TY  - EJOUR
AU  - Bertuzzo, Enrico
AU  - Grojean, Christophe
AU  - Salla, Gabriel M.
TI  - ALPs, the on-shell way
IS  - DESY-23-090
M1  - PUBDB-2023-03958
M1  - DESY-23-090
M1  - arXiv:2311.16253
M1  - CERN-TH-2023-202
M1  - HU-EP-23/21
PY  - 2023
N1  - 32 pages + appendices
AB  - 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 <i>l</i><sup>+</sup><i>l</i><sup>−</sup> → ϕh (with <i>l</i><sup>±</sup> 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.
KW  - dimension, 5 (INSPIRE)
KW  - operator, higher-order (INSPIRE)
KW  - scattering amplitude, on-shell (INSPIRE)
KW  - lepton (INSPIRE)
KW  - axion-like particles (INSPIRE)
KW  - inelastic scattering (INSPIRE)
KW  - scaling (INSPIRE)
KW  - Higgs particle (INSPIRE)
KW  - structure (INSPIRE)
LB  - PUB:(DE-HGF)25
DO  - DOI:10.3204/PUBDB-2023-03958
UR  - https://bib-pubdb1.desy.de/record/586561
ER  -