Excess antielectrons aren’t from nearby dead stars, study says
The finding keeps open the possibility that the particles come from dark matter
WATCHING LIKE A HAWC The HAWC experiment near Puebla, Mexico, uses more than 300 tanks of water to detect the signatures of gamma rays. Its new observations have reignited a debate about the source of unexplained antimatter particles from space.
J. Goodman
New observations of the whirling cores of dead stars have deepened the mystery behind a glut of antimatter particles raining down on Earth from space.
The particles are antielectrons, also known as positrons, and could be a sign of dark matter — the exotic and unidentified culprit that makes up the bulk of the universe’s mass. But more mundane explanations are also plausible: Positrons might be spewed from nearby pulsars, the spinning remnants of exploded stars, for example. But researchers with the High-Altitude Water Cherenkov Observatory, or HAWC, now have called the pulsar hypothesis into question in a paper published in the Nov. 17 Science.
Although the new observations don’t directly support the dark matter explanation, “if you have a few alternatives and cast doubt on one of them, then the other becomes more likely," says HAWC scientist Jordan Goodman
