Broken SU(6) symmetry and massive hybrid stars

Abstract In this work we revisit the quantum hadrodynamics (QHD) formalism to investigate hyperonic and hybrid stars with hyperon-meson couplings fixed via broken SU(6) group, in favor of a more general flavor group SU(3). We also employ an additional channel, the strangeness-hidden ϕ meson, which couples only to the hyperons. In hybrid stars, the quark phase is built with the SU(3) NJL model also with an additional vector channel in the Lagrangian. We found that within the models chosen the hyperon onset cannot be avoided by the quark-hadron phase transition, once the hyperon threshold always happens at lower density. Also, the contribution of the quark core in a hybrid star is more relevant to the radius than to the mass, and strongly depends on the quark equation of state. We are able to reproduce 2.21 M ⊙ hyperonic star and 2.10 M ⊙ hybrid star. Both results are in agreement with the recently detected hyper massive pulsar MSP J0740+6620.