Stability window in the G₂−V₁ plane. The colored area under the ϵ/n_b = 930 MeV curve indicates the stability region of the strange quark matter (m_u = 2.3 MeV, m_d = 4.8 MeV, m_s = 95 MeV) at zero temperature and pressure. The solid line indicates where the energy per baryon of the quark matter matches with the energy per nucleon in the ⁵⁶Fe most bound nucleus. Considering the QCD sum rules, the estimated value of G₂ = (0.012 ± 0.006) GeV⁴ is out of the stability region.