Self-interacting dark matter

暗物质（DM）通常被认为是无碰撞的，然而这只有在它与重子物质相互作用时才有必要。原则上，暗物质可能与自身有很强的相互作用。事实上，这已经被提出，以缓解无碰撞冷暗物质假说在面对小尺度观测数据时的一些问题。此外，在星系团A3827中也有自相互作用的观测迹象，其中一个落入星系团的星系被观测到从其（引力透镜）暗物质晕中位移。这将需要一个大的1 cm^2/gm的自相互作用横截面。我们将研究许多不同模型的DM-DM散射的角分布（例如，对于Dirac DM，矢量交换的角分布与轴向矢量交换的角分布有何不同？）粒子-粒子散射和粒子-反粒子散射有区别吗？)即将到来的观测数据将根据这些发现进行分析。如此大的横截面对对撞机特征的影响也将在ATLAS/CMS工作组正在考虑的“简化模型”框架内进行研究。

Dark matter (DM) is usually assumed to be collisionless, however this is necessary only for its interactions with baryonic matter. In principle dark matter may have strong interactions with itself. This has in fact been suggested to alleviate some problems of the collisionless cold dark matter hypothesis when confronted with observational data on small scales. Moreover there is observational indication for self-interactions in the cluster A3827 where a galaxy falling into the cluster is observed to be displaced from its (gravitationally lensed) dark matter halo. This would require a large self-interaction cross-section of order 1 cm^2/gm.We will study angular distributions of DM-DM scattering for a number of different models (e.g. for Dirac DM, how would the angular distribution for a vector exchange differ from the angular distribution from an axial-vector exchange? Would there be differences between particle-particle scattering and particle-antiparticle scattering?) Forthcoming observational data will be analysed in the light of these findings. The implications of such large cross-sections for collider signatures will also be studied in the framework of 'simplified models' being considered by the ATLAS/CMS working group.