The leading candidates for dark matter are different classes of hypothetical particles. (sciencedaily.com)
The existence of hypothetical particles called magnetic monopoles would explain why electric charge comes in integer multiples of the charge of an electron instead of a continuous range of values, Emily Conover reported in «Magnets with a single pole are still giving physicists the slip» (SN: 2/3/18, p. 10). (sciencenews.org)
The main contender for the substance is a type of hypothetical particle known as a «weakly interacting massive particle» (WIMP). (businessinsider.com)