arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2409.05027hep-phastro-ph.COgr-qc
收藏

标量子暗物质与宇宙的热历史

Scalaron dark matter and the thermal history of the universe

Yuri Shtanov

AI总结:

该研究改进了度规$f(R)$引力中标量子暗物质的演化分析,纳入平滑电弱交叉效应,验证小质量标量子振荡仍可被激发,且量子色动力学迹反常对其宇宙学场景影响不显著。

摘要:

在与标准模型最小耦合的度规$f(R)$引力中,若标量子(scalaron)场的质量处于$\text{meV} \lesssim m \lesssim \text{MeV}$的范围,它可作为暗物质候选体。标量子的演化受应力-能量张量迹的影响,正如我们此前工作所示,该张量迹的行为在电弱交叉过程中会变为非绝热的,可能触发标量子振荡。尽管我们此前将该交叉近似为单圈阶的二级相变,但该转变实际上更为平滑。本文中我们改进了分析以纳入这种平滑交叉效应,并证明只要标量子质量足够小,在数值格点模拟观测到的电弱交叉的快速动力学驱动下,标量子振荡仍会以定性相似的方式被激发。我们还研究了量子色动力学的迹反常对应力-能量张量迹的时间相关贡献。结果表明,尽管迹反常会改变标量子的平衡值,但与标量子的快速振荡相比,这种改变是绝热演化的,意味着迹反常不会显著影响标量子演化的潜在宇宙学场景。

英文摘要:

In metric $f(R)$ gravity minimally coupled to the Standard Model, the scalaron field can act as a dark-matter candidate if its mass lies in the range $\text{meV} \lesssim m \lesssim \text{MeV}$. The evolution of the scalaron is influenced by the trace of the stress-energy tensor, whose behaviour, as shown in our previous work, becomes non-adiabatic during the electroweak crossover, potentially triggering scalaron oscillations. While we previously approximated this crossover as a second-order phase transition at the one-loop level, the transition is actually smoother. In this paper, we refine our analysis to account for this smooth crossover and show that scalaron oscillations are still excited in a qualitatively similar manner, driven by the rapid dynamics of the electroweak crossover observed in numerical lattice simulations, provided the scalaron mass is sufficiently small. We also investigate the time-dependent contribution to the stress-energy trace due to the trace anomaly of quantum chromodynamics. Our results indicate that, while the trace anomaly shifts the scalaron's equilibrium value, this shift evolves adiabatically compared to the fast oscillations of the scalaron, meaning that the trace anomaly does not significantly affect the potential cosmological scenarios for scalaron evolution.

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。

↑