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arXiv 0806.1735astro-ph
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宇宙学中微子是自由流吗?

Are cosmological neutrinos free-streaming?

Anders Basboll, Ole Eggers Bjaelde, Steen Hannestad, Georg G. Raffelt

摘要:

来自宇宙学的精确数据表明,中微子自由流动,因此在复合时期相互作用非常弱。我们在一个简单的框架下研究这个问题,即中微子瞬间重新耦合,并在红移z_i处停止自由流动。最新的宇宙学数据表明z_i < 1500,确切的约束在一定程度上取决于z_i的假设先验。这一界限转化为中微子与类Majoron粒子之间耦合强度的极限,意味着在nu_2 -> nu_1+phi衰变中τ> 1 x 10^10 s(m_2/50 meV)^3。

英文摘要:

Precision data from cosmology suggest neutrinos stream freely and hence interact very weakly around the epoch of recombination. We study this issue in a simple framework where neutrinos recouple instantaneously and stop streaming freely at a redshift z_i. The latest cosmological data imply z_i < 1500, the exact constraint depending somewhat on the assumed prior on z_i. This bound translates into a limit on the coupling strength between neutrinos and majoron-like particles phi, implying tau > 1 x 10^10 s (m_2/50 meV)^3 for the decay nu_2 -> nu_1+phi.

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