arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2008.00974nucl-thhep-ph
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手征有效场论中的核电流

Nuclear Currents in Chiral Effective Field Theory

Hermann Krebs

摘要:

本文综述了手征有效场论中核流计算的现状。在正式讨论了么正变换技术及其在核流中的应用之后,我们将给出矢量流、轴矢量流的所有可用表达式。矢量和轴向矢量电流将讨论到$Q$阶,前导阶贡献从$Q^{-3}$阶开始。赝标量和标量电流将讨论到$Q^0$阶,前导阶贡献从$Q^{-4}$阶开始。这是核标量、赝标量、矢量和轴矢量电流算符的次-首序(N $^3$ LO)分析的一套完整表达式。通过传输矩阵求逆和酉变换技术计算的矢量和轴向矢量电流之间的差异进行了讨论。一致的正则化的重要性是一个额外的点,这是强调:缺乏一致的正则化的轴向矢量电流运营商被证明是导致违反手征对称性的手征极限在顺序$Q$。由于这个原因,在各种出版物中讨论的$Q$阶的混合方法是不适用的。为了尊重手征对称性,在核力和电流算符的构造中需要使用相同的正则化过程。虽然一致正则化的电流算子的完整表达式还没有得到,但直到$Q$阶的电磁荷算子的等腰部分具有非常简单的形式,并且可以容易地以一致的方式正则化。作为应用,我们回顾了我们最近的高精度计算的氘核电荷形状因子与量化的误差估计。

英文摘要:

In this article, we review the status of the calculation of nuclear currents within chiral effective field theory. After formal discussion of the unitary transformation technique and its application to nuclear currents we will give all available expressions for vector, axial-vector currents. Vector and axial-vector currents will be discussed up to order $Q$ with leading-order contribution starting at order $Q^{-3}$. Pseudoscalar and scalar currents will be discussed up to order $Q^0$ with leading-order contribution starting at order $Q^{-4}$. This is a complete set of expressions in next-to-next-to-next-to-leading-order (N$^3$LO) analysis for nuclear scalar, pseudoscalar, vector and axial-vector current operators. Differences between vector and axial-vector currents calculated via transfer-matrix inversion and unitary transformation techniques are discussed. The importance of consistent regularization is an additional point which is emphasized: lack of consistent regularization of axial-vector current operators is shown to lead to a violation of the chiral symmetry in the chiral limit at order $Q$. For this reason, a hybrid approach at order $Q$, discussed in various publications, is non-applicable. To respect the chiral symmetry the same regularization procedure needs to be used in the construction of nuclear forces and current operators. Although full expressions of consistently regularized current operators are not yet available an isoscalar part of the electromagnetic charge operator up to order $Q$ has a very simple form and can be easily regularized in a consistent way. As an application, we review our recent high accuracy calculation of the deuteron charge form factor with a quantified error estimate.

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