New solar axion search in CAST with $^4$He filling

Arik, M.; Liolios, A.; Collar, J.I.; Bräuninger, H.; Ortega, I.; Galán, J.; Da Riva, E.; Dermenev, A.; Shilon, I.; Gninenko, S.; Elias, N.; Ljubičić, A.; Geralis, T.; Neff, S.; Raffelt, G.; Belov, A.; Savvidis, I.; Rodríguez, A.; Lakić, B.; Dafni, T.; Tomás, A.; Vafeiadis, T.; Irastorza, I.G.; Pivovaroff, M.J.; Carmona, J.M.; Fanourakis, G.; Jacoby, J.; Davenport, M.; Laurent, J.M.; Ferrer-Ribas, E.; Gazis, E.N.; García, J. A.; Burwitz, V.; Yildiz, S.C.; Gardikiotis, A.; Hasinoff, M.D.; Nordt, A.; Ruz, J.; Vogel, J.K.; Cetin, S.A.; Solanki, S.K.; Jakovčić, K.; Cantatore, G.; Kavuk, M.; Zioutas, K.; Aune, S.; Papaevangelou, T.; Rosu, M.; Stewart, L.; Karuza, M.; Garza, J.G.; Villar, J.; Eleftheriadis, C.; Georgiopoulou, E.; Iguaz, F.J.; Krčmar, M.; Gómez Marzoa, M.; Giomataris, I.; Bremer, J.; Niinikoski, T.; Kuster, M.; Barth, K.; Luzón, G.; Hoffmann, D.H.H.

