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arXiv 2201.08059hep-ph
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用协变夸克-双夸克方法计算$Δ$共振的电磁和引力形状因子

Electromagnetic and gravitational form factors of $Δ$ resonance in a covariant quark-diquark approach

Dongyan Fu, Bao-Dong Sun, Yubing Dong

摘要:

本文利用相对论协变夸克-双夸克方法同时计算了自旋$3/2$粒子的电磁和引力形状因子,即$Δ$共振.这两种形状因子分别从系统的电磁流矩阵元和能量动量张量矩阵元中提取。数值计算结果表明,该方法可以很好地再现电磁偶极子,偶极,四极和八极形状因子相比,晶格计算。我们得到的电磁矩也与其他一些方法相当。此外,所获得的引力形状因子,它给出了系统的力学性质,如质量和自旋分布,也显示为$Δ$等压线。此外,还特别讨论了D项的符号和解释。

英文摘要:

In this work, the electromagnetic and gravitational form factors of a spin-$3/2$ particle, $Δ$ resonance, are simultaneously calculated with the help of a relativistic covariant quark-diquark approach. The two kinds of form factors are separately extracted from the matrix elements of the electromagnetic current and of the energy-momentum tensor of the system. Our numerical results show that the approach can well reproduce the electromagnetic monopole, dipole, quadrupole, and octupole form factors comparing to the Lattice calculations. Our obtained electromagnetic moments are also comparable with some other approaches. Moreover, the obtained gravitational form factors, which give the mechanical properties of the system like the mass and spin distributions, are also displayed for the $Δ$ isobar. In addition, some discussions of the sign and the interpretation of the D-term are particularly given.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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