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arXiv · 2010.15846

Selective enhancement of the QCD axion couplings

Luc Darmé·Luca Di Luzio·Maurizio Giannotti·Enrico Nardi
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Abstract

We present a mechanism wherein the QCD axion coupling to nucleons, photons, or electrons, can be enhanced selectively without increasing the axion mass. We focus in particular on the axion-nucleon couplings, that are generally considered to be largely model-independent, and we show how nucleophilic axion models can be constructed. We discuss the implications of a nucleophilic axion for astrophysics, cosmology and laboratory searches. We present a model with enhanced axion couplings to nucleons and photons that can provide an excellent fit to the anomalous emission of hard X-rays recently observed from a group of nearby neutron stars, and we argue that such a scenario can be thoroughly tested in forthcoming axion-search experiments.

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Luc Darmé, Luca Di Luzio, Maurizio Giannotti, Enrico Nardi. 2020-10-29. Selective enhancement of the QCD axion couplings. https://doi.org/10.1103/physrevd.103.015034

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