Flashes of Hidden Worlds at Colliders
  (This is a general physics level overview article about hidden sectors, and
how they motivate searches for long-lived particles. Intended for publication
in Physics Today.)
  Searches for new physics at the Large Hadron Collider have so far come up
empty, but we just might not be looking in the right place. Spectacular bursts
of particles appearing seemingly out of nowhere could shed light on some of
nature's most profound mysteries.
