Department of Physics, University of Toronto, Toronto, Ontario M5S1A7, Canada.
Phys Rev Lett. 2018 Jun 1;120(22):222001. doi: 10.1103/PhysRevLett.120.222001.
If quark matter is energetically favored over nuclear matter at zero temperature and pressure, then it has long been expected to take the form of strange quark matter (SQM), with comparable amounts of u, d, and s quarks. The possibility of quark matter with only u and d quarks (udQM) is usually dismissed because of the observed stability of ordinary nuclei. However, we find that udQM generally has lower bulk energy per baryon than normal nuclei and SQM. This emerges in a phenomenological model that describes the spectra of the lightest pseudoscalar and scalar meson nonets. Taking into account the finite size effects, udQM can be the ground state of baryonic matter only for baryon number A>A_{min} with A_{min}≳300. This ensures the stability of ordinary nuclei and points to a new form of stable matter just beyond the periodic table.
如果在零温度和零压力下夸克物质比核物质更具能量优势，那么人们早就期望它呈现出奇异夸克物质（SQM）的形式，其中包含数量相当的 u、d 和 s 夸克。由于普通原子核的稳定性，通常会排除只含有 u 和 d 夸克的夸克物质（udQM）的可能性。然而，我们发现 udQM 的每核子体能量通常低于普通原子核和 SQM。这在描述最轻赝标量和标量介子八重态能谱的唯象模型中出现。考虑到有限尺寸效应，只有对于重子数 A>A_{min}（其中 A_{min}≳300），udQM 才能成为重子物质的基态。这确保了普通原子核的稳定性，并指向了元素周期表之外的一种新的稳定物质形式。
