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Big Bang Nucleosynthesis: Theory vs. Observation

This study by Michael S. Turner delves into the comparison between theoretical predictions and observational evidence regarding Big Bang Nucleosynthesis (BBN). It explores the precision of cosmological measurements in relation to the abundance of light elements like deuterium, helium-4, and lithium-7. The analysis covers reactions essential in BBN, and the significance of different isotopes in understanding the early Universe's composition.

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Big Bang Nucleosynthesis: Theory vs. Observation

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  1. Big Bang Nucleosynthesis: Theory vs. Observation TASI 2009 Michael S. Turner 4 June 2009 Michael S Turner

  2. Michael S Turner

  3. Michael S Turner

  4. 0.07 MeV 0.2 MeV 0.01 MeV 1 MeV D leads 10 MeV NSE, n/p~1/6 Thermal Equilibrium BBN Michael S Turner

  5. BBN Reaction Network: the big 12 Michael S Turner

  6. He-4 Prediction (95%): n ↔ p ΔY = ±0.0004 (τn) ±0.0004 (th) -0.002? ΔY = ±0.0002 Δτn/sec τ(n) = 885.7 ± 0.8 sec (±0.1%) …but, Serebrov (2005): 878.5 ± 0.8 sec (-0.8% or -6.5 σ)??##!! Michael S Turner

  7. D/H Prediction (95%): ±8% d(d,n)He-3 and d(p,γ)He-3 Michael S Turner

  8. Li-7 Prediction (95%): ±25% p(n,γ)d, He-3(α,γ)Be-7, d(p,γ)He-3, d(d,n)He-3 Michael S Turner

  9. Reaction Cross Sections are measured where they are needed – no need to extrapolate. Sharp contrast to stellar models Michael S Turner

  10. BBN Predictions • (95% cl) • Deuterium: baryometer! • He-4: go/no-go test of big bang • Li-7: consistency test; • stellar probe? • He-3: probe of chemical evolution Michael S Turner

  11. Light Element AbundancesD, He-4 and Li-7 • Deuterium: stars only destroy D – need pristine samples of the Universe • He-4: MS stars make He-4 – need old, metal poor stars • Li-7: also made by cosmic rays, destroyed by stars, • He-3: made and destroyed by stars, learn more about chemical evolution! Michael S Turner

  12. Michael S Turner

  13. Burles/Tytler, ApJ 499, 699 (1998) Detecting Deuterium Michael S Turner

  14. O’Meara et al: 6 Deuterium Systems D/H = 2.8 ± 0.3 x 10-5 • BBN (Deuterium) • Ωbh2 = 0.0213 ± 0.0013 (D) ± 0.0004 (th) • YP = 0.248 ± 0.005 (D) ± 0.0002 (th) ± 0.0002 (τn)  Li-7/H = 4.3 ± 0.5 x 10-10 -0.002? Michael S Turner

  15. Precision Cosmology Indeed! CMB (first to second peak) Ωbh2 = 0.0225 ± 0.0006 vs. BBN (Deuterium) Ωbh2 = 0.0213 ± 0.0013 ~5% agreement Ωb = 0.044 ± 0.002 h = H0/100 km/s/Mpc ~ 0.7 Michael S Turner

  16. He-4: 0.24x, Struggling for the 3rd Sig Fig YP = 0.248 ± 0.005 (D) ± 0.0004 (th) ± 0.0004 (τn) -0.002? Michael S Turner

  17. He-4: 0.24x, Struggling for the 3rd Sig Fig YP = 0.248 ± 0.005 (D) ± 0.0004 (th) ± 0.0004 (τn) -0.002? • Biggest issue: control of systematic error (see Peimbert, arXiv: 0811.2980) • State of the art, based upon extragalactic HII regions, Peimbert et al, ApJ 666, 636 (2007): YP = 0.2477 ± 0.003 • Concordance with D/BBN prediction Michael S Turner

  18. Li-7: Not as simple as once thought Li-7/H (D/H) = 4.3 ± 0.5 x 10-10 • Spite plateau: Li-7/H = 1.3 ± 0.3 x 10-10 • Factor of 3 discrepancy (for ~10 years)! • Possible explanation: Korn et al, Nature 442, 657 (2006): astration by gravitational settling • Inferred value by Korn et al : (3.5 ± 0.8) x 10-10 Michael S Turner

  19. Selected BBN References • Recent reviews • Schramm/Turner, RMP 70, 303 (1998) • Steigman, ARNPS 57, 463 (2007) • Predicted abundances and uncertainties • Nollett/Burles, PRD 61, 123505 (2000) • Burles/Nollett/Turner, ApJ 552, L1 (2001) • Lopez/Turner, PRD 59, 103502 (1999) • Cyburt, PRD 70, 023505 (2004) • Serpico, JCAP 0412 (2004) 010 • Serebrov et al, PLB 605, 72 (2005) • Deuterium • O’Meara et al, ApJ 649, L61 (2006) Michael S Turner

  20. CMB anisotropy is a non-trivial map of density inhomogeneity to temperature fluctuations: Mapping depends upon cosmological parameters (good news!) ΩMh2 Michael S Turner

  21. γ/neutrinos Quark/Hadron All SM Particles e± pairs Relativistic Degrees of Freedom Michael S Turner

  22. Neutrino Counting • BBN (pre-LEP): Nν< 4 • Lab (LEP): Nν= 2.994 ± 0.012 • BBN: Nν< 3.2 (95%) • CMB: Nν = 4.4 ± 1.5 Michael S Turner

  23. BBN: GR Independent Quenched ReactorCarroll/Kaplinghat, PRD 65, 063507 (2002) Michael S Turner

  24. “Precision Cosmology”with SDSS + WMAP: concordance model Standard Hot Big Bang of the 1970s Flat, accelerating Universe Atoms, exotic dark matter & dark energy Consistent with inflation Precision set of cosmological parameters Ω0 = 1.005 ± 0.006 (uncurved) ΩM = 0.28 ± 0.013 ΩB = 0.045 ± 0.002 ΩΛ = 0.72 ± 0.02 H0 = 70 ± 1.3 km/s/Mpc t0 = 13.73 ± 0.12 Gyr Nν = 4.4 ± 1.5 Consistent with all data, laboratory and cosmological! Michael S Turner

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