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arXiv 1905.06299nucl-thhep-ph
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电磁自旋1电流的模型无关形状因子约束

Model-independent form-factor constraints for electromagnetic spin-1 currents

Helmut Haberzettl

摘要:

利用Ward-Takahashi恒等式形式的局部规范不变性和正确构造的电流算符必须不含运动学奇点的事实,证明了具有质量$m$和电荷$e$的基本自旋1粒子的磁矩$μ$和四极矩$Q$与$2 mμ+ m^2 Q = e$有关,从而限制了Sachs形状因子的归一化.这种关系在标准模型的树级上当然成立,但我们证明了它在一般情况下对来自基本场的自旋为1的修饰态仍然成立。给出了自旋为1的传播子和流的一般表达式,表明该结果与任何修饰效应或模型方法无关。

英文摘要:

Using local gauge invariance in the form of the Ward-Takahashi identity and the fact that properly constructed current operators must be free of kinematic singularities, it is shown that the magnetic moment $μ$ and the quadrupole moment $Q$ of an elementary spin-1 particle with mass $m$ and charge $e$ are related by $2 mμ+ m^2 Q = e$, thus constraining the normalizations of the Sachs form factors. This relation holds true as a matter of course at the tree level in the standard model, but we prove it remains true in general for dressed spin-1 states derived from elementary fields. General expressions for spin-1 propagators and currents with arbitrary hadronic dressing are given showing the result to be independent of any dressing effect or model approach.

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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