the pressure from the electrons. The constant B is so determined that the pressure vanishes at zero density and temperature. In addition to the Eqs. (3) and (4), the pressure must satisfy, so that local electric and colour charge neutrality conditions are met. Once, the pressure as a function of quark chemical potential is known, quark matter EOS can be easily computed. The model parameters, the current quark masses m$_{u}$$_{,}$$_{d}$$_{,}$$_{s}$ , quark-antiquark coupling G$_{S}$ , the strength K of the six fermion or ”t Hooft” interaction and the cuto ff parameter Λ are taken to be [41], After fixing the masses of the up and down quarks, m$_{u}$ = m$_{d}$ = 5 . 5 MeV, the other four parameters are chosen to reproduce the following observables of vacuum QCD [41]: m$_{π}$ = 135 . 0 MeV, m$_{K}$ = 497 . 7 MeV, m$_{η}$ ′ = 957 . 8 MeV, and f$_{π}$ = 92 . 4 MeV. This parameter set gives m$_{η}$ = 514 . 8 MeV. The value of B for this set of parameters is (425 . 4MeV)$^{4}$. There are two more parameters, the diquark coupling strength G$_{D}$ and the vector current coupling strength G$_{V}$ , which are not known. One expects that the diquark coupling has a similar strength as the quark-antiquark coupling. We construct quark matter EOS for G$_{D}$ = 1 . 1 − 1 . 2 G$_{S}$ with G$_{V}$ = 0 − 0 . 2 G$_{S}$ . In the 2SC phase, pairing occurs only between the u and d quarks and the s quarks remain unpaired leading to Δ$_{1}$ = Δ$_{2}$ = 0 and Δ$_{3}$ GLYPH<nequal> 0. On the other hand, in the CFL phase, Δ$_{1}$ GLYPH<nequal> 0, Δ$_{2}$ GLYPH<nequal> 0 and Δ$_{3}$ GLYPH<nequal> 0. In the left panels of Figs. 2 and 3, we plot the pressure as a function of the quark chemical potential for the nuclear matter and for the quark matter in the 2SC and CFL phases. The phase realized at a given chemical potential is the one having largest pressure. Thus, it is evident from the P − µ curves that direct transition from nuclear matter to the CFL quark matter occurs 5 n$_{Q}$ ≡ ∂ p ∂µ$_{Q}$ = 0 , (5) n$_{3}$ ≡ ∂ p ∂µ$_{3}$ = 0 , (6) n$_{8}$ ≡ ∂ p ∂µ$_{8}$ = 0 , (7) m$_{u}$ = m$_{d}$ = 5 . 5 MeV , (8) m$_{s}$ = 140 . 7 MeV , (9) G$_{S}$ Λ 2 = 1 . 835 , (10) K Λ 5 = 12 . 36 , (11) Λ = 602 . 3 MeV. (12)