Discovery of strong progenitor age dependence of type Ia supernova
  luminosity standardization process and discordance in cosmology
  Supernova (SN) cosmology is based on the assumption that the width-luminosity
relation (WLR) and the color-luminosity relation (CLR) in the type Ia SN
luminosity standardization would not vary with progenitor age. Unlike this
expectation, recent age datings of stellar populations in host galaxies have
shown significant correlations between progenitor age and Hubble residual (HR).
It was not clear, however, how this correlation arises from the SN luminosity
standardization process, and how this would impact the cosmological result.
Here we show that this correlation originates from a strong progenitor age
dependence of the WLR and the CLR, in the sense that SNe from younger
progenitors are fainter each at given light-curve parameters $x_1$ and $c$.
This is reminiscent of Baade's discovery of two Cepheid period-luminosity
relations, and, as such, causes a serious systematic bias with redshift in SN
cosmology. Other host properties show substantially smaller and insignificant
differences in the WLR and CLR for the same dataset. We illustrate that the
differences between the high-$z$ and low-$z$ SNe in the WLR and CLR, and in HR
after the standardization, are fully comparable to those between the
correspondingly young and old SNe at intermediate redshift, indicating that the
observed dimming of SNe with redshift is most likely an artifact of
over-correction in the luminosity standardization. When this systematic bias
with redshift is properly taken into account, there is no or little evidence
left for an accelerating universe, posing a serious question to one of the
cornerstones of the concordance model.
