We examine nonrelativistic particles that decay into relativistic products in big rip, little rip, and pseudorip models for the future evolution of the Universe. In contrast to decays that occur in standard $\mathrm{\Lambda }\mathrm{CDM}$, the evolution of the ratio $r$ of the energy density of the relativistic decay products to the energy density of the initially decaying particles can decrease with time in all of these models. In big rip and little rip models, $r$ always goes to zero asymptotically, while this ratio evolves to infinity or a constant in pseudorip models.

中文翻译：

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未来宇宙膨胀的各种场景中衰变粒子和衰变产物的演化

我们在宇宙未来演化的大裂隙、小裂隙和伪裂隙模型中研究了衰变成相对论产物的非相对论粒子。与标准中发生的衰变相反$\mathrm{\Lambda }\mathrm{清洁发展机制}$, 比率的演变 $r$在所有这些模型中，相对论衰变产物的能量密度与初始衰变粒子的能量密度之比会随时间降低。在大撕裂和小撕裂模型中，$r$ 总是渐近地变为零，而这个比率在伪撕裂模型中演变为无穷大或常数。