Kinetic mixing of the photon with hidden U(1)s in string phenomenology
Kinetic mixing of the photon with hidden U(1)s in string phenomenology
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DOI：
10.1088/1126-6708/2008/07/124
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发表时间：
2008-07-01
影响因子：
5.4
通讯作者：
Ringwald, A.
中科院分区：
文献类型：
--
作者：
Abel, S. A.;Goodsell, M. D.;Ringwald, A.
第二类弦理论中标准模型的嵌入通常包含从整体中的D膜产生的各种U(1)规范因子。一般说来，没有理由只有一个--对应于弱超荷的那个--应该是无质量的。观测要求标准模型粒子在附加无质量U(1)S作用下必须是中性的(或具有极小的电荷)，即后者必须属于所谓的隐扇区。然而，重信使的交换可以导致超荷和隐区U(1)S之间的动力学混合，这一点可以在不久的将来的实验中得到验证。这提供了一个对隐藏部分的强有力的探索，因此，弦理论本身也实现了。在这篇文章中，我们用各种方法展示了如何从基本的II型弦紧化中得到动力学混合，涉及D膜的超对称和非超对称构型，无论是在大体积中还是在具有通量的翘曲背景中。我们首先通过一个明确的例子证明了动力学混合发生在一个完全超对称的装置中，在这个装置中我们可以使用共形场论技术。然后，我们发展了一种超重力方法，使我们能够在更广泛的背景下研究这一现象，在那里我们发现，在通量紧凑的背景下，动力学混合是自然的。我们讨论了在低能前沿实验的现象学后果，寻找光、亚电子伏特甚至无质量隐藏扇区U(1)规范玻色子和微小粒子的信号。
Embeddings of the standard model in type II string theory typically contain a variety of U(1) gauge factors arising from D-branes in the bulk. In general, there is no reason why only one of these - the one corresponding to weak hypercharge - should be massless. Observations require that standard model particles must be neutral (or have an extremely small charge) under additional massless U(1)s, i.e. the latter have to belong to a so called hidden sector. The exchange of heavy messengers, however, can lead to a kinetic mixing between the hypercharge and the hidden-sector U(1)s, that is testable with near future experiments. This provides a powerful probe of the hidden sectors and, as a consequence, of the string theory realisation itself. In the present paper, we show, using a variety of methods, how the kinetic mixing can be derived from the underlying type II string compactification, involving supersymmetric and nonsupersymmetric configurations of D-branes, both in large volumes and in warped backgrounds with fluxes. We first demonstrate by explicit example that kinetic mixing occurs in a completely supersymmetric set-up where we can use conformal field theory techniques. We then develop a supergravity approach which allows us to examine the phenomenon in more general backgrounds, where we find that kinetic mixing is natural in the context of flux compactifications. We discuss the phenomenological consequences for experiments at the low-energy frontier, searching for signatures of light, sub-electronvolt or even massless hidden-sector U(1) gauge bosons and minicharged particles.