Cosmological model-independent test of two-point diagnostic by the observational Hubble parameter data [CEA]

Aiming at exploring the nature of dark energy (DE), we use forty-three observational Hubble parameter data (OHD) in the redshift range $0 \leqslant z \leqslant 2.36$ to make a cosmological model-independent test of the two-point $Omh^2(z_{2};z_{1})$ diagnostic. In $\Lambda$CDM model, with equation of state (EoS) $w=-1$, $Omh^2 \equiv \Omega_m h^2$ holds to be tenable, where $\Omega_m$ is the matter density parameter, and $h$ is Hubble parameter at present. Since the direct exploitation of OHD to the $Omh^2(z_{2};z_{1})$ diagnostic generate an obscure images, which is bad for analysis, we utilize two methods: the weighted mean and median statistics to bin the data categorically. The binning methods turn out to be promising and considered to be robust. By applying the $Omh^2(z_{2};z_{1})$ diagnostic into binned data, we find that the values of $Omh^2$ fluctuate as the consistent redshift intervals change, i.e., not being constant, and especially significant for the weighted mean case. Therefore, we conclude that the $\Lambda$CDM model is in doubt and other dynamical DE models with an evolving EoS should be considered more likely to be the candidates that interpret the acceleration expansion of the universe.

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S. Cao, X. Duan, X. Meng, et. al.
Wed, 6 Dec 17

Comments: 14 pages, 7 figures. arXiv admin note: text overlap with arXiv:1507.02517