaches the cutoff of the theory.
2024
2024
5
175
226
ALPs, the on-shell way / Bertuzzo, E.; Grojean, C.; Salla, G. M.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - 2024:5(2024), pp. 175-226. [10.1007/JHEP05(2024)175]
Bertuzzo, E.; Grojean, C.; Salla, G. M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1340891
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