Strangeon and Strangeon Star

5th Compact Stars in the QCD Phase Diagram

Lai, Xiaoyu^1 ; Xu, Renxin^2,3

School of Physics and Engineering, Hubei University of Education, Wuhan

430205, China^1

School of Physics, Peking University, Beijing

100871, China^2

Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing

100871, China^3

关键词: Compact objects;    Compact stars;    Flavor symmetry;    Low-energy;    Quantum chromo dynamics;    Quark matter;    Strong interaction;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/861/1/012027/pdf
DOI  :  10.1088/1742-6596/861/1/012027

来源: IOP

【 摘 要 】

The nature of pulsar-like compact stars is essentially a central question of the fundamental strong interaction (explained in quantum chromo-dynamics) at low energy scale, the solution of which still remains a challenge though tremendous efforts have been tried. This kind of compact objects could actually be strange quark stars if strange quark matter in bulk may constitute the true ground state of the strong-interaction matter rather than56Fe (the so-called Witten's conjecture). From astrophysical points of view, however, it is proposed that strange cluster matter could be absolutely stable and thus those compact stars could be strange cluster stars in fact. This proposal could be regarded as a general Witten's conjecture: strange matter in bulk could be absolutely stable, in which quarks are either free (for strange quark matter) or localized (for strange cluster matter). Strange cluster with three-light-flavor symmetry is renamed strangeon, being coined by combining "strange nucleon" for the sake of simplicity. A strangeon star can then be thought as a 3-flavored gigantic nucleus, and strangeons are its constituent as an analogy of nucleons which are the constituent of a normal (micro) nucleus. The observational consequences of strangeon stars show that different manifestations of pulsarlike compact stars could be understood in the regime of strangeon stars, and we are expecting more evidence for strangeon star by advanced facilities (e.g., FAST, SKA, and eXTP).