A NEW subatomic particle called an exotic meson may have popped into
existence at the Brookhaven National Laboratory in Upton, New York. The
discovery could help to verify the 鈥渟tandard model鈥� of physics, which predicted
decades ago that the particle should exist.
Normal mesons are made up of a quark and an antiquark. But the new one is of
a type never seen before. It is either a combination of a quark, an antiquark
and a gluon, or a cluster of two quarks and two antiquarks.
A team of physicists discovered the new particle by firing normal mesons at a
hydrogen target. Exotic mesons turned up among the debris of the collisions,
they say in last week鈥檚 Physical Review Letters (vol 79, p 1630).
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鈥淭he search for exotic mesons has been going on for more than 20 years,鈥� says
Neal Cason of the University of Notre Dame in Indiana, one of the team. 鈥淭hey鈥檝e
been very elusive.鈥