arXiv 1208.00322012-08hep-phastro-ph.COnucl-exnucl-th

中微子与大爆炸核合成

Neutrinos And Big Bang Nucleosynthesis

Gary Steigman

备注：: Invited Review article for the Special Issue on Neutrino Physics, Advances in High Energy Physics, 25 pages, 10 figures
发表信息：: Advances in High Energy Physics, 2012 (2012) 268321
DOI：: 10.1155/2012/268321

摘要：

根据粒子物理学和宇宙学的标准模型，当前宇宙中应该存在类似于宇宙微波光子背景的宇宙中微子背景。弱相互作用的弱点使得中微子背景无法用现有技术检测到。然而，宇宙中微子背景可以通过它对大爆炸核合成（BBN）和宇宙微波背景（CMB）辐射的宇宙学效应间接探测。在这篇BBN评论中，重点关注中微子，更一般地说是暗辐射，对“等效中微子”（暗辐射）的数量，重子不对称性（重子密度）和可能的轻子不对称性（中微子简并度）的BBN约束进行了审查和更新。BBN对暗辐射和重子密度的限制来自于对氘和氦-4的原始丰度的考虑，与CMB的互补结果非常一致，提供了一个暗示性的，但目前还没有定论的暗辐射存在的暗示，它们限制了任何轻子的不对称性。对于这里考虑的所有情况，都存在一个“锂问题”：BBN预测的锂丰度超过观测推断的原始值约3倍。

英文摘要：

According to the standard models of particle physics and cosmology, there should be a background of cosmic neutrinos in the present Universe, similar to the cosmic microwave photon background. The weakness of the weak interactions renders this neutrino background undetectable with current technology. The cosmic neutrino background can, however, be probed indirectly through its cosmological effects on big bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) radiation. In this BBN review, focused on neutrinos and, more generally on dark radiation, the BBN constraints on the number of "equivalent neutrinos" (dark radiation), on the baryon asymmetry (baryon density), and on a possible lepton asymmetry (neutrino degeneracy) are reviewed and updated. The BBN constraints on dark radiation and on the baryon density following from considerations of the primordial abundances of deuterium and helium-4 are in excellent agreement with the complementary results from the CMB, providing a suggestive, but currently inconclusive, hint of the presence of dark radiation and, they constrain any lepton asymmetry. For all the cases considered here there is a "lithium problem": the BBN-predicted lithium abundance exceeds the observationally inferred primordial value by a factor of ~3.

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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