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| Paper IPM / Physic / 8528 |
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| Abstract: | |||||
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There exist many observational evidences implying the expansion of
our universe is undergoing a late-time acceleration, the mechanism
of this acceleration is yet unknown. In the so-called thick brane
model this phenomena is attributed to the thickness of the brane
along the extra dimension. In this study we mainly rely to the
consistency of this model with most recent observational data
related to the background evolution. The new Supernova Type Ia
(SNIa) Gold sample and Supernova Legacy Survey (SNLS) data, the
position of the acoustic peak at the last scattering surface from
the WMAP observations and the baryon acoustic oscillation peak found
in the Sloan Digital Sky Survey (SDSS) are used to constrain the
free parameter of the thick codimension 1 brane model. To infer
its consistency with age of our universe, we compare the age of old
cosmological objects with what computed using the best fit values
for the model parameters. When the universe is matter dominated,
w=0, at 68% level of confidence, the combination of Gold sample
SNIa, CMB shift parameter and SDSS databases provides
Ωm=0.31−0.02+0.02,
ΩC=0.05−0.01+0.01,
wr=−1.40−0.20+0.20, hence a spatially open universe with
Ωk=0.21−0.08+0.08. The same combination with SNLS
supernova observation gives Ωm=0.28−0.02+0.03,
ΩC=0.037−0.004+0.003,
wr=−2.05−0.15+0.15 consequently provides a spatially open
universe Ωk=0.11−0.07+0.10. These results obviously
seem to be in contradiction with the most recent WMAP results
indicating a flat
universe.
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