E-Mail IMAGE: Jack Manley (left) is a UD doctoral student and Swati Singh is an assistant professor in the College of Engineering's Department of Electrical and Computer Engineering. view more Credit: Photo by Evan Krape, photo composite by Jeffrey C. Chase Scientists are certain that dark matter exists. Yet, after more than 50 years of searching, they still have no direct evidence for the mysterious substance. University of Delaware's Swati Singh is among a small group of researchers across the dark matter community that have begun to wonder if they are looking for the right type of dark matter. "What if dark matter is much lighter than what traditional particle physics experiments are looking for?" said Singh, an assistant professor of electrical and computer engineering at UD.