BBN: Theory vs Observations

• Predictions: Schramm plot (BDF 2011)
• Concordance? (BDF, Molaro, & Sarkar 2013)

BBN: Implications

• baryon density
• dark matter: two kinds!
  • baryonic dark matter: e.g., hot gas in collapsed structures and intergalactic gas; MACHOs (well, probably not MACHOs)
  • non-baryonic dark matter

BBN in Light of the CMB

• Overview: BBN+CMB Schramm plot
• Standard BBN: Light element CMB predictions vs observations (update to CFO 2008)

BBN Beyond the Standard Model

• relaxing and testing assumptions
• counting relativistic degrees of freedom: the effective number of neutrinos (Steigman, Schramm, and Gunn 1977)