This result could change physics forever

207 times the mass of an electron! Out of curiosity why hasn't it popped up before? With the millions of collision experiments that have gone on, it has somehow remained invisible to us? Has there been some breakthrough we have made that's enabled us to see it, or have we just not been monitoring for its signature or was it just so unusual that we never thought to look for it? Or was there a loose cable at Fermilab?