163791 20251107115328.0 doi 10.1103/18sn-hxtb sideral 145851 ART-2025-145851 eng Ruz, J. (orcid)0000-0002-3253-7027 NuSTAR as an Axion Helioscope 2025 We present a novel approach to investigating axions and axionlike particles by studying their potential conversion into x-rays within the Sun’s atmospheric magnetic field. Utilizing high-sensitivity data from the nuclear spectroscopic telescope array (NuSTAR) collected during the 2020 solar minimum, along with advanced solar atmospheric magnetic field models, we establish a new limit on the axion-photon coupling strength ⁢≲7.3×10−12  GeV−1 at 95% CL for axion masses ≲4×10−7  eV. This constraint surpasses current ground-based experimental limits, studying previously unexplored regions of the axion-photon coupling parameter space up to masses of ≲3.4 ×10−4  eV. These findings mark a significant advancement in our ability to probe axion properties and strengthen indirect searches for dark matter candidates. Access copy available to the general public Unrestricted info:eu-repo/semantics/openAccess by https://creativecommons.org/licenses/by/4.0/deed.es info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Todarello, E. Vogel, J. K. (orcid)0000-0002-5850-5517 Rodriguez Candón, F. Universidad de Zaragoza Giannotti, M. Universidad de Zaragoza (orcid)0000-0001-9823-6262 Grefenstette, B. Hudson, H.S. Hannah, I. G. García Irastorza, I. Universidad de Zaragoza (orcid)0000-0003-1163-1687 Kim, C. S. Regis, M. Smith, D. M. Taoso, M. Trujillo Bueno, J. 2004 038 Universidad de Zaragoza Dpto. Física Teórica Área Astronomía y Astrofísica 2004 390 Universidad de Zaragoza Dpto. Física Teórica Área Física Atóm.Molec.y Nucl. 135, 141001 (2025), 7 Phys. rev. lett. Physical Review Letters 0031-9007 576841 http://zaguan.unizar.es/record/163791/files/texto_completo.pdf Versión publicada 2966699 http://zaguan.unizar.es/record/163791/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:163791 articulos driver 2025-11-07-10:24:44 ARTICLE