1205.6304 (Seokcheon Lee)

Evidence for departure from ΛCDM with LSS    [PDF]

Seokcheon Lee

We investigate the growth index parameter \gamma and the time variation of the gravitational constant G_{eff} by using the currently available growth function f(z) data at different redshifts, consistently scaled to the fiducial \Lambda CDM model. We inquire the four different models of \gamma including a constant \gamma model. From a \chi^2 minimization, we constrain the parameter spaces of models and show that \Lambda CDM model is excluded by 1-\sigma level from current f(z) data. G_{eff} is different from the Newton's gravitational constant G_{N} in modified gravity theories and interestingly, the current data shows that G_{eff} \neq G_{N} at z \gtrsim 0.3 with 3-\sigma level. From these, we conclude that Einstein's General Relativity with \Lambda CDM is ruled out by 99 % confidence level from large scale structure (LSS) observations.

View original: http://arxiv.org/abs/1205.6304