1 Introduction 1.1 Historical Review 1.2 Motivation 1.3 Non-standard Approaches to BBN 1.4 Structure of This Text References 2 The Standard Model of Cosmology 2.1 Theory of General Relativity 2.2 The Robertson-Walker Metric 2.3 The Friedmann Equation 2.4 Astronuclear Reactions 2.4.1 Thermonuclear reaction rates 2.4.2 Nonresonant reactions 2.4.3 Resonant reactions 2.4.4 Inverse reactions 2.4.5 Rates of electron capture and b -decay 2.4.6 Reaction rates and their uncertainties 2.5 Standard Big Bang Nucleosynthesis 2.5.1 Overview of SBBN 2.5.2 Numerical calculations of SBBN 2.5.3 Observed abundance of light elements 2.5.4 Neutron lifetime 2.6 Another Observational Success of the Standard Model References 3 Theories Beyond The Standard Model 3.1 Lepton Asymmetry 3.1.1 Reaction rates between neutrons and protons 3.1.2 BBN with degenerate neutrinos 3.1.3 c2 analysis 3.2 BBN under the Brane Cosmology 3.2.1 Five-dimensional Einstein tensor 3.2.2 Friedmann-like equation 3.2.3 BBN on the brane 3.3 Phenomenological Variable L Models References 4 Modified Brans-Dicke Theory 4.1 Dynamics of BDL model 4.2 Parameters in the BDL model 4.3 Characteristics of a flat universe 4.4 Constraints on the BDL Model 4.4.1 Constraints from BBN 4.4.2 Constraints from SNe Ia References 5 Appendix A: Einstein Tensor 6 Appendix B: Thermal History in an Early Universe 7 Appendix C: Numerical Approach to Calculate Nucleosynthesis References 8 Appendix D: Some Useful Numbers Index ukryj opis