In isospin symmetry, the different types—"flavors"—of quarks, such as an up quark or a down quark, will fragment into new particles in a symmetric way.

Neutrons and protons have equal but opposite isospin, a quantum number that describes how many up and down quarks make ... QCD calculations are called quark propagators, which encode the ...

The up quark is a mere 0.2 percent the mass of the proton, while its partner the down quark is only around 0.5 percent of the proton mass.

not yet joined up into hadrons such as protons, neutrons and mesons. This state, called a quark-gluon plasma, existed ... In collisions of argon and scandium atomic nuclei, scientists from the ...