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arXiv 1504.05403hep-ph
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自然度还原

Naturalness redux

Marco Fabbrichesi, Alfredo Urbano

摘要:

自然性的概念,正如最初设想的那样,仅仅指的是引入更重的态所引起的希格斯玻色子玻色子质量的有限重整化。在这方面,当新的大质量态与希格斯场耦合时,自然性仍然是建立标准模型之外的模型的一个强有力的启发性原则。最令人信服的例子是中微子质量的产生。在本文中,我们面对这个问题,从一个新的角度。负责跷跷板机制的右手扇区--在电弱标度以上引入了一个大的能量阈值--被制成超对称以符合自然性,而标准模型保持不变和非超对称。自然性要求所需的抵消只在两个环处发生,从而提供了将右手中微子质量尺度增加到比自然性所允许的通常值高出一个数量级的可能性。如果标准模型的弱玻色子部分也是超对称的,那么抵消在三个环处破裂,新物理学的规模可以进一步提高。在I型跷跷板中,这种实现方式提供了自然的右手中微子质量,同时大到足以引起重子生成(通过瘦生)。该模型包含了一个暗物质候选者和轻子部分独特的新物理。

英文摘要:

The idea of naturalness, as originally conceived, refers only to the finite renormalization of the Higgs boson mass induced by the introduction of heavier states. In this respect, naturalness is still a powerful heuristic principle in model building beyond the standard model whenever new massive states are coupled to the Higgs field. The most compelling case is provided by the generation of neutrino masses. In this paper we confront this problem from a new perspective. The right-handed sector responsible for the seesaw mechanism---which introduces a large energy threshold above the electroweak scale---is made supersymmetric to comply with naturalness while the standard model is left unchanged and non-supersymmetric. Cancellations necessary to the naturalness requirement break down only at two loops, thus offering the possibility to increase the right-handed neutrino mass scale up to one order of magnitude above the usual values allowed by naturalness. If also the weak boson sector of the standard model is made supersymmetric, cancellations break down at three loops and the scale of new physics can be further raised. In the type-I seesaw, this implementation provides right-handed neutrino masses that are natural and at the same time large enough to give rise to baryogenesis (via leptogenesis). The model contains a dark matter candidate and distinctive new physics in the leptonic sector.

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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