We study the effects of exceptionally light QCD axions on the stellar configuration of white dwarfs. At finite baryon density, the nonderivative coupling of the axion to nucleons displaces the axion from its invacuum minimum, which implies a reduction of the nucleon mass. This dramatically alters the composition of stellar remnants. In particular, the modifications of the mass-radius relationship of white dwarfs allow us to probe large regions of unexplored parameter space without requiring that axions are dark matter.
Details
Title
White dwarfs as a probe of exceptionally light QCD axions
Grant
Collaborative Research Center SFB1258 Munich Institute for Astro- and Particle Physics (MIAPP) Excellence Cluster ORIGINS - Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) MCIN/AEI: 200020-18867 ESF Investing in your future Spanish Agencia Estatal de Investigacion Swiss National Science Foundation: 2020300 NSF-BSF: 390783311 ISF: CEX2020- 001007-S Azrieli foundation BSF RYC-2020-028992-I 2018683 482/20