Decaying Dark Matter and the PAMELA Anomaly
Decaying Dark Matter and the PAMELA Anomaly
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DOI：
10.1088/1475-7516/2009/02/021
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发表时间：
2008-11
影响因子：
6.4
通讯作者：
A. Ibarra;D. Tran
中科院分区：
文献类型：
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作者：
A. Ibarra;D. Tran
天体物理学和宇宙学的观测并不要求暗物质粒子是绝对稳定的。如果它们确实是不稳定的，那么它们衰变成正电子的速率可能足够大，从而可以通过对宇宙正电子通量的异常贡献来间接探测暗物质。在本文中，我们讨论了PAMELA合作最近报道的衰变暗物质的情况下，在正电子分数过剩的影响。为此，我们已经进行了一个模型独立的分析可能的签名，通过研究各种衰变通道的情况下，一个费米子和标量暗物质粒子。我们发现，PAMELA测量的能量大于10 GeV的正电子分数的急剧上升，自然可以容纳在几个实现的衰变暗物质的情况。数据指向一个相当重的暗物质粒子，m{sub DM} {approx}> 300 GeV，它优先直接衰变为第一代或第二代带电轻子，寿命{tau}{sub DM} {approx} 10{sup 26} s。
Astrophysical and cosmological observations do not require the dark matter particles to be absolutely stable. If they are indeed unstable, their decay into positrons might occur at a sufficiently large rate to allow the indirect detection of dark matter through an anomalous contribution to the cosmic positron flux. In this paper we discuss the implications of the excess in the positron fraction recently reported by the PAMELA collaboration for the scenario of decaying dark matter. To this end, we have performed a model-independent analysis of possible signatures by studying various decay channels in the case of both a fermionic and a scalar dark matter particle. We find that the steep rise in the positron fraction measured by PAMELA at energies larger than 10 GeV can naturally be accommodated in several realizations of the decaying dark matter scenario. The data point toward a rather heavy dark matter particle, m{sub DM} {approx}> 300 GeV, which preferentially decays directly into first or second generation charged leptons with a lifetime {tau}{sub DM} {approx} 10{sup 26} s.