Can one particle explain both dark matter and the mysterious origins of matter and antimatter? Some physicists think so. They're calling the as-yet-only-theoretical object the "X particle." Physicists ...

Physicists at the world's largest atom smasher have detected a mysterious, primordial particle from the dawn of time. About 100 of the short-lived "X" particles — so named because of their unknown ...

In the first millionths of a second after the Big Bang, the universe was a roiling, trillion-degree plasma of quarks and gluons — elementary particles that briefly glommed together in countless ...