A N on-therm alW IM P 'M iracle'

Lightscalareldswith only gravitationalstrength couplingsaretypically presentin UV com plete theoriesofphysicsbeyond the Standard M odel. In the early universe itisnaturalfortheseelds to dom inate theenergy density,and theirsubsequentdecay { ifpriorto BBN { willtypically yield som e dark m atterparticlesin theirdecay products. In thispaperwe m ake the observation thata Non-therm alW IM P 'M iracle'm ayresult:thatis,in thesim plestsolution tothecosm ologicalm oduli problem ,non-therm ally produced W IM Pscan naturally accountfortheobserved dark m atterrelic density.Such a solution m ay begeneric in string theory com pactications. PACS num bers: I. IN T R O D U C T IO N