Unified Interacting Quark Matter and its Astrophysical Implications. (arXiv:2009.07182v1 [astro-ph.HE])

<a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_C/0/1/0/all/0/1">Chen Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mann_R/0/1/0/all/0/1">Robert B. Mann</a>

We investigate interacting quark matter (IQM), including the perturbative QCD

correction and color superconductivity, for both up-down quark matter ($ud$QM)

and strange quark matter (SQM). We first derive an equation of state (EOS)

unifying all cases by a simple reparametrization and rescaling, through which

we manage to maximally reduce the number of degrees of freedom. We find, in

contrast to the conventional EOS $p=1/3(rho-4B_{rm eff})$ for non-interacting

quark matter, that taking the extreme strongly interacting limit on the unified

IQM EOS gives $p=rho-2B_{rm eff}$, where $B_{rm eff}$ is the effective bag

constant. We employ the unified EOS to explore the properties of pure

interacting quark stars (IQSs) composed of IQM. We describe how recent

astrophysical observations, such as the pulsar-mass measurements, the NICER

analysis, and the binary merger gravitational-wave events GW170817, GW190425,

and GW190814, further constrain the parameter space. An upper bound for the

maximum allowed mass of IQSs is found to be $M_{rm TOV}lesssim 3.23

M_{odot}$. Our analysis indicates a new possibility that the currently

observed compact stars, including the recently reported GW190814’s secondary

component ($M=2.59^{+0.08}_{-0.09}, M_{odot}$), can be quark stars composed

of interacting up-down quark matter.

We investigate interacting quark matter (IQM), including the perturbative QCD

correction and color superconductivity, for both up-down quark matter ($ud$QM)

and strange quark matter (SQM). We first derive an equation of state (EOS)

unifying all cases by a simple reparametrization and rescaling, through which

we manage to maximally reduce the number of degrees of freedom. We find, in

contrast to the conventional EOS $p=1/3(rho-4B_{rm eff})$ for non-interacting

quark matter, that taking the extreme strongly interacting limit on the unified

IQM EOS gives $p=rho-2B_{rm eff}$, where $B_{rm eff}$ is the effective bag

constant. We employ the unified EOS to explore the properties of pure

interacting quark stars (IQSs) composed of IQM. We describe how recent

astrophysical observations, such as the pulsar-mass measurements, the NICER

analysis, and the binary merger gravitational-wave events GW170817, GW190425,

and GW190814, further constrain the parameter space. An upper bound for the

maximum allowed mass of IQSs is found to be $M_{rm TOV}lesssim 3.23

M_{odot}$. Our analysis indicates a new possibility that the currently

observed compact stars, including the recently reported GW190814’s secondary

component ($M=2.59^{+0.08}_{-0.09}, M_{odot}$), can be quark stars composed

of interacting up-down quark matter.

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