Broken SU(6) symmetry and massive hybrid stars. (arXiv:2004.07909v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Lopes_L/0/1/0/all/0/1">Luiz L. Lopes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Menezes_D/0/1/0/all/0/1">Debora P. Menezes</a>
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 $phi$ 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 puzzle 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 relavant to the radius than to the mass, and strongly depends on the quark
equation of state. We are able to reproduce 2.21 $M_odot$ hyperonic star and
2.10 $M_odot$ hybrid star. Both results are in agreement with the recently
detected hyper massive pulsar MSP J0740+6620.
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 $phi$ 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 puzzle 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 relavant to the radius than to the mass, and strongly depends on the quark
equation of state. We are able to reproduce 2.21 $M_odot$ hyperonic star and
2.10 $M_odot$ hybrid star. Both results are in agreement with the recently
detected hyper massive pulsar MSP J0740+6620.
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