Leptonic ALP portal to the dark sector
Giovanni Armando, Paolo Panci, J. M. Weiss, Robert Ziegler
Abstract
We discuss the leptonic axionlike particle (ALP) portal as a simple scenario that connects observed discrepancies in anomalous magnetic moments to the dark matter relic abundance. In this framework an axionlike particle in the multi-MeV range couples to SM leptons and a dark matter (DM) fermion, with mass above the ALP mass but below 1 GeV. The ALP contributes to <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mo stretchy="false">(</a:mo><a:mi>g</a:mi><a:mo>−</a:mo><a:mn>2</a:mn><a:msub><a:mo stretchy="false">)</a:mo><a:mi>μ</a:mi></a:msub></a:math> and <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mo stretchy="false">(</e:mo><e:mi>g</e:mi><e:mo>−</e:mo><e:mn>2</e:mn><e:msub><e:mo stretchy="false">)</e:mo><e:mi>e</e:mi></e:msub></e:math> dominantly through two-loop Barr-Zee diagrams, while the DM abundance is generated by <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:mi>p</i:mi></i:math>-wave annihilation to ALP pairs. Constraints from beam-dump experiments, colliders, and cosmic microwave background probes are very stringent, and restrict the viable parameter space to a rather narrow region that will be tested in the near future. Published by the American Physical Society 2024