Campos, A. H.Maia, JMFRosenfeld, R.2014-05-202014-05-202004-07-01Physical Review D. College Pk: American Physical Soc, v. 70, n. 2, 7 p., 2004.0556-2821http://hdl.handle.net/11449/23532Top-down models assume that the still unexplained ultrahigh energy cosmic rays (UHECR's) are the decay products of superheavy particles. Such particles may have been produced by one of the post-inflationary reheating mechanisms and may account for a fraction of the cold dark matter. In this paper, we assess the phenomenological applicability of the simplest instant preheating framework not to describe a reheating process, but as a mechanism to generate relic supermassive particles as possible sources of UHECR's. We use cosmic ray flux and cold dark matter observational data to constrain the parameters of the model.7engArtigo10.1103/PhysRevD.70.023003WOS:000223233400006Acesso restritoWOS000223233400006.pdf