000168670 001__ 168670 000168670 005__ 20260213191049.0 000168670 0247_ $$2doi$$a10.1088/1475-7516/2009/02/008 000168670 0248_ $$2sideral$$a63699 000168670 037__ $$aART-2009-63699 000168670 041__ $$aeng 000168670 100__ $$aArik, E. 000168670 245__ $$aProbing eV-Scale Axions with CAST 000168670 260__ $$c2009 000168670 5203_ $$aWe have searched for solar axions or other pseudoscalar particles that couple to two photons by using the CERN Axion Solar Telescope (CAST) setup. Whereas we previously have reported results from CAST with evacuated magnet bores (Phase I), setting limits on lower mass axions, here we report results from CAST where the magnet bores were filled with 4He gas (Phase II) of variable pressure. The introduction of gas generates a refractive photon mass mγ, thereby achieving the maximum possible conversion rate for those axion masses ma that match mγ. With 160 different pressure settings we have scanned ma up to about 0.4 eV, taking approximately 2 h of data for each setting. From the absence of excess x-rays when the magnet was pointing to the Sun, we set a typical upper limit on the axion-photon coupling of gaγ≲2.2 × 10−10 GeV−1 at 95% CL for ma≲0.4 eV, the exact result depending on the pressure setting. The excluded parameter range covers realistic axion models with a Peccei-Quinn scale in the neighborhood of fa ∼ 107 GeV. Currently in the second part of CAST Phase II, we are searching for axions with masses up to about 1.2 eV using 3He as a buffer gas. 000168670 540__ $$9info:eu-repo/semantics/closedAccess$$aAll rights reserved$$uhttp://www.europeana.eu/rights/rr-f/ 000168670 590__ $$a6.502$$b2009 000168670 591__ $$aPHYSICS, PARTICLES & FIELDS$$b3 / 27 = 0.111$$c2009$$dQ1$$eT1 000168670 591__ $$aASTRONOMY & ASTROPHYSICS$$b6 / 52 = 0.115$$c2009$$dQ1$$eT1 000168670 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000168670 700__ $$aAune, S. 000168670 700__ $$aAutiero, D. 000168670 700__ $$aBarth, K. 000168670 700__ $$aBelov, A. 000168670 700__ $$aBeltran, B. 000168670 700__ $$aBorghi, S. 000168670 700__ $$aBourlis, G. 000168670 700__ $$aBoydag, F. S. 000168670 700__ $$aBraeuninger, H. 000168670 700__ $$aCarmona, J. M. 000168670 700__ $$0(orcid)0000-0002-6948-5101$$aCebrian, S.$$uUniversidad de Zaragoza 000168670 700__ $$aCetin, S. A. 000168670 700__ $$aCollar, J. I. 000168670 700__ $$0(orcid)0000-0002-8921-910X$$aDafni, T.$$uUniversidad de Zaragoza 000168670 700__ $$aDavenport, M. 000168670 700__ $$aDi Lella, L. 000168670 700__ $$aDogan, O. B. 000168670 700__ $$aEleftheriadis, C. 000168670 700__ $$aElias, N. 000168670 700__ $$aFanourakis, G. 000168670 700__ $$aFerrer-Ribas, E. 000168670 700__ $$aFischer, H. 000168670 700__ $$aFriedrich, P. 000168670 700__ $$aFranz, J. 000168670 700__ $$aGalan, J. 000168670 700__ $$aGeralis, T. 000168670 700__ $$aGiomataris, I. 000168670 700__ $$aGninenko, S. 000168670 700__ $$0(orcid)0000-0002-1770-8940$$aGomez, H.$$uUniversidad de Zaragoza 000168670 700__ $$aHartmann, R. 000168670 700__ $$aHasinoff, M. 000168670 700__ $$aHeinsius, F. H. 000168670 700__ $$aHikmet, I. 000168670 700__ $$aHoffmann, D. H. H. 000168670 700__ $$0(orcid)0000-0003-1163-1687$$aIrastorza, I. G.$$uUniversidad de Zaragoza 000168670 700__ $$aJacoby, J. 000168670 700__ $$aJakovcic, K. 000168670 700__ $$aKang, D. 000168670 700__ $$aKoenigsmann, K. 000168670 700__ $$aKotthaus, R. 000168670 700__ $$aKrcmar, M. 000168670 700__ $$aKousouris, K. 000168670 700__ $$aKuster, M. 000168670 700__ $$aLakic, B. 000168670 700__ $$aLasseur, C. 000168670 700__ $$aLiolios, A. 000168670 700__ $$aLjubicic, A. 000168670 700__ $$aLutz, G. 000168670 700__ $$0(orcid)0000-0002-5352-1884$$aLuzon, G.$$uUniversidad de Zaragoza 000168670 700__ $$aMiller, D. 000168670 700__ $$aMorales, J.$$uUniversidad de Zaragoza 000168670 700__ $$aNiinikoski, T. 000168670 700__ $$aNordt, A. 000168670 700__ $$aOrtiz, A. 000168670 700__ $$aPapaevangelou, T. 000168670 700__ $$aPivovaroff, M. J. 000168670 700__ $$aPlacci, A. 000168670 700__ $$aRaffelt, G. 000168670 700__ $$aRiege, H. 000168670 700__ $$aRodriguez, A. 000168670 700__ $$0(orcid)0000-0002-3253-7027$$aRuz, J.$$uUniversidad de Zaragoza 000168670 700__ $$aSavvidis, I. 000168670 700__ $$aSemertzidis, Y. 000168670 700__ $$aSerpico, P. 000168670 700__ $$aSoufli, R. 000168670 700__ $$aStewart, L. 000168670 700__ $$aVan Bibber, K. 000168670 700__ $$0(orcid)0000-0003-0228-7589$$aVillar, J.$$uUniversidad de Zaragoza 000168670 700__ $$aVogel, J. 000168670 700__ $$aWalckiers, L. 000168670 700__ $$aZioutas, K. 000168670 7102_ $$12004$$2390$$aUniversidad de Zaragoza$$bDpto. Física Teórica$$cÁrea Física Atóm.Molec.y Nucl. 000168670 773__ $$g2, 008 (2009), 1-15$$pJ. Cosmol. Astropart. Phys.$$tJournal of Cosmology and Astroparticle Physics$$x1475-7516 000168670 8564_ $$s927629$$uhttps://zaguan.unizar.es/record/168670/files/texto_completo.pdf$$yVersión publicada 000168670 8564_ $$s1994803$$uhttps://zaguan.unizar.es/record/168670/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000168670 909CO $$ooai:zaguan.unizar.es:168670$$particulos$$pdriver 000168670 951__ $$a2026-02-13-18:28:07 000168670 980__ $$aARTICLE