Big Bang Nucleosynthesis and Tensor-Scalar Gravity

摘要

Big Bang Nucleosynthesis (BNN) is studied within the framework of a two-parameter211u001efamily of tensor-scalar theories of gravitation. The authors run a BBN code 211u001emodified by tensor-scalar gravity, and impose that the theoretically predicted 211u001eBBN yields of Deuterium, Helium and Lithium lie within some conservative 211u001eobservational ranges. It is found that large initial values of a(sub theta) 211u001e(corresponding to initial cosmological expansion rates much larger than the 211u001estandard) are compatible with observed BBN yields. However, BBN-inferred upper 211u001ebound on the cosmological baryon density is insignificantly modified by 211u001econsidering tensor-scalar gravity.