http://www.nature.com/news/quark-quartet-opens-fresh-vista-on-matter-1.13225
Physicists have resurrected a particle that may have existed in the first hot moments after the Big Bang. Arcanely called Zc(3900), it is the first confirmed particle made of four quarks, the building blocks of much of the Universe’s matter.
Until now, observed particles made of quarks have contained only three quarks (such as protons and neutrons) or two quarks (such as the pions and kaons found in cosmic rays). Although no law of physics precludes larger congregations, finding a quartet expands the ways in which quarks can be snapped together to make exotic forms of matter.
http://www.nature.com/news/2011/110723/full/news.2011.436.html
Asymmetric quarks defy standard model of physics
Newly released observations of the top quark — the heaviest of all known fundamental particles — could topple the standard model of particle physics. Data from collisions at the Tevatron particle accelerator at Fermilab in Batavia, Illinois, hint that some of the top quark’s interactions are governed by an as-yet unknown force, communicated by a hypothetical particle called the top gluon. The standard model does not allow for such a force or particle.
http://www.nature.com/news/2009/090401/full/458559a.html
Quark statistics shed light on Universe’s symmetry
The fundamental asymmetry in the laws of physics called charge–parity (CP) violation is tiny, yet it looms large enough in physics to have led to Nobel prizes on three occasions. A persistent puzzle is why the asymmetry is so small — some theories imply that it could, and perhaps should, be much bigger. Now, research1, 2 is bolstering a previous suggestion that the smallness is not a mystery, but rather an inevitable consequence of another basic fact in physics: that the three known families of quarks have the masses that they do.
http://www.nature.com/news/2007/071130/full/news.2007.292.html
Splitting the quark
Are there pea-sized objects as heavy as the Moon out there in space? Perhaps so, if quarks, the constituent particles of atoms, are themselves made up of still smaller particles.
Fredrik Sandin and Johan Hansson of Luleå University of Technology in Sweden say that these hypothetical particles, called preons, might exist in super-dense chunks left over from the beginning of the Universe. Their work predicts that these heavy objects should be detectable with current astronomical techniques1. This helps to turn a highly speculative hypothesis into a testable idea.