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BIG BANG NUCLEOSYNTHESIS CONFRONTS COSMOLOGY AND PARTICLE PHYSICS

BIG BANG NUCLEOSYNTHESIS CONFRONTS COSMOLOGY AND PARTICLE PHYSICS. Gary Steigman Departments of Physics and Astronomy Center for Cosmology and Astro-Particle Physics Ohio State University. Horiba International Conference : COSMO/CosPA 2010

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BIG BANG NUCLEOSYNTHESIS CONFRONTS COSMOLOGY AND PARTICLE PHYSICS

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  1. BIG BANG NUCLEOSYNTHESIS CONFRONTS COSMOLOGY AND PARTICLE PHYSICS Gary Steigman Departments of Physics and Astronomy Center for Cosmology and Astro-Particle Physics Ohio State University Horiba International Conference : COSMO/CosPA 2010 Tokyo, Japan, September 27 – October 1, 2010

  2. Baryon Density Parameter : B Note : Baryons  Nucleons B  nN /n ; 10  B= 274Bh2 (ηB not predicted (yet) by fundamental theory) Hubble Parameter : H = H(z) In The Early Universe: H2 α Gρ

  3. Expansion Rate Parameter : S  H/H S ≠ 1 is a Probe of Non - Standard Physics • Pre - e± Ann. :S2= GR /GR 1 + 7N /43 Where : N (R-R)/and N3 + N IfR = R , GBBN/ G0 = S2 = 1+0.163N • 4He is sensitive to S (ΔN); D probes B • Post - e± Ann. : R /R 1 + 0.134N Where : Neff3.046 + N

  4. “Standard” Big Bang Nucleosynthesis (SBBN) For An Expanding Universe Described By General Relativity, With S = 1 (ΔN = 0) The Relic Abundances of D, 3He, 4He, 7Li depend on only one parameter : ηB Big Bang Nucleosynthesis (BBN) : S ≠ 1 Relic Abundances depend on ηBandS(ΔN)

  5. BBN(~3Minutes) , The CMB(~400kyr) , LSS (~ 10 Gyr) Provide Complementary Probes Of The Early Evolution Of The Universe * Do the BBN - predicted abundances agree with observationally - inferred primordial abundances ? • Do the BBN and CMB values of B agree ? • Do the BBN and CMB values of ΔN agree ? • Is ΔN BBN = ΔN CMB = 0 ?

  6. SBBN – Predicted Primordial Abundances 4He Mass Fraction Mostly H &4He BBN Abundances ofD, 3He, 7Li are RATE (DENSITY) LIMITED 7Li 7Be D, 3He, 7Li are potential BARYOMETERS

  7. Post – BBN Evolution of the Relic Abundances • As gas cycles through stars,D is only DESTROYED • As gas cycles through stars,3He is DESTROYED, • PRODUCED and, some prestellar 3HeSURVIVES • Stars burn H to 4He (and produce heavy elements) •  4HeINCREASES (along with CNO …) • Cosmic Rays and SOME Stars PRODUCE7Li BUT, • 7Li is DESTROYED in most stars

  8. DEUTERIUM Is The Baryometer Of Choice • The Post – BBN Evolution of D is Simple : • 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 (  B − ) • H  and D areobserved in Absorption in High – z, • Low – Z, QSO Absorption Line Systems (QSOALS)

  9. log (D/H) vs. Oxygen Abundance Observations of Deuterium In 7 High - Redshift, Low - Metallicity QSOALS (Pettini et al. 2008) Where is the D – Plateau ?

  10. log (D/H) vs. Oxygen Abundance log(105(D/H)P) = 0.45 ± 0.03  10(SBBN) = 5.80 ± 0.27

  11. 3He Observed In Galactic H Regions 3He/H vs. O/H Stellar Produced (?) (3He/H)P for B = B(SBBN + D) 3He Is Consistent With SBBN

  12. Y vs. O / H Izotov & Thuan 2010 4He Observed in Low – Z Extragalactic H  Regions

  13. Y vs. O / H YP(IT10) = 0.2565 ± 0.0010 ± 0.0050 YP = 0.2565 ± 0.0060

  14. For SBBN (ΔN= 0) With • 5 + log(D/H)P = 0.45 ± 0.03  • YP = 0.2482 ± 0.0007 • YP(OBS) − YP(SBBN) = 0.0083 ± 0.0060 • YP(OBS) = YP(SBBN) @ ~ 1.4 σ

  15. But ! Lithium – 7 Is A Problem Li/H vs. Fe/H [Li] ≡ 12 + log(Li/H) SBBN Asplund et al. 2006 Boesgaard et al. 2005 Aoki et al. 2009 Lind et al. 2009 Where is the Lithium Plateau ?

