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Astron. Astrophys. 325, 893-897 (1997)

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Age of the universe constrained from the primordial nucleosynthesis in the Brans-Dicke theory with a varying cosmological term

T. Etoh 1, M. Hashimoto 1, K. Arai 2 and S. Fujimoto 2

1 Department of Physics, Kyushu University, Ropponmatsu, Fukuoka 810, Japan
2 Department of Physics, Kumamoto University, Kurokami, Kumamoto 860, Japan

Received 14 February 1997 / Accepted 4 April 1997


The age of the universe is investigated from a viewpoint of the primordial nucleosynthesis in the Brans-Dicke model with a varying [FORMULA] term. It is shown that the age can be long enough compared with that of the globular clusters using two critical quantities recently reported from the HST observations: the Hubble constant, and deuterium abundances. Then it is shown that the present rate of variation in the gravitational "constant" can be predicted.

From the observational constraint in the primordial nucleosynthesis, the baryon density relative to the critical density is found to be [FORMULA] from the observation by Songaila et al. (1996) and [FORMULA] from that by Tytler et al. (1996), where the critical density is [FORMULA] g cm-3 for [FORMULA] = 80 km s-1 Mpc-1 and a parameter characteristic to the Brans-Dicke theory. It is concluded that most of the matter consists of the non-baryonic dark matter if the universe is flat.

Key words: cosmology: dark matter – early universe – general: nuclear reactions – nucleosynthesis – abundances

Send offprint requests to: M. Hashimoto Present address: Hitachi Software Engineering Corporation, Ogami, Yokohama 231, Japan


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© European Southern Observatory (ESO) 1997

Online publication: April 28, 1998