Answer
No, it is impossible to find particles made up of 2 quarks and no antiquarks.
Yes, it would be possible for a particle to be made of 2 quarks and 2 antiquarks, using the ideas of QCD.
Work Step by Step
No, it is impossible to find particles made up of 2 quarks and no antiquarks. As stated on page 936, using the ideas of quantum chromodynamics (QCD), baryons and mesons are colorless/white. There are 3 types of “color charge”, so a particle containing only two quarks would have a particular color, and not be colorless. It is required to have three quarks (of three different colors) or a quark–antiquark pair for a particle to be colorless/white.
Yes, it would be possible for a particle to be made of 2 quarks and 2 antiquarks, using the ideas of QCD. The colors could cancel, and the resulting particle could be white or colorless. Such a particle, the $Z_C(3900)$, was discovered in 2013.
