Stellar Evolution and Axion-Like Particles: New Constraints and Hints from Globular Clusters in the GAIA DR3 Data

Abstract

Axion-like particles (ALPs) are hypothetical pseudoscalar bosons, natural in extensions of the Standard Model. Their interactions with ordinary matter and radiation are suppressed, making it challenging to detect them in laboratory experiments. However, these particles, produced within stellar interiors, can provide an additional mechanism for energy loss, potentially influencing stellar evolution. Prominent methods for searching for such effects involve measuring the properties of red giants and helium-burning stars in globular clusters (GCs). Here we use published catalogs of stars selected as members of seven GCs on the basis of p-arallaxes and proper motions measured by Gaia (Data Release 3). Making use of previously derived theoretical relations and the new data, we find the upper limit on the ALP-electron coupling, \({{g}_{{ae}}} < 5.2 \times {{10}^{{ - 14}}}\) (95% CL), and an indication (\(3.3\sigma \)) to nonzero ALP-photon coupling, \({{g}_{{a\gamma }}} = (6.5_{{ - 1.3}}^{{ + 1.1}}) \times {{10}^{{ - 11}}}\) GeV^–1. Given the precision of contemporary observational data, it is imperative to refine ALP constraints through more sophisticated analyses, which will be explored in detail elsewhere.