Gravitational wave echoes from interacting quark stars. (arXiv:2107.09654v1 [hep-ph])

<a href="http://arxiv.org/find/hep-ph/1/au:+Zhang_C/0/1/0/all/0/1">Chen Zhang</a>

We show that interacting quark stars (IQSs) composed of interacting quark

matter (IQM), including the strong interaction effects such as perturbative QCD

corrections and color superconductivity, can be compact enough to feature a

photon sphere that is essential to the signature of gravitational wave echoes.

We utilize an IQM equation of state unifying all interacting phases by a simple

reparametrization and rescaling, through which we manage to maximally reduce

the number of degrees of freedom into one dimensionless parameter

$bar{lambda}$ that characterizes the relative size of strong interaction

effects. It turns out that gravitational wave echoes are possible for IQSs with

$bar{lambda}gtrsim10$ at large center pressure. Rescaling the dimension

back, we illustrate its implication on the dimensional parameter space of

effective bag constant $B_{rm eff}$ and the superconducting gap $Delta$ with

variations of the perturbative QCD parameter $a_4$ and the strange quark mass

$m_s$. We calculate the rescaled GW echo frequencies $bar{f}_text{echo}$

associated with IQSs, from which we obtain a simple scaling relation for the

minimal echo frequency $f_text{echo}^{rm min}approx 5.76 {sqrt{B_{rm

eff}/text{(100 MeV)}^4}} ,,, rm kHz$ at the large $bar{lambda}$ limit.

We show that interacting quark stars (IQSs) composed of interacting quark

matter (IQM), including the strong interaction effects such as perturbative QCD

corrections and color superconductivity, can be compact enough to feature a

photon sphere that is essential to the signature of gravitational wave echoes.

We utilize an IQM equation of state unifying all interacting phases by a simple

reparametrization and rescaling, through which we manage to maximally reduce

the number of degrees of freedom into one dimensionless parameter

$bar{lambda}$ that characterizes the relative size of strong interaction

effects. It turns out that gravitational wave echoes are possible for IQSs with

$bar{lambda}gtrsim10$ at large center pressure. Rescaling the dimension

back, we illustrate its implication on the dimensional parameter space of

effective bag constant $B_{rm eff}$ and the superconducting gap $Delta$ with

variations of the perturbative QCD parameter $a_4$ and the strange quark mass

$m_s$. We calculate the rescaled GW echo frequencies $bar{f}_text{echo}$

associated with IQSs, from which we obtain a simple scaling relation for the

minimal echo frequency $f_text{echo}^{rm min}approx 5.76 {sqrt{B_{rm

eff}/text{(100 MeV)}^4}} ,,, rm kHz$ at the large $bar{lambda}$ limit.

http://arxiv.org/icons/sfx.gif