Ghostly neutrinos have never been seen inside a particle accelerator, until now. Physicists have detected "ghost particles" called neutrinos inside an atom smasher for the first time. The tiny particles, known as neutrinos , were spotted during the test run of a new detector at the Large Hadron Collider (LHC) — the world's largest particle accelerator, located at CERN near Geneva, Switzerland. The landmark discovery, made by CERN's Forward Search Experiment (FASER) collaboration and presented in a Nov. 24 paper in the journal Physical Review D, is not just the first time that neutrinos have been seen inside the LHC, but it's also the first time they've been found inside any particle accelerator. The breakthrough opens up a completely new window through which scientists can investigate the subatomic world. "Prior to this project, no sign of neutrinos has ever been seen at a particle collider," study co-author Jonathan Feng, a physics professor at...