Neutralino dark matter annihilation to monoenergetic gamma rays as a signal of low mass superstrings

We consider extensions of the standard model based on open strings ending on D-branes, in which gauge bosons and their associated gauginos exist as strings attached to stacks of D-branes, and chiral matter exists as strings stretching between intersecting D-branes. Under the assumptions that the fundamental string scale is in the TeV range and the theory is weakly coupled, we study models of supersymmetry for which signals of annihilating neutralino dark matter are observable. In particular, we construct a model with a supersymmetric R-symmetry violating (but R-parity conserving) effective Lagrangian that allows for the s-wave annihilation of neutralinos, once gauginos acquire mass through an unspecified mechanism. The model yields bino-like neutralinos (with the measured relic abundance) that annihilate to a γγ final state with a substantial branching fraction (∼10%) that is orders of magnitude larger than in the minimal supersymmetric standard model. A very bright gamma-ray spectral line could be observed by gamma-ray telescopes.

我们考虑基于终止于D - 膜的开弦对标准模型的扩展，在这种扩展中，规范玻色子及其相关的超伴子作为附着在D - 膜堆上的弦而存在，手征物质作为在相交的D - 膜之间伸展的弦而存在。在基本弦标度处于太电子伏特范围且理论是弱耦合的假设下，我们研究超对称模型，对于这些模型，湮灭中性微子暗物质的信号是可观测的。特别是，我们构建了一个具有违反超对称R - 对称性（但保持R - 宇称）的有效拉格朗日量的模型，一旦超伴子通过一种未指明的机制获得质量，该模型允许中性微子的s - 波湮灭。这个模型产生类似超中性子的中性微子（具有测量到的遗迹丰度），它们湮灭到γγ末态，具有相当大的分支比（约10%），比最小超对称标准模型中的分支比大几个数量级。伽马射线望远镜可能观测到一条非常明亮的伽马射线谱线。