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arXiv 1303.4573hep-ph
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具有重中间费米子的最小树能级跷跷板

Minimal Tree-Level Seesaws with a Heavy Intermediate Fermion

Kristian L. McDonald

摘要:

存在一个通用的最小树级图,有两个外部标量和一个重的中间费米子,可以通过跷跷板产生自然小的中微子质量。这张图在内部费米子线上有一个质量插入,这组图可以根据质量插入是马约拉纳型还是狄拉克型来划分。我们表明,一旦受到自然性的要求(即排除小标量真空期望值,需要微调),这组是有限的,并包含一个相对较少的元素。一些相应的模型已经出现在文献中。我们提出了剩余的原始模型,从而推广了I型和III型跷跷板,并显然耗尽了它们的最小非调优变体的列表。

英文摘要:

There exists a generic minimal tree-level diagram, with two external scalars and a heavy intermediate fermion, that can generate naturally small neutrino masses via a seesaw. This diagram has a mass insertion on the internal fermion line, and the set of such diagrams can be partitioned according to whether the mass insertion is of the Majorana or Dirac type. We show that, once subjected to the demands of naturalness (i.e. precluding small scalar vacuum expectation values that require fine-tuning), this set is finite, and contains a relatively small number of elements. Some of the corresponding models have appeared in the literature. We present the remaining original models, thus generalizing the Type-I and Type-III seesaws, and apparently exhausting the list of their minimal non-tuned variants.

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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