Quark-Hadron Phase Transition and Nucleosynthesis in Early Universe

近年来对非均匀宇宙核合成的研究指出：1)OMEGA_B=1模型与轻元素观测结果一致；2)重元素（包括r过程元素）大量合成；3)由于^9Be也大量合成，因此^9Be起着非均匀性的指示作用。然而，这些建议是基于一个简单的两区模型，在这个模型中，在核合成过程中忽略了中子的反向扩散。本研究表明：1)与轻元素观测相符的OMEGA_B的上限与均匀情况几乎相同，OMEGA_B=0.06h^<-2>; 2)简单双区模型的^9Be丰度在合理参数空间中至少高估了两个数量级；3)CNO元素的丰度在与轻元素丰度相符的重子/光子比的适当范围内非常小。

From recent studies of nucleosynthesis in inhomogeneous universe, it has been pointed out that 1) OMEGA_B=1model becomes consistent with light element observations, 2) heavy elements including r-process elements are abundantly synthesized, and 3) ^9Be plays a role of the indicator of inhomogeneity since ^9Be is also abundantly synthesized. These suggestions were, however, based on a simple two-zone model in which back diffusion of neutrons are neglected during the nucleosynthesis. In the present investigation, it was shown that 1) the upper limit of OMEGA_B which is consistent with light element observations is almost the same as that of homogeneous case, OMEGA_B=0.06h^<-2>,2) the ^9Be abundance in the simple two-zone model is overestimated at least two orders of magnitude in plausible parameter space and 3) the abundances of CNO elements are very small in the proper range of baryon/photon ratio consistent with the abundances of light elements.