Oops-Leon

Oops-Leon is the name given by particle physicists to what was thought to be a new subatomic particle "discovered" at Fermilab in 1976. The E288 experiment team, a group of physicists led by Leon Lederman who worked on the E288 particle detector, announced that a particle with a mass of about 6.0 GeV, which decayed into an electron and a positron, was being produced by the Fermilab particle accelerator.[1] The particle's initial name was the greek letter Upsilon (${\displaystyle \Upsilon \,}$). After taking further data, the group discovered that this particle did not actually exist, and the "discovery" was named "Oops-Leon" as a pun on the original name (mispronounced /ˈjuːpsɪlɒn/) and the first name of the E288 collaboration leader.[2]