REVISED BIG BANG NUCLEOSYNTHESIS WITH LONG-LIVED, NEGATIVELY CHARGED MASSIVE PARTICLES: UPDATED RECOMBINATION RATES, PRIMORDIAL 9Be NUCLEOSYNTHESIS, AND IMPACT OF NEW 6Li LIMITS-猫眼课题宝

DOI：

10.1088/0067-0049/214/1/5

发表时间：

2014-03

期刊：

The Astrophysical Journal Supplement Series

影响因子：

--

通讯作者：

中科院分区：

其他

文献类型：

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作者：

M. Kusakabe;M. Kusakabe;K. S. Kim;M. Cheoun;T. Kajino;Y. Kino;G. Mathews

我们广泛地重新分析了长寿命、带负电的大质量粒子X−对大爆炸核合成（BBN）的影响。带X -粒子的BBN模型最初是由标准BBN模型中预测的6,7 li丰度与从金属贫乏恒星观测推断的丰度之间的差异所驱动的。在这个模型中，7Be通过与X -粒子的重组和辐射质子捕获而被破坏。我们计算了7Be、7Li、9Be和4He与X−的辐射复合的精确速率。在非共振速率下，我们考虑了散射态和束缚态各自的部分波。核荷分布的有限尺寸导致波函数与点电荷核的波函数存在偏差。对于重X−质量，mX > 100gev， d波→2P跃迁对7Li和7,9be来说是最重要的，不像与电子的复合。在mX = 1000 GeV条件下，7Be复合的非共振速率比现有的速率大6倍以上。此外，我们还提出了一个新的重要的9Be生成反应：7Li和X -的重组，然后是氘核捕获。我们推导出X原子核的结合能以及反应速率和Q值。然后我们计算了BBN，发现7Be的破坏量在很大程度上取决于7Be的电荷分布。最后，在修正的原始6Li丰度上限的背景下，导出了X−初始丰度和寿命的最新约束。修正了7Li问题和原始9Be丰度解的参数区域。

We extensively reanalyze the effects of a long-lived, negatively charged massive particle, X−, on big bang nucleosynthesis (BBN). The BBN model with an X− particle was originally motivated by the discrepancy between the 6, 7Li abundances predicted in the standard BBN model and those inferred from observations of metal-poor stars. In this model, 7Be is destroyed via the recombination with an X− particle followed by radiative proton capture. We calculate precise rates for the radiative recombinations of 7Be, 7Li, 9Be, and 4He with X−. In nonresonant rates, we take into account respective partial waves of scattering states and respective bound states. The finite sizes of nuclear charge distributions cause deviations in wave functions from those of point-charge nuclei. For a heavy X− mass, mX ≳ 100 GeV, the d-wave → 2P transition is most important for 7Li and 7, 9Be, unlike recombination with electrons. Our new nonresonant rate of the 7Be recombination for mX = 1000 GeV is more than six times larger than the existing rate. Moreover, we suggest a new important reaction for 9Be production: the recombination of 7Li and X− followed by deuteron capture. We derive binding energies of X nuclei along with reaction rates and Q values. We then calculate BBN and find that the amount of 7Be destruction depends significantly on the charge distribution of 7Be. Finally, updated constraints on the initial abundance and the lifetime of the X− are derived in the context of revised upper limits to the primordial 6Li abundance. Parameter regions for the solution to the 7Li problem and the primordial 9Be abundances are revised.