On the effective interactions of a light gravitino with matter fermions
On the effective interactions of a light gravitino with matter fermions
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关于光引力子与物质费米子的有效相互作用
DOI：
10.1088/1126-6708/1997/11/001
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发表时间：
1997
影响因子：
5.4
通讯作者：
F. Zwirner
中科院分区：
文献类型：
--
作者：
A. Brignole;F. Feruglio;F. Zwirner
如果引力子是轻的，而所有其他超对称粒子都是重的，我们可以考虑描述其金子成分与普通物质相互作用的有效理论。为了讨论这些相互作用的模型依赖性，我们采用自发破缺超对称性和仅两个手性超场的简单情况，与金子和无质量物质费米子相关。通过低能极限下重自旋 0 自由度的显式积分，我们推导出涉及两个物质费米子和两个金斯蒂诺的四点有效耦合。令人惊讶的是，我们的结果并不等同于通常的超对称非线性实现，即一对金斯蒂诺与物质场的能量动量张量耦合。我们通过扩大非线性实现以包括第二个独立不变耦合来解决这个难题，并且我们表明在低能展开中没有其他这种类型的独立耦合达到这个顺序。最后，我们评论了我们的结果的解释及其可能的现象学含义。
If the gravitino is light and all the other supersymmetric particles are heavy, we can consider the effective theory describing the interactions of its goldstino components with ordinary matter. To discuss the model-dependence of these interactions, we take the simple case of spontaneously broken supersymmetry and only two chiral superfields, associated with the goldstino and a massless matter fermion. We derive the four-point effective coupling involving two matter fermions and two goldstinos, by explicit integration of the heavy spin-0 degrees of freedom in the low-energy limit. Surprisingly, our result is not equivalent to the usual non-linear realization of supersymmetry, where a pair of goldstinos couples to the energy-momentum tensor of the matter fields. We solve the puzzle by enlarging the non-linear realization to include a second independent invariant coupling, and we show that there are no other independent couplings of this type up to this order in the low-energy expansion. We conclude by commenting on the interpretation of our results and on their possible phenomenological implications.