Bayesian inference of dense matter EOS encapsulating a first-order hadron-quark phase transition from observables of canonical neutron stars. (arXiv:2009.13653v2 [nucl-th] UPDATED)
<a href="http://arxiv.org/find/nucl-th/1/au:+Xie_W/0/1/0/all/0/1">Wen-Jie Xie</a>, <a href="http://arxiv.org/find/nucl-th/1/au:+Li_B/0/1/0/all/0/1">Bao-An Li</a>
[Purpose:] We infer the posterior probability distribution functions (PDFs)
and correlations of nine parameters characterizing the EOS of dense
neutron-rich matter encapsulating a first-order hadron-quark phase transition
from the radius data of canonical NSs reported by LIGO/VIRGO, NICER and Chandra
Collaborations. We also infer the quark matter (QM) mass fraction and its
radius in a 1.4 M$_{odot}$ NS and predict their values in more massive NSs.
[Method:] Meta-modelings are used to generate both hadronic and QM EOSs in the
Markov-Chain Monte Carlo sampling process within the Bayesian statistical
framework. An explicitly isospin-dependent parametric EOS for the $npemu$
matter in NSs at $beta$ equilibrium is connected through the Maxwell
construction to the QM EOS described by the constant speed of sound (CSS) model
of Alford, Han and Prakash. [Results:] (1) The most probable values of the
hadron-quark transition density $rho_t/rho_0$ and the relative energy density
jump there $Deep/ep_t$ are $rho_t/rho_0=1.6^{+1.2}_{-0.4}$ and
$Deep/ep_t=0.4^{+0.20}_{-0.15}$ at 68% confidence level, respectively. The
corresponding probability distribution of QM fraction in a 1.4 M$_{odot}$ NS
peaks around 0.9 in a 10 km sphere. Strongly correlated to the PDFs of $rho_t$
and $Deep/ep_t$, the PDF of the QM speed of sound squared $cQMsq/c^2$ peaks
at $0.95^{+0.05}_{-0.35}$, and the total probability of being less than 1/3 is
very small. (2) The correlations between PDFs of hadronic and QM EOS parameters
are very weak. [Conclusions:] The available astrophysical data considered
together with all known EOS constraints from theories and terrestrial nuclear
experiments prefer the formation of a large volume of QM even in canonical NSs.
[Purpose:] We infer the posterior probability distribution functions (PDFs)
and correlations of nine parameters characterizing the EOS of dense
neutron-rich matter encapsulating a first-order hadron-quark phase transition
from the radius data of canonical NSs reported by LIGO/VIRGO, NICER and Chandra
Collaborations. We also infer the quark matter (QM) mass fraction and its
radius in a 1.4 M$_{odot}$ NS and predict their values in more massive NSs.
[Method:] Meta-modelings are used to generate both hadronic and QM EOSs in the
Markov-Chain Monte Carlo sampling process within the Bayesian statistical
framework. An explicitly isospin-dependent parametric EOS for the $npemu$
matter in NSs at $beta$ equilibrium is connected through the Maxwell
construction to the QM EOS described by the constant speed of sound (CSS) model
of Alford, Han and Prakash. [Results:] (1) The most probable values of the
hadron-quark transition density $rho_t/rho_0$ and the relative energy density
jump there $Deep/ep_t$ are $rho_t/rho_0=1.6^{+1.2}_{-0.4}$ and
$Deep/ep_t=0.4^{+0.20}_{-0.15}$ at 68% confidence level, respectively. The
corresponding probability distribution of QM fraction in a 1.4 M$_{odot}$ NS
peaks around 0.9 in a 10 km sphere. Strongly correlated to the PDFs of $rho_t$
and $Deep/ep_t$, the PDF of the QM speed of sound squared $cQMsq/c^2$ peaks
at $0.95^{+0.05}_{-0.35}$, and the total probability of being less than 1/3 is
very small. (2) The correlations between PDFs of hadronic and QM EOS parameters
are very weak. [Conclusions:] The available astrophysical data considered
together with all known EOS constraints from theories and terrestrial nuclear
experiments prefer the formation of a large volume of QM even in canonical NSs.
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