# Which quarks can form vacuum condensates?

I faintly remember the rule of thumb that only the up, down and strange quarks can form condensates because their mass is below the QCD scale $$\Lambda_\text{QCD}$$. But why is that? Where‘s the connection between condensates and the QCD scale?

• Free theories don’t tend to condense. Unless I am mistaken, for processes which appreciably involve the heavy quarks (above the QCD scale) the theory is asymptotically free/weakly coupled. – hulsey May 18 at 8:26