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

TL;DR

This paper investigates moduli as dark matter candidates predicted by string theory and supersymmetry, using Suzaku X-ray telescope data from dwarf galaxies to search for decay lines and constrain new physics.

Contribution

It presents the first deep X-ray observational search for moduli dark matter decay lines in dwarf spheroidal galaxies, setting new constraints on their properties.

Findings

No positive detection of decay lines was made.

New upper limits on moduli decay line fluxes were established.

Constraints on moduli mass and coupling parameters were improved.

Abstract

Light scalar fields called moduli arise from a variety of different models involving supersymmetry and/or string theory; thus their existence is a generic prediction of leading theories for physics beyond the standard model. They also present a formidable, long-standing problem for cosmology. We argue that an anthropic solution to the moduli problem exists in the case of small moduli masses, 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 the moduli mass of about a keV. This form of dark matter is consistent with the observed properties of structure formation, and it is amenable to detection with the help of X-ray telescopes. We present the results of a search for such dark matter particles using spectra extracted from the first deep X-ray observations of the Draco and Ursa Minor dwarf spheroidal galaxies, which are dark matter dominated systems with extreme mass-to-light ratios and low intrinsic backgrounds. No emission line is positively detected, and we set new constraints on the relevant new physics.