doi:10.1103/PhysRevLett.133.221005engAltenmüller, K.Anastassopoulos, V.Arguedas-Cuendis, S.Aune, S.Baier, J.Barth, K.Bräuninger, H.Cantatore, G.Caspers, F.Castel, J.F.Çetin, S.A.Christensen, F.Cogollos, C.Dafni, T.Davenport, M.Decker, T.A.Desch, K.Díez-Ibáñez, D.Döbrich, B.Ferrer-Ribas, E.Fischer, H.Funk, W.Galán, J.García, J.A.Gardikiotis, A.Giomataris, I.Golm, J.Hailey, C.H.Hasinoff, M.D.Hoffmann, D.H.H.Irastorza, I.G.Jacoby, J.Jakobsen, A.C.Jakovcic, K.Kaminski, J.Karuza, M.Kostoglou, S.Krieger, C.Lakic, B.Laurent, J.M.Luzón, G.Malbrunot, C.Margalejo, C.Maroudas, M.Miceli, L.Mirallas, H.Navarro, P.Obis, L.Özbey, A.Özbozduman, K.Papaevangelou, T.Pérez, O.Pivovaroff, M.J.Rosu, M.Ruiz-Chóliz, E.Ruz, J.Schmidt, S.Schumann, M.Semertzidis, Y.K.Solanki, S.K.Stewart, L.Vafeiadis, T.Vogel, J.K.Zioutas, K.New upper limit on the axion-photon coupling with an extended CAST run with a Xe-Based micromegas detectorART-2024-141094Hypothetical axions provide a compelling explanation for dark matter and could be emitted from the hot solar interior. The CERN Axion Solar Telescope has been searching for solar axions via their back conversion to x-ray photons in a 9-T 10-m long magnet directed toward the Sun. We report on an extended run with the International Axion Observatory pathfinder detector, doubling the previous exposure time. The detector was operated with a xenon-based gas mixture for part of the new run, providing technical insights for future configurations. No counts were detected in the 95% signal-encircling region during the new run, while 0.75 were expected. The new data improve the axion-photon coupling limit to 5.8×10−11  GeV−1 at 95% CL (for ma≲0.02  eV), the most restrictive experimental limit to date.2024http://zaguan.unizar.es/record/14727310.1103/PhysRevLett.133.221005http://zaguan.unizar.es/record/147273oai:zaguan.unizar.es:147273info:eu-repo/grantAgreement/EC/H2020/788781/EU/Towards the detection of the axion with the International Axion Observatory/IAXOplusThis project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 788781-IAXOplusinfo:eu-repo/grantAgreement/EC/H2020/802836/EU/Axions and relatives across different mass scales/AxScaleThis project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 802836-AxScaleinfo:eu-repo/grantAgreement/ES/MICINN/PID2019-108122GB-C31info:eu-repo/grantAgreement/ES/MICINN/PID2022-137268NB-C51Physical Review Letters 133, 22 (2024), 221005 [8 pp.]byhttps://creativecommons.org/licenses/by/4.0/deed.esinfo:eu-repo/semantics/openAccess