(a) Darkon-Higgs coupling as a function of darkon mass for Higgs mass values GeV in SM4+D. (b) The corresponding darkon-nucleon cross-section , compared to 90%-CL upper limits from CDMS (brown long-dashed curves) [114, 115], XENON10 (green dot-dashed curve) [116], and XENON100 (black short-dashed curve) [110], as well as a (gray) patch compatible with the DAMA modulation signal at the 5 level [117], the 90%-CL (magenta) signal region suggested by CoGeNT [31], and two -confidence (cyan) areas representing the CRESST-II result [118]. Also plotted is the projected sensitivity of XENON1T (blue dotted curve) [119]. The black-dotted parts of the curves in (a) are ruled out by the direct search limits in (b) as discussed in the text.
