Department of Physics, University of Washington, Box 351560, Seattle, Washington 98195, USA.
Department of Physics, University of Washington, Box 351560, Seattle, Washington 98195, USA and Institute for Nuclear Theory, Box 351550, Seattle, Washington 98195-1550, USA.
Phys Rev Lett. 2014 Dec 19;113(25):252001. doi: 10.1103/PhysRevLett.113.252001. Epub 2014 Dec 16.
We present the results of lattice QCD calculations of the magnetic moments of the lightest nuclei, the deuteron, the triton, and ^{3}He, along with those of the neutron and proton. These calculations, performed at quark masses corresponding to m_{π}∼800 MeV, reveal that the structure of these nuclei at unphysically heavy quark masses closely resembles that at the physical quark masses. In particular, we find that the magnetic moment of ^{3}He differs only slightly from that of a free neutron, as is the case in nature, indicating that the shell-model configuration of two spin-paired protons and a valence neutron captures its dominant structure. Similarly a shell-model-like moment is found for the triton, μ_{^{3}H}∼μ_{p}. The deuteron magnetic moment is found to be equal to the nucleon isoscalar moment within the uncertainties of the calculations. Furthermore, deviations from the Schmidt limits are also found to be similar to those in nature for these nuclei. These findings suggest that at least some nuclei at these unphysical quark masses are describable by a phenomenological nuclear shell model.
我们呈现了格点 QCD 计算的轻核（氘核、氚核和氦-3）、中子和质子磁矩的结果。这些在夸克质量对应于 m_{π}∼800 MeV 的计算表明，在物理夸克质量下，这些原子核的结构与在非常重的夸克质量下的结构非常相似。特别地，我们发现氦-3 的磁矩与自由中子的磁矩仅略有差异，这与自然界中的情况相同，表明由两个自旋配对的质子和一个价中子构成的壳模型构型捕获了其主要结构。类似地，对于氚核也发现了壳模型样的磁矩，μ_{^{3}H}∼μ_{p}。氘核的磁矩与计算中的不确定性内的核子同位旋磁矩相等。此外，这些核的 Schmidt 限制的偏差也与自然界中的偏差相似。这些发现表明，至少在这些非物理夸克质量下的某些核可以用唯象的核壳模型来描述。
