Can non-standard recombination resolve the Hubble tension?

作者：MiaoXin Liu,ZhiQi Huang,XiaoLin Luo,HaiTao Miao,Naveen KSingh,Lu Huang

摘要：The inconsistent Hubble constant values derived from cosmic microwave background(CMB) observations and from local distance-ladder measurements may suggest new physics beyond the standard ΛCDM paradigm. It has been found in earlier studies that, at least phenomenologically, non-standard recombination histories can reduce the ≥4σ Hubble tension to ~ 2σ.Following this path, we vary physical and phenomenological parameters in RECFAST, the standard code to compute ionization history of the universe, to explore possible physics beyond standard recombination. We find that the CMB constraint on the Hubble constant is sensitive to the hydrogen ionization energy and 2 s → 1 s two-photon decay rate, both of which are atomic constants, and is insensitive to other details of recombination. Thus, the Hubble tension is very robust against perturbations of recombination history, unless exotic physics modifies the atomic constants during the recombination epoch.

发文机构：School of Physics and Astronomy

关键词：COSMOLOGYHUBBLErecombinationCMB

分类号： P159[天文地球—天文学]