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arXiv 0808.3902hep-phastro-ph
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暗物质粒子质量的下限

A lower bound on the mass of Dark Matter particles

Alexey Boyarsky, Oleg Ruchayskiy, Dmytro Iakubovskyi

摘要:

通过对矮球状星系中暗物质相空间分布的分析,讨论了暗物质粒子质量的边界。在回顾了现有的方法,我们选择了两种方法来推导这样的界限。第一种方法仅依赖于DM粒子当前相空间分布的信息,而第二种方法同时使用初始和最终分布。我们讨论了最近的数据dSphs以及相关参数的天文不确定性。作为一个应用程序,我们提出了较低的边界上的DM粒子的质量,来自不同的dSphs,使用这两种方法。模型无关的约束适用于任何类型的费米子DM。更强的,依赖于模型的界限引用了几个DM模型(热遗迹,非共振和共振产生的不育中微子等)。后者的界限依赖于重子反馈不能显着增加DM粒子的分布函数的最大值的假设。对于所有DM都是由通过与活跃中微子(NRP)的非共振混合产生的无菌中微子组成的情况,这给出了m_nrp > 1.7 keV。将这些结果以最保守的形式与DM衰变线的X射线边界相结合,我们得出结论,NRP方案仅在非常窄的参数窗口中是允许的。该结论与Lyman-alpha分析的结果无关。在DM模型中,在轻子不对称性的存在下共振产生无菌中微子仍然是可行的。在标准模型的最小中微子扩展(nuMSM)中,DM不育中微子的质量和混合角都是上下有界的,这为实验研究提供了可能性。

英文摘要:

We discuss the bounds on the mass of Dark Matter (DM) particles, coming from the analysis of DM phase-space distribution in dwarf spheroidal galaxies (dSphs). After reviewing the existing approaches, we choose two methods to derive such a bound. The first one depends on the information about the current phase space distribution of DM particles only, while the second one uses both the initial and final distributions. We discuss the recent data on dSphs as well as astronomical uncertainties in relevant parameters. As an application, we present lower bounds on the mass of DM particles, coming from various dSphs, using both methods. The model-independent bound holds for any type of fermionic DM. Stronger, model-dependent bounds are quoted for several DM models (thermal relics, non-resonantly and resonantly produced sterile neutrinos, etc.). The latter bounds rely on the assumption that baryonic feedback cannot significantly increase the maximum of a distribution function of DM particles. For the scenario in which all the DM is made of sterile neutrinos produced via non-resonant mixing with the active neutrinos (NRP) this gives m_nrp > 1.7 keV. Combining these results in their most conservative form with the X-ray bounds of DM decay lines, we conclude that the NRP scenario remains allowed in a very narrow parameter window only. This conclusion is independent of the results of the Lyman-alpha analysis. The DM model in which sterile neutrinos are resonantly produced in the presence of lepton asymmetry remains viable. Within the minimal neutrino extension of the Standard Model (the nuMSM), both mass and the mixing angle of the DM sterile neutrino are bounded from above and below, which suggests the possibility for its experimental search.

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