论文标题
晶格QCD的核子电荷半径的模型非依赖性测定
Model-independent determination of the nucleon charge radius from lattice QCD
论文作者
论文摘要
核子形式因子的晶格QCD计算仅限于Euclidean四摩Momentum转移的离散值。因此，半径的提取通常依赖于参数化和拟合晶格QCD数据，以使其斜率接近零动量转移。我们研究了一种新方法，该方法允许直接从现有的晶格QCD数据中计算核子半径，而无需假设对基础外形的动量依赖性的功能形式。该方法用于核子$ \ langle r^2_ \ Mathrm {isov} \ rangle $的均方根电荷半径，以及对$ \ langle r^2_p \ rangle $和$ \ langle rangle r^2_n \ rangle r^2_n \ rangle $ proton和proton的Quark连接的贡献。使用$ n_f = 2+1+1 $最大扭曲的质量三叶草改良的费米子在物理夸克质量和$ a = 0.08 \ mathrm {fm {fm} $的晶格间距上进行计算。
Lattice QCD calculations of nucleon form factors are restricted to discrete values of the Euclidean four-momentum transfer. Therefore, the extraction of radii typically relies on parametrizing and fitting the lattice QCD data to obtain its slope close to zero momentum transfer. We investigate a new method, which allows to compute the nucleon radius directly from existing lattice QCD data, without assuming a functional form for the momentum dependence of the underlying form factor. The method is illustrated for the case of the isovector mean square charge radius of the nucleon $\langle r^2_\mathrm{isov} \rangle$ and the quark-connected contributions to $\langle r^2_p\rangle$ and $\langle r^2_n \rangle$ for the proton and neutron, respectively. Computations are performed using a single gauge ensemble with $N_f=2+1+1$ maximally twisted mass clover-improved fermions at physical quark mass and a lattice spacing of $a=0.08\mathrm{fm}$.
