Diquark Bose-Einstein condensation at strong coupling

We investigate the phase structure of the $S{U}_f(2)\otimes S{U}_c(3)$ Nambu–Jona-Lasinio model as a function of the scalar diquark coupling strength. Above a critical coupling, the binding energy is sufficiently large to overcompensate the quark masses and a massless scalar diquark bound state emerges which leads to Bose condensation already in the vacuum.