The discovery could be an important step to unifying theories about how the universe is constructed, and so how it came into existence. Though the particle has been predicted by theory since the late 1970s, it has taken years to design particle accelerators and experiments sensitive enough to detect it.
Professor Frank Close, at the UK's Rutherford Appleton Laboratory in Didcot, said: "Everything that we are made of - atoms, electron, and so on - is made of tinier particles called quarks, which are glued together in triplets. Every experiment before has been about putting energy in to excite quarks, and observing what happens. But it should also be possible, in theory, to excite the glue."
The discovery was made by physicists at the Brookhaven National Laboratory in the US. The results are published in this week's issue of Physical Review Letters. It follows a collaborative effort by teams at Brookhaven, Moscow, and various USReuse content