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arXiv 0909.3026hep-phastro-ph.CO
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非标准宇宙学中的冷暗物质,PAMELA,ATIC和费米LAT

Cold Dark Matter in non-Standard Cosmologies, PAMELA, ATIC and Fermi LAT

C. Pallis

摘要:

我们考虑两个非标准的宇宙学模型,根据该模型,宇宙在标量场晚期衰变后被重新加热到一个较低的重新加热温度,或者在跟踪经典模型的背景下被经典场的动能所支配。在这两种情况下,我们计算的遗迹密度的\emph{Weakly Interacting Massive Particles}(WIMPs),并表明,它可以提高其在标准宇宙学的价值。通过调整低再加热或典型方案的参数,宇宙中冷的暗物质丰度可以与大的湮灭截面乘以WIMP速度的值相兼容。利用这些值,并假设WIMP主要湮灭为$e^+e^-$、$μ^+μ^-$或$τ^+τ^-$,我们计算了$e^\pm$宇宙线的感生通量,并拟合了PAMELA和ATIC或Fermi LAT的当前数据。我们实现了相当好的拟合,特别是PAMELA和费米-LAT数据结合的宇宙微波背景产生的限制,只要WIMP湮灭主要是$μ^+μ^-$的边缘履行。在这两种非标准温度下,到传统辐射主导时代所需的转变温度都低于约$0.7 \GeV$。在低再加热的情况下,一个可观的非热贡献的WIMP遗迹密度也是必要的。

英文摘要:

We consider two non-standard cosmological scenaria according to which the universe is reheated to a low reheating temperature after the late decay of a scalar field or is dominated by the kinetic energy of a quintessence field in the context of a tracking quintessential model. In both cases, we calculate the relic density of the \emph{Weakly Interacting Massive Particles} (WIMPs) and show that it can be enhanced with respect to its value in the standard cosmology. By adjusting the parameters of the low reheating or the quintessential scenario, the cold dark matter abundance in the universe can become compatible with large values for the annihilation cross section times the velocity of the WIMPs. Using these values and assuming that the WIMPs annihilate predominantly to $e^+e^-$, $μ^+μ^-$ or $τ^+τ^-$, we calculate the induced fluxes of $e^\pm$ cosmic rays and fit the current data of PAMELA and ATIC or Fermi LAT. We achieve rather good fits especially to PAMELA and Fermi-LAT data in conjunction with a marginal fulfillment of the restriction arising from cosmic microwave background, provided that the WIMPs annihilate predominantly to $μ^+μ^-$. In both non-standard scenaria the required transition temperature to the conventional radiation dominated era turns out to be lower than about $0.7 \GeV$. In the case of the low reheating, an appreciable non-thermal contribution to the WIMP relic density is also necessitated.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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