Moduli dark matter and the search for its decay line using Suzaku X-ray telescope

摘要

Light scalar fields called moduli arise from a variety of different modelsinvolving supersymmetry and/or string theory; thus their existence is a genericprediction of leading theories for physics beyond the standard model. They alsopresent a formidable, long-standing problem for cosmology. We argue that ananthropic solution to the moduli problem exists in the case of small modulimasses, and that it automatically leads to dark matter in the form of moduli.The recent discovery of the 125 GeV Higgs boson implies a lower bound on themoduli mass of about a keV. This form of dark matter is consistent with theobserved properties of structure formation, and it is amenable to detectionwith the help of X-ray telescopes. We present the results of a search for suchdark matter particles using spectra extracted from the first deep X-rayobservations of the Draco and Ursa Minor dwarf spheroidal galaxies, which aredark matter dominated systems with extreme mass-to-light ratios and lowintrinsic backgrounds. No emission line is positively detected, and we set newconstraints on the relevant new physics.