标题： 平坦子模型中相对论轴子的丰富性 显示英文标题

标题： The abundance of relativistic axions in a flaton model of Peccei-Quinn symmetry

摘要： 扁平子模型的Peccei-Quinn对称性具有良好的粒子物理动机，并可能导致热膨胀，从而产生明确的宇宙学。它们可以解决$\mu$问题，并生成可行的中微子质量。标准扁平子模型预测轴子衰变常数F_a约为10^{10}GeV，而通用扁平子模型给出的F_a约为10^9 GeV，这符合观测要求。在所有情况下，轴子都是冷暗物质的良好候选者，因为如果F_a大于10^{12}GeV，其密度会因扁平子衰变而被稀释。除了暗物质轴子外，由扁平子衰变产生的相对论性轴子，在核合成时期相当于一些数量\delta N_\nu 的额外中微子种类。专注于包含三个扁平子粒子和两个扁平子微子的标准模型，我们评估了所有扁平子-扁平子微子-轴子相互作用以及相应的轴子衰变率。它们与DFSZ和KSVZ模型中的主要强子衰变率进行了比较。这些公式为根据参数（质量与耦合）精确计算等效的\delta N_\nu 提供了基础。 KSVZ情况可能已经由现有的限制\delta N_\nu \lsim 1 排除。 DFSZ情况在参数空间的显著区域内是允许的，并将为任何未来检测到的非零$\delta N_\nu$提供可能的解释。 显示英文摘要

摘要： Flaton models of Peccei-Quinn symmetry have good particle physics motivation, and are likely to cause thermal inflation leading to a well-defined cosmology. They can solve the $\mu$ problem, and generate viable neutrino masses. Canonical flaton models predict an axion decay constant F_a of order 10^{10} GeV and generic flaton models give F_a of order 10^9 GeV as required by observation. The axion is a good candidate for cold dark matter in all cases, because its density is diluted by flaton decay if F_a is bigger than 10^{12} GeV. In addition to the dark matter axions, a population of relativistic axions is produced by flaton decay, which at nucleosynthesis is equivalent to some number \delta N_\nu of extra neutrino species. Focussing on the canonical model, containing three flaton particles and two flatinos, we evaluate all of the flaton-flatino-axion interactions and the corresponding axionic decay rates. They are compared with the dominant hadronic decay rates, for both DFSZ and KSVZ models. These formulas provide the basis for a precise calculation of the equivalent \delta N_\nu in terms of the parameters (masses and couplings). The KSVZ case is probably already ruled out by the existing bound \delta N_\nu\lsim 1. The DFSZ case is allowed in a significant region of parameter space, and will provide a possible explanation for any future detection of nonzero $\delta N_\nu$.