This find finally solves a nearly 10-year-old mystery.
Earlier experiments thought they had seen this particle but got its mass wrong—now CERN's measurement lines up with what physicists expected and is consistent with theoretical expectations based on its 2017 partner.
The detection was rock-solid too: scientists observed about 915 decay events, and it was reported with a statistical significance of 7s (seven sigma).

The detector upgrade that made this possible was led by researchers from Manchester, showing off the U.K.'s ongoing impact in global physics projects.
More than 1,000 scientists from 20 countries teamed up for this breakthrough, proof that science is definitely an international team sport.