Abstract
Axion production from astrophysical bodies is a topic incontinuous development, because of theoretical progress in the estimate of stellar emission ratesand, especially, because of improved stellar observations.We carry out a comprehensive analysis of the most informativeastrophysics data, revisiting the bounds on axion couplings to photons,nucleons and electrons, and reassessing the significance ofvarious hints of anomalous stellar energy losses.We confront the performance of various theoretical constructions inaccounting for these hints, while complyingwith the observational limits on axion couplings.We identify the most favorable models, and the regions in the mass/couplings parameter space which are preferred by the global fit. Finally, we scrutinize the discovery potential for such models at upcoming helioscopes, namely IAXO and its scaled versions.
Highlights
The most elegant solution to the strong CP problem, the so called Peccei-Quinn (PQ) mechanism [1, 2], implies the existence of the axion [3, 4], which provides one of the best particle physics candidates for cold dark matter (DM) [5,6,7]
Astrophysical limits have been derived from the non-observation of axion emission from our Sun, from the concordance between the prediction of stellar evolution codes and direct observations of star distributions in the color-magnitude diagram (CMD) for evolved low-mass star populations, such as red giant branch (RGB) and horizontal-branch (HB) stars in globular clusters, from limits on cooling rates of white dwarfs (WD) and neutron stars (NS), and from the duration of the neutrino burst from the collapsed core of supernova (SN) SN 1987A
Taking into account gauge group factors one gets [22]: yq < 16π/3 for the Yukawa couplings of the quarks and y < 4 2π for the charged leptons, where yq, are the Yukawa couplings defined in the multi-Higgs doublet theory that have to be matched with their SM counterparts in order to extract a bound on the electroweak vacuum angles
Summary
The most elegant solution to the strong CP problem, the so called Peccei-Quinn (PQ) mechanism [1, 2], implies the existence of the axion [3, 4], which provides one of the best particle physics candidates for cold dark matter (DM) [5,6,7]. The supernova and neutron star bounds have been updated in the last few years [15,16,17,18,19] In light of these recent progresses, it seems timely to revise the global analysis of the stellar bounds/hints on axions, and to provide updated regions in parameter space where the experimental search may be motivated. This is the task we address in this paper. A detailed calculation of the axion-photon couplings for the non-universal DFSZ models is presented in Appendix A
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
