Dogus University, Istanbul, Turkey.
Phys Rev Lett. 2011 Dec 23;107(26):261302. doi: 10.1103/PhysRevLett.107.261302.
The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using (3)He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with (4)He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV≲m(a)≲0.64 eV. 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 g(aγ)≲2.3×10(-10) GeV(-1) at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m(a)≲1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.
欧洲核子研究中心（CERN）太阳轴子望远镜（CAST）利用（3）He 作为缓冲气体，将太阳轴子的搜索范围扩大。在 T=1.8 K 时，与我们之前使用（4）He 的测量相比，这允许设置更大的压力，从而对更高质量的轴子更敏感。在 252 个不同压力设置中的每一个设置上，我们进行了大约 1 小时的数据采集，扫描了 0.39 eV≲m(a)≲0.64 eV 的轴子质量范围。由于当磁铁指向太阳时没有多余的 X 射线，我们在 95%置信水平下对轴子-光子耦合设定了一个典型的上限 g(aγ)≲2.3×10(-10) GeV(-1)，具体值取决于压力设置。在我们的质量范围内，Kim-Shifman-Vainshtein-Zakharov 轴子被排除在上限之外，这是首次对任何太阳轴子搜索进行排除。未来，我们将把搜索范围扩大到 m(a)≲1.15 eV，与宇宙热暗物质边界舒适地重叠。
