No. 36: Nov-Dec 1984
It should have been a Higgs particle but it wasn't -- at least not quite. So they called it a "zeta." About eight times the mass of a proton, the zeta particle was created when electrons and positrons collided at about 10 Gev (gigavolts of energy), where it appeared among the decay products of the upsilon particle. Physicists needed a Higgs particle to bolster the latest theory of particles. Unfortunately, the zeta's properties don't quite match those predicted for the Higgs particle. There are similarities, but at the moment the zeta is definitely anomalous. It turns out that there is a similar anomalous particle produced by the decay of psi particles, so the zeta is not alone.
(Thomsen, Dietrick E.; "Zeta Particle: Physicists' New Mystery," Science News, 126:84, 1984.)
Comment. It is easy to become jaded by all the confusing particles flying around physics labs these days. But we must appreciate that physicists absolutely must find that Higgs particle. Theory says that if the Higgs doesn't exist, all other particles will have either zero or infinite masses, neither of which makes much sense. Such is the power of theoretical expectations.