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BBN, NEUTRINOS, AND THE CBR

BBN, NEUTRINOS, AND THE CBR. Gary Steigman (with J. P. Kneller & V. Simha) Center for Cosmology and Astro-Particle Physics Ohio State University. PPC 2007, TAMU, May 14 – 18, 2007. ~ 100 s after the Big Bang Primordial Nucleosynthesis. ~ 0.1 s after the Big Bang

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BBN, NEUTRINOS, AND THE CBR

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  1. BBN, NEUTRINOS, AND THE CBR Gary Steigman (with J. P. Kneller & V. Simha) Center for Cosmology and Astro-Particle Physics Ohio State University PPC 2007, TAMU, May 14 – 18, 2007

  2. ~ 100 s after the Big Bang Primordial Nucleosynthesis ~ 0.1 s after the Big Bang Neutrinos Decouple ~ 380 kyr after the Big Bang Relic Photons (CBR) are free

  3. BBN(~20Minutes)& The CBR(~400kyr) Provide Complementary Probes Of The Early Evolution Of The Universe * Neutrinos Play Important Roles At Both Epochs Do predictions and observations of the baryon density (10(nB/nγ)0=274 Bh2) and expansion rate (H) of the Universe agree at these different epochs?

  4. The Early, Hot, Dense Universe Is A Cosmic Nuclear Reactor As the Universe expands and cools, 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.

  5. BBN – Predicted Primordial Abundances 4He Mass Fraction BBN Abundances ofD, 3He, 7Li are RATE (Density) LIMITED 7Li 7Be D, 3He, 7Li are potential BARYOMETERS

  6. 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 Absorption,BUT … • * H and D spectra are identical  H Interlopers? • * Unresolved velocity structure  Errors in N(H) ?

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

  8. D/H vs. Metallicity For Primordial D/H adopt the mean For the error adopt the dispersion around the mean 105(D/H)P= 2.68± 0.27

  9. D + SBBN10 =6.0± 0.4 SBBN

  10. CBR

  11. CBR Temperature Anisotropy Spectrum (T2 vs. ) Depends On The Baryon Density  10=4.5,6.1,7.5 CBR constrains 10 V. Simha & G.S. The CBR is an early - Universe Baryometer

  12. CBR10 =6.1±0.2 CBR V. Simha & G.S. (2007)

  13. CBR & SBBN (D) Agree ! SBBN

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

  15. Do SBBN Predictions of D and 4He Agree ? As O/H  0, Y  0 SBBN Prediction

  16. Likelihoods (SBBN) from D and 4He AGREE ?

  17. D & 4He Isoabundance Contours YP & yD  105 (D/H) 4.0 2.0 3.0 0.25 0.24 0.23 Kneller & Steigman (2004)

  18. BBN (D, 4He)  For N ≈ 2.4 ± 0.4 YP & yD  105 (D/H) 4.0 3.0 2.0 0.25 0.24 0.23 D&4HeIsoabundance Contours Kneller & Steigman (2004)

  19. NSBBN (D & 4He)  10 = 5.7 ±0.4 NSBBN

  20. BBN (20 min) & CBR (380 kyr) AGREE on 10

  21. NSBBN (D & 4He)N =2.4 ± 0.4 NSBBN

  22. CBR Temperature Anisotropy Spectrum Depends on the Radiation Density R(SorN)   N =1, 3,5 CBR constrainsN(S) V. Simha & G.S. The CBR is an early - Universe Chronometer

  23. N =2.3 (1.2 ≤ N≤ 4.4 @ 68%) CBR

  24. BBN (20 min) & CBR (380 kyr) AGREE on N CBR BBN

  25. BBN (D & 4He) BBN Constrains N N < 4 N> 1 V. Simha & G.S.

  26. CBR CBR Constrains10 V. Simha & G.S.

  27. BBN (D & 4He) & CBR AGREE ! V. Simha & G.S.

  28. BBN and Primordial (Pop ) Lithium Li too low ? [Li]12 + log(Li/H) 2.6 – 2.7 Lithium ( “Spite” ) Plateau (?) [Li]  12 + log(Li/H) 2.1

  29. Even for N  3 yLi  1010 (Li/H) • Y + DH • Li H  4.0  0.7 x 1010 • log (Li) 2.6 0.1 (vs. log (Li)obs  2.2) 4.0 3.0 2.0 4.0 0.25 0.24 0.23 Li depleted/diluted in Pop  stars ?

  30. Summary : Baryon Density Determinations D & 3He agree with the CBR Depleted ? N< 3 ?

  31. Summary : N Determinations 95% Ranges

  32. SUCCESS BBN (D & 4He) and the CBR Agree ! (Lithium ?) CHALLENGE (The Theorist’s Mantra) More & Better Data Are Needed !

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