  16. SBBN Predictions Agree With Observations Of D, 3He, 4He, But NOT With 7Li For BBN (with η10 & ΔN (S) as free parameters) BBN Abundances Are Functions of η10 & S (ΔN)

  17. Isoabundance Contours for 105(D/H)P & YP YP &yD  105 (D/H) 0.26 4.0 3.0 2.0 0.25 0.24

  18. Isoabundance Contours for 105(D/H)P & YP YP&yD  105 (D/H) 0.26 4.0 3.0 2.0 0.25 0.24

  19. For BBN (ΔN≠0) With 5 + log(D/H)P = 0.45 ± 0.03 & YP = 0.2565 ± 0.0060  η10 = 6.07 ± 0.33 & ΔN = 0.62 ± 0.46 ΔN = 0 @ ~ 1.3 σ GBBN /G0 = 1.10 ± 0.07 But, what about Lithium ?

  20. Lithium Isoabundance Contours [Li]P = 12 + log(Li/H)) 2.6 2.7 2.8

  21. Even for N 3 , [Li]P > 2.6 [Li]P = 12 + log(Li/H)) 2.6 2.7 2.8

  22. Lithium – 7 Is STILL A Problem [Li] ≡ 12 + log(Li/H) BBN [Li]OBS too low by ~ 0.5 – 0.6 dex

  23. CMB Temperature Anisotropy Spectrum Depends On The Baryon Density For ΔN = 0, is B(CMB) = B(SBBN) ? For ΔN ≠ 0, is B(CMB) = B(BBN) ?

  24. Likelihood Distributions For η10 SBBN & CMB Agree Within ~ 1.3 σ SBBN CMB

  25. Likelihood Distributions For η10 BBN & CMB Agree At < 1 σ BBN CMB

  26. At BBN, With η10 & ΔN As Free Parameters ΔN(BBN) = 0.62 ± 0.46  ΔN(BBN)= 0 @ ~ 1.3 σ At REC, With CMB (WMAP 7 Year Data) + LSS ΔN(REC) = 1.30 ± 0.87  ΔN(REC)= 0 @ ~ 1.5 σ

  27. Likelihood Distributions For N BBN & CMB Agree At < 1 σ BBN CMB

  28. Likelihood Distributions For N N = 4 (?) N = 3 N(BBN) depends on YP BBN CMB

  29. Chronology of Primordial Helium Abundance Determinations

  30. Chronology Of The BBN – Inferred Values Of N CMB

  31. CONCLUSION # 1 SBBNIS Consistent With D, 3He, 4He And Agrees With The CMB + LSS + H0 (But , Lithium Is A Problem !) • Li depleted / diluted in Pop  Stars ? • Post – BBN Decay of Massive Particles ? • Annihilation of Dark Matter Relics ?

  32. CONCLUSION # 2 Non - standard BBN (ΔN ≠ 0, S ≠ 1) IS Consistent With D, 3He, & 4He And With The CMB + LSS (But, not7Li) * BBN + CMB Combined Can Constrain Non-standard Cosmology & Particle Physics

  33. Comparing BBN And The CMB Entropy (CMB Photon) Conservation * In a comoving volume, N = NB / ηB * For conserved baryons, NB = constant * Comparing ηB at BBN and at Recombination N (REC)/ N (SBBN) = 0.94 ± 0.05 N(REC)/ N(BBN) = 0.98 ± 0.06

  34. “Extra” Radiation Density ? Example : Late decay of a massive particle Pre - e± Ann. : (ρR/ ρ R)BBN = 1 + 0.163 N Post - e± Ann. : (ρR/ ρ R)REC = 1 + 0.134 N In the absence of the creation of new radiation (via decay ?), (ρR/ ρ R)BBN = (ρR/ ρ R)REC Comparing ΔNat BBN and at Recombination  (ρR/ ρ R)REC − (ρR/ ρ R)BBN = 0.07 ± 0.14

  35. CONCLUSIONS For ΔN≈ 0, BBN (D, 3He, 4He) Agrees With The CMB + LSS (But , Lithium Is A Problem !) BBN + CMB + LSS Can Constrain Cosmology & Particle Physics

  36. CHALLENGES • Why is the spread in D abundances so large ? • Why is 3He/H uncorrelated with O/H and/or R ? • What (how big) are the systematic errors in YP ? • Are there observing strategies to reduce them ? • What is the primordial abundance of 7Li (6Li) ? More data is needed !

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