早期宇宙中的$SU(\mathcal{N})$重子形成与暗物质
$SU(\mathcal{N})$ baryon formation in the early Universe and dark matter
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中文总结 AI 辅助
研究早期宇宙$SU(\mathcal{N})$规范理论中重子形成，发现Casimir瓶颈抑制大$\mathcal{N}$下重子产额，其遗迹密度可解释暗物质，所需质量远超幺正性界限。
中文摘要 AI 辅助
我们研究了在包含基础表示夸克、质量在禁闭尺度附近或以下的$SU(\mathcal{N})$规范理论的禁闭交叉过程中，$\mathcal{N}$夸克重子的形成。我们假设通过夸克团簇对的连续融合实现逐步重子形成，其中颜色相互作用速率服从二次Casimir标度。我们考虑了$SU(\mathcal{N})$反对称团簇（带有其特定的自旋-味道多重性）之间的完整反应集合。我们证明，在大的$\mathcal{N}$下，重子形成受到Casimir瓶颈的阻碍，使得重子组装链初始步骤中少夸克团簇的融合被团簇破坏过程强烈压倒。我们发现，对于$\mathcal{N}=12\\,(18)$，重子与介子产额比被抑制到其在$\mathcal{N}=3$时值的$10^{-12}\\,(10^{-23})$。我们将该机制嵌入一个矢量型三味模型，其最轻重子可以是电中性的，而轴向反常诱导的耦合和维度六算子诱导不稳定介子和带电重子在太初核合成之前安全地衰变。因此，宇宙学稳定的中性$\mathcal{N}$重子的遗迹密度在禁闭期间被设定为如此小的值，以至于对于足够大的$\mathcal{N}$，饱和暗物质能量密度所需的重子质量超过湮灭截面幺正性界限好几个数量级。
英文摘要
We study the formation of $\mathcal{N}$-quark baryons during the confinement crossover of an $SU(\mathcal{N})$ gauge theory containing quarks in the fundamental representation, with masses around or below the confinement scale. We assume stepwise baryon formation through the successive fusion of pairs of quark-clusters, with color interaction rates obeying quadratic Casimir scaling. We include the complete set of reactions between $SU(\mathcal{N})$ antisymmetric clusters dressed with their specific spin-flavor multiplicities. We show that at large $\mathcal{N}$, baryon formation is hindered by a Casimir bottleneck, such that fusion of few-quark clusters in the initial steps of the baryon assembly chain is strongly outweighed by cluster destruction processes. We find that for $\mathcal{N}=12\,(18)$ the baryon-to-meson yield ratio is suppressed down to $10^{-12}\,(10^{-23})$ of its value at $\mathcal{N}=3$. We embed the mechanism in a vectorlike three-flavor model whose lightest baryon can be electrically neutral, while axial-anomaly-induced couplings and dimension-six operators induce decays of the unstable mesons and charged baryons safely before big-bang nucleosynthesis. The relic density of cosmologically stable neutral $\mathcal{N}$-baryons is thus set during confinement at values so small that, for sufficiently large $\mathcal{N}$, the baryon masses required to saturate the dark matter energy density exceed by several orders of magnitude the unitarity bound on annihilation cross sections.
发表机构
- INFN Sezione di Padova（意大利国家核物理研究所帕多瓦分部）
- SISSA, International School for Advanced Studies（国际高等研究学院）
- INFN, Sezione di Trieste（意大利国家核物理研究所的里雅斯特分部）
- Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati（意大利国家核物理研究所弗拉斯卡蒂国家实验室）
- Laboratory of High Energy and Computational Physics, NICPB（爱沙尼亚自然科学院高能计算物理实验室）
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