发表机构
Vellore Institute of Technology（维洛尔理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究在平坦与非平坦$\rm \u039CDM$、$w_0w_a\rm CDM$宇宙学框架下，利用多组观测数据约束含部分热化eV量级惰性中微子的(3+1)中微子模型，发现非平坦$w_0w_a\rm CDM$模型可显著改善拟合度，且对开放空间几何有2.8$\u03C3$的偏好。
AI 中文摘要
我们研究包含额外部分热化电子伏特（eV）量级惰性中微子与三种活性中微子的(3+1)中微子框架的宇宙学约束。未假设完全热化，而是允许惰性中微子的丰度通过其物理质量$m_s$和对相对论性物种有效数的贡献$\triangle N_{\rm eff}$独立变化。该惰性态被建模为温度低于活性中微子背景的热分布非冷遗迹。我们考虑平坦与非平坦$\rm \u039CDM$以及$w_0w_a\rm CDM$宇宙学，均包含相同的(3+1)$\nu$部分。利用Planck 2018 CMB数据、DESI DR2 BAO、Pantheon+ Ia型超新星、保守的$f\rm \u03C3_8$测量汇编及最新的H0DN对这些模型进行约束。对活性中微子质量分裂施加振荡先验，而eV量级惰性中微子质量范围由短基线振荡搜索和全局(3+1)分析确定。我们发现，允许晚期宇宙学背景的额外自由度会显著改变推断出的惰性中微子部分：有效惰性质量从平坦$\rm \u039CDM+(3+1)\nu$中的$m_{s,\rm eff}\backsim0.11\rm \u00B10.05\rm eV$增加到非平坦$w_0w_a\rm CDM+(3+1)\nu$模型中的$\backsim0.35\rm \u00B10.12\rm eV$；对应的惰性丰度从$\triangle N_{\rm eff}\u22640.1$变为$\triangle N_{\rm eff}\backsim0.35\rm \u00B10.15$，仍远低于完全热化极限$\triangle N_{\rm eff}\backsim1$。非平坦$w_0w_a\rm CDM$模型还显示出约2.8$\u03C3$的开放空间几何偏好，$\u03A9_k\backsim0.0045\rm \u00B10.0016$，并给出$H_0\backsim70.9\rm \u00B10.7\rm km\thinspace s^{-1}\thinspace Mpc^{-1}$和$S_8\backsim0.785\rm \u00B10.015$；这些模型相比平坦$\rm \u039CDM+(3+1)\nu$将最小$\u03C7^2$改善了约21至25。
英文摘要
We investigate cosmological constraints on a $(3+1)$ neutrino framework containing an additional partially thermalized, eV-scale sterile neutrino alongside the three active species. Rather than assuming full thermalization, we allow the sterile abundance to vary independently through its physical mass $m_s$ and contribution $ΔN_{\rm eff}$ to the effective number of relativistic species. The sterile state is modeled as a thermally distributed non-cold relic with a temperature below that of the active-neutrino background. We consider flat and non-flat $Λ$CDM and $w_0w_a$CDM cosmologies, all including the same $(3+1)ν$ sector. The models are constrained using Planck 2018 CMB data, DESI DR2 BAO, Pantheon+ Type Ia supernovae, a conservative compilation of $fσ_8$ measurements, and the recent H0DN. Oscillation-informed priors are imposed on the active-neutrino mass splittings, while the eV scale sterile-mass range is motivated by short-baseline oscillation searches and global $(3+1)$ analyses. We find that allowing additional freedom in the late-time cosmological background substantially changes the inferred sterile-neutrino sector. The effective sterile mass increases from $m_{s,\rm eff}\sim0.11\pm0.05~{\rm eV}$ in flat $Λ$CDM$+(3+1)ν$ to $\sim0.35\pm0.12~{\rm eV}$ in the non-flat $w_0w_a$CDM$+(3+1)ν$ model. The corresponding sterile abundance shifts from $ΔN_{\rm eff}\lesssim0.1$ to $ΔN_{\rm eff}\simeq0.35\pm0.15$, while remaining well below the fully thermalized limit, $ΔN_{\rm eff}\simeq1$. The non-flat $w_0w_a$CDM models also show $\sim 2.8σ$ preference for open spatial geometry, $Ω_k\simeq0.0045\pm0.0016$, and yield $H_0\simeq70.9\pm0.7~{\rm km\,s^{-1}\,Mpc^{-1}}$ and $S_8\simeq0.785\pm0.015$. These models improve the minimum $χ^2$ by approximately $21$-$25$ relative to flat $Λ$CDM$+(3+1)ν$.
Comments18 pages, 7 caption figures
