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Gary Steigman

PROBING THE UNIVERSE AT 20 MINUTES AND 400 THOUSAND YEARS. Gary Steigman. The Ohio State University. OSU Physics Colloquium, November 21, 2006. The Universe is expanding and is filled with radiation. ~ 100 s after the Big Bang Primordial Nucleosynthesis.

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Gary Steigman

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  1. PROBING THE UNIVERSE AT 20 MINUTES AND 400 THOUSAND YEARS Gary Steigman The Ohio State University OSU Physics Colloquium, November 21, 2006

  2. The Universe is expanding and is filled with radiation

  3. ~ 100 s after the Big Bang Primordial Nucleosynthesis ~ 0.1 s after the Big Bang Neutrinos Decouple ~ 400 kyr after the Big Bang Relic Photons (CBR) are free

  4. BBN & The CBR Provide Complementary Probes Of The Early Universe Do predictions and observations of the baryon density and the expansion rate agree at 20 minutes and at 400 kyr ?

  5. Baryon Density Parameter Note : Baryons  Nucleons   nN /n ; 10   = 274Bh2 where : B  B /c and : h  H0 /100km/s/Mpc 0.7 H0-1 = 9.8 / h Gyr 14 Gyr

  6. The Early, Hot, Dense Universe Is A Cosmic Nuclear Reactor BBN “begins” at T 70 keV (when n / p 1 / 7) Coulomb barriers and the absence of free neutrons end BBN at T 30 keV tBBN 424 min.

  7. Evolution of Deuterium 10 More nucleons  less D

  8. Evolution of Helium - 4 All/most neutrons are incorporated in 4He n/p  1/7  Y  0.25 Y4He Mass Fraction 10 Y is neutron limited Y is VERY WEAKLY dependent on the nucleon abundance

  9. BBN – Predicted Primordial Abundances BBN Abundances ofD, 3He, 7Li are RATE (Density) LIMITED 7Li 7Be D, 3He, 7Li are potential BARYOMETERS

  10. Two pathways to mass - 7

  11. DEUTERIUM --- TheBaryometerOf Choice • As the Universe evolves,D is only DESTROYED  • * Anywhere, Anytime : (D/H) t  (D/H) P • * For Z << Z : (D/H) t (D/H) P (Deuterium Plateau) • (D/H) P is sensitive to the baryon density (    ) • H  and D areseen in AbsorptionBUT … • * H and D spectra are identical  H Interlopers? • * Unresolved velocity structure  Errors in N(H) ?

  12. Ly -  Absorption

  13. D/H vs. Metallicity Real variations, systematic differences, statistical uncertainties ? Deuterium Plateau ? Low – Z / High – z QSOALS

  14. D/H vs. HI Column Density D/H Correlated With N(H I) ?

  15. D/H vs. H I Column Density NEW (2006)

  16. D/H vs. H I Column Density D/H Correlated With N(H I) ?

  17. D/H vs. Metallicity For Primordial D/H adopt the mean and the dispersion around the mean 105(D/H)P= 2.65± 0.25

  18. (D/H)P+SBBN Constrains 10 (@ ~ 7%) SBBN

  19. CBR

  20. CBR Temperature Anisotropy Spectrum (T2 vs. ) Encodes The Baryon Density   Barger et al. (2003) Amplitudes of odd/even peaks depend on Bh2 Bh2 =0.018, 0.023, 0.028 CBR (WMAP) constrains Bh2 The CBR is an early - Universe Baryometer

  21. CBR Constrains 10(@ ~ 3%) CBR

  22. BBN (20 min) & CBR (380 kyr) AGREE ! BBN CBR

  23. D/H vs. Metallicity The CBR is a good Deuteronometer ! BBN + WMAP

  24. The Expansion Rate (H  Hubble Parameter) provides a probe of Non-Standard Physics • S  H / H  (/)1/2  (1 + 7N /43)1/2 for :    + N  and N  3 + N • 4He is sensitive to S while D probes 

  25. 4Heis an early– Universe Chronometer YP & yD  105 (D/H) 4.0 2.0 3.0 0.25 0.24 0.23 D&4HeIsoabundance Contours Kneller & Steigman (2004)

  26. As O/H  0, Y  0 SBBN Prediction

  27. BBN (D, 4He)  For N ≈ 2.5±0.3 YP & yD  105 (D/H) 4.0 3.0 2.0 0.25 0.24 0.23

  28. Non-Standard BBN (Example of Neff < 3) Late Decay of a Massive Particle Kawasaki,Kohri&Sugiyama & Low Reheat Temp. (TR  MeV) Neff<3  Relic Neutrinos Not Fully (Re)Populated

  29. CBR Temperature Anisotropy Spectrum Encodes the Radiation Density R(SorN)   N =1, 2.75,5, 7 Peak locations vary with N Barger et al. (2003) CBR constrains N(S) The CBR is an early - Universe Chronometer

  30. BBN (D & 4He) + CBR (WMAP) BBN & CBR Consistent ! CBR BBN Barger et al. (2003) Barger et al. (2003)

  31. Joint BBN (D & 4He) & CBR Fit But, is Li Consistent ? N < 4 N> 1 Barger et al. (2003) Barger et al. (2003)

  32. BBN and Primordial (Pop ) Lithium Li too low ? [Li]BBN12 + log(Li/H) 2.6 – 2.7 [Li]OBS 12 + log(Li/H) 2.1

  33. Even for N  3 yLi  1010 (Li/H) • Y + DH • [Li]  2.60 0.07 (vs. [Li]OBS  2.1) 4.0 3.0 2.0 4.0 Li depleted/diluted in Pop  stars ? Or, New Physics ?

  34. Baryon Density () Determinations  ?   N< 3 ?

  35. Observational Uncertainties Or New Physics? X ? 2σ ? 2σ  ? N< 3 ?

  36. N(S) Determinations BBN is a better Chronometer than the CBR V. Simha

  37. SUMMARY • SBBN (N = 3) D/H & CBR  • BBN (D & 4He) & CBR agree for : • 10 =6.1(Bh2= 0.022) & N = 2.5 (?) * 95% Ranges : 1.9  N  3.1 5.5  10  6.6 (B≈0.04 – 0.05)

  38. SUCCESS BBN and the CBR Agree ! But, what’s up with Lithium ? CHALLENGE (The Theorist’s Mantra) More & Better Data Are Needed !

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