Absence of concordance in a simple self-interacting neutrino cosmology
arxiv(2024)
摘要
Some cosmic microwave background (CMB) data allow a cosmological scenario in
which the free streaming of neutrinos is delayed until close to
matter-radiation equality. Interestingly, recent analyses have revealed that
large-scale structure (LSS) data also align with this scenario, discarding the
possibility of an accidental feature in the CMB sky and calling for further
investigation into the free-streaming nature of neutrinos. By assuming a simple
representation of self-interacting neutrinos, we investigate whether this
nonstandard scenario can accommodate a consistent cosmology for both the CMB
power spectra and the large-scale distribution of galaxies simultaneously.
Employing three different approaches - a profile likelihood exploration, a
nested sampling method, and a heuristic Metropolis-Hasting approximation - we
exhaustively explore the parameter space and demonstrate that galaxy data
exacerbates the challenge already posed by the Planck polarization data for
this nonstandard scenario. We find that the most conservative value of the
Bayes factor disfavors the interactions among neutrinos over a ΛCDM +
N_eff + ∑ m_ν model with odds of 23:1000 and that the
difficulty of simultaneously fitting the galaxy and CMB data relates to the
so-called S_8 discrepancy. Our analysis not only emphasizes the need to
consider a broader range of phenomenologies in the early Universe but also
highlights significant numerical and theoretical challenges ahead in uncovering
the exact nature of the feature observed in the data or, ultimately, confirming
the standard chronological evolution of the Universe.
更多查看译文
AI 理解论文
溯源树
样例
![](https://originalfileserver.aminer.cn/sys/aminer/pubs/mrt_preview.jpeg)
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要