A particle with five quarks, instead of the usual three (or one
quark and one antiquark), has been discovered. Details are at
BBC
News. The implications: new physics. The Standard Model
of Particle Physics that has been in place for about 35 years
needs serious revision, and quarks were only supposed to collect
in colour neutral, antisymmetric states, of which this is not.
New particle IS color neutral and asymmetric
This 5-quark particle does not violate existing particle physics models, but it still called “exotic” because quarks seem to really prefer to group in pairs or threes. The real mystery is why 4 quark (2 quark/2 anti-quark) and 5 quark (4 quark/1 anti-quark) objects have been so hard to find.
Re: New particle IS color neutral and asymmetric
I guess I should have paid more attention to the article myself. The
person who pointed it out to me told me that all five were matter quarks.
This seems more like a meson/baryon bound state, which is still cool.