511 keV gamma ray from moduli decay in the Galactic bulge

摘要

We show that the e(+) + e(-) decay of a light scalar boson of mass 1-10 MeV may account for the fluxes of 511 keV gamma ray observed by SPYINTEGRAL. We argue that candidates of such a light scalar boson is one of the string moduli or a scalar partner of the axion in a supersymmetric theory. (c) 2005 Elsevier B.V. All rights reserved.