论文标题
使用laplacian模式投影的核子的磁极化性
Magnetic polarisability of the nucleon using a Laplacian mode projection
论文作者
论文摘要
使用量规高斯涂抹的常规强子插值场无效地在均匀的背景磁场中隔离基态核子。有证据表明，即使存在QCD相互作用，残留的Landau模式物理学仍然处于夸克水平。在这项工作中，夸克级投影操作员是由二维晶格拉普拉斯运算符的$ su（3）\ times u（1）$ eigenmodes构建的。这些夸克级模式由周期性的有限晶格形成，其中背景场和强相互作用都存在。使用这些本征码，夸克 - 刺激器投影算子提供了计算磁场中核子能量转移所必需的增强的HADRONIC能量元素态分离。质子和中子的磁性极化性是在PACS-CS协作提供的$ 32^3 \ times 64 $动力学QCD晶格上使用此方法计算的。 A chiral effective-field theory analysis is used to connect the lattice QCD results to the physical regime, obtaining magnetic polarisabilities of $β^p = 2.79(22)({}^{+13}_{-18}) \times 10^{-4}$ fm$^3$ and $β^n = 2.06（26）（{}^{+15} _ { - 20}）\ times 10^{ - 4} $ fm $^3 $，paranthess中的数字描述了统计和系统的不确定性。
Conventional hadron interpolating fields, which utilise gauge-covariant Gaussian smearing, are ineffective in isolating ground state nucleons in a uniform background magnetic field. There is evidence that residual Landau mode physics remains at the quark level, even when QCD interactions are present. In this work, quark-level projection operators are constructed from the $SU(3) \times U(1)$ eigenmodes of the two-dimensional lattice Laplacian operator associated with Landau modes. These quark-level modes are formed from a periodic finite lattice where both the background field and strong interactions are present. Using these eigenmodes, quark-propagator projection operators provides the enhanced hadronic energy-eigenstate isolation necessary for calculation of nucleon energy shifts in a magnetic field. The magnetic polarisability of both the proton and neutron is calculated using this method on the $32^3 \times 64$ dynamical QCD lattices provided by the PACS-CS Collaboration. A chiral effective-field theory analysis is used to connect the lattice QCD results to the physical regime, obtaining magnetic polarisabilities of $β^p = 2.79(22)({}^{+13}_{-18}) \times 10^{-4}$ fm$^3$ and $β^n = 2.06(26)({}^{+15}_{-20}) \times 10^{-4}$ fm$^3$, where the numbers in parantheses describe statistical and systematic uncertainties.