doi:10.1103/PhysRevD.92.021101

Article
Report number	arXiv:1503.00610
Title	New solar axion search in CAST with $^4$He filling
Author(s)	Arik, M. (Dogus U., Kadikoy) ; Aune, S. (DAPNIA, Saclay) ; Barth, K. (CERN) ; Belov, A. (Moscow, INR) ; Bräuninger, H. (Garching, Max Planck Inst., MPE) ; Bremer, J. (CERN) ; Burwitz, V. (Garching, Max Planck Inst., MPE) ; Cantatore, G. (INFN, Trieste) ; Carmona, J.M. (Zaragoza U.) ; Cetin, S.A. (Dogus U., Kadikoy) ; Collar, J.I. (Chicago U., EFI) ; Da Riva, E. (CERN) ; Dafni, T. (Zaragoza U.) ; Davenport, M. (CERN) ; Dermenev, A. (Moscow, INR) ; Eleftheriadis, C. (Aristotle U., Thessaloniki) ; Elias, N. (CERN) ; Fanourakis, G. (Democritos Nucl. Res. Ctr.) ; Ferrer-Ribas, E. (DAPNIA, Saclay) ; Galán, J. (IRFU, Saclay) ; García, J. A. (Zaragoza U.) ; Gardikiotis, A. (Patras U.) ; Garza, J.G. (Zaragoza U.) ; Gazis, E.N. (Natl. Tech. U., Athens) ; Geralis, T. (Democritos Nucl. Res. Ctr.) ; Georgiopoulou, E. (Patras U.) ; Giomataris, I. (DAPNIA, Saclay) ; Gninenko, S. (Moscow, INR) ; Gómez Marzoa, M. (CERN) ; Hasinoff, M.D. (British Columbia U.) ; Hoffmann, D.H.H. (Darmstadt, Tech. Hochsch.) ; Iguaz, F.J. (Zaragoza U.) ; Irastorza, I.G. (Zaragoza U.) ; Jacoby, J. (Frankfurt U.) ; Jakovčić, K. (Boskovic Inst., Zagreb) ; Karuza, M. (INFN, Trieste ; Rijeka U.) ; Kavuk, M. (Dogus U., Kadikoy) ; Krčmar, M. (Boskovic Inst., Zagreb) ; Kuster, M. (Garching, Max Planck Inst., MPE ; Darmstadt, Tech. Hochsch.) ; Lakić, B. (Boskovic Inst., Zagreb) ; Laurent, J.M. (CERN) ; Liolios, A. (Aristotle U., Thessaloniki) ; Ljubičić, A. (Boskovic Inst., Zagreb) ; Luzón, G. (Zaragoza U.) ; Neff, S. (Darmstadt, Tech. Hochsch.) ; Niinikoski, T. (CERN) ; Nordt, A. (Garching, Max Planck Inst., MPE ; Darmstadt, Tech. Hochsch.) ; Ortega, I. (Zaragoza U. ; CERN) ; Papaevangelou, T. (DAPNIA, Saclay) ; Pivovaroff, M.J. (LLNL, Livermore) ; Raffelt, G. (Munich, Max Planck Inst.) ; Rodríguez, A. (Zaragoza U.) ; Rosu, M. (Darmstadt, Tech. Hochsch.) ; Ruz, J. (LLNL, Livermore) ; Savvidis, I. (Aristotle U., Thessaloniki) ; Shilon, I. (Zaragoza U. ; CERN) ; Solanki, S.K. (Gottingen, Max Planck Inst.) ; Stewart, L. (CERN) ; Tomás, A. (Zaragoza U.) ; Vafeiadis, T. (CERN ; Aristotle U., Thessaloniki ; Patras U.) ; Villar, J. (Zaragoza U.) ; Vogel, J.K. (LLNL, Livermore) ; Yildiz, S.C. (Dogus U., Kadikoy) ; Zioutas, K. (CERN ; Patras U.)
Publication	2015-07-28
Imprint	02 Mar 2015
Number of pages	6
Note	Comments: CAST Collaboration 6 pages 2 figures CAST Collaboration 6 pages 3 figures
In:	Phys. Rev. D 92 (2015) 021101(R)
DOI	10.1103/PhysRevD.92.021101
Subject category	Particle Physics - Experiment
Abstract	The CERN Axion Solar Telescope (CAST) searches for $a\to\gamma$ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. Two parallel magnet bores can be filled with helium of adjustable pressure to match the X-ray refractive mass $m_\gamma$ to the axion search mass $m_a$. After the vacuum phase (2003--2004), which is optimal for $m_a\lesssim0.02$ eV, we used $^4$He in 2005--2007 to cover the mass range of 0.02--0.39 eV and $^3$He in 2009--2011 to scan from 0.39--1.17 eV. After improving the detectors and shielding, we returned to $^4$He in 2012 to investigate a narrow $m_a$ range around 0.2 eV ("candidate setting" of our earlier search) and 0.39--0.42 eV, the upper axion mass range reachable with $^4$He, to "cross the axion line" for the KSVZ model. We have improved the limit on the axion-photon coupling to $g_{a\gamma}< 1.47\times10^{-10} {\rm GeV}^{-1}$ (95% C.L.), depending on the pressure settings. Since 2013, we have returned to vacuum and aim for a significant increase in sensitivity.
Copyright/License	arXiv nonexclusive-distrib. 1.0 publication: © 2015-2025 The Author(s) (License: CC-BY-3.0)

$Exclusion regions in the $m_a$--$g_{a\gamma}$--plane achieved by CAST in the vacuum phase~\cite{Zioutas:2004hi,Andriamonje:2007ew} and with $^4$He \cite{Arik:2008mq} and $^3$He \cite{Arik:2011rx,Arik:2013nya} filling. We also show constraints from horizontal branch (HB) stars~\cite{Raffelt:2006cw,Ayala:2014pea} (a similar limit stems from blue-loop suppression in massive stars~\cite{Friedland:2012hj}), and the hot dark matter (HDM) bound~\cite{Hannestad:2005df,Hannestad:2007dd,Melchiorri:2007cd,Hannestad:2008js,Hannestad:2010yi,Archidiacono:2013cha}. The yellow band represents typical theoretical models with $\left|E/N-1.95\right|=0.07$--7. The green solid line corresponds to $E/N=0$ as in the KSVZ model \cite{Kim:1979if, Shifman:1979if}, a typical hadronic axion model. In red we show our new limits near $m_a=0.2$ and 0.4~eV from our 2012 data taking campaign with $^4$He gas.$