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EARLY UNIVERSE CONSTRAINTS ON NEUTRINOS AND BARYONS

EARLY UNIVERSE CONSTRAINTS ON NEUTRINOS AND BARYONS. Gary Steigman Departments of Physics and Astronomy Center for Cosmology and Astro-Particle Physics Ohio State University. Neutrino Frontiers Workshop University of Minnesota, October 23 – 26, 2008.

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EARLY UNIVERSE CONSTRAINTS ON NEUTRINOS AND BARYONS

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  1. EARLY UNIVERSE CONSTRAINTS ON NEUTRINOS AND BARYONS Gary Steigman Departments of Physics and Astronomy Center for Cosmology and Astro-Particle Physics Ohio State University Neutrino Frontiers Workshop University of Minnesota, October 23 – 26, 2008

  2. Baryon Density Parameters Note : Baryons  Nucleons B  nN /n ; 10  B= 274Bh2 BBN And The CMB + LSS Probe The Early – Universe Baryon Density (At Widely Separated Epochs)

  3. BBN & CMB + LSS Provide Complementary Probes Of The Early Evolution Of The Universe Do predictions and observations of the baryon density (B) andthe expansion rate (H) of the Universe agreeat these different epochs ? G. S., Ann. Rev. Nucl. Part. Sci., 57 (2007) 463 V. Simha & G. S., JCAP, 06 (2008) 016 V. Simha & G. S., JCAP, 10 (2008) 001

  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 terminate BBN at T 30 keV tBBN 424 min.

  5. BBN – 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

  6. DEUTERIUM --- TheBaryometerOf Choice • (D/H) P is sensitive to the baryon density (    ) • 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) • H  and D areseen in Absorption (QSOALS),BUT … • * H and D spectra are identical  H Interlopers? • * Unresolved velocity structure  Errors in N(H) ?

  7. Observations of Deuterium In 7 High-Redshift, Low-Metallicity QSO Absorption Line Systems 105(D/H)P = 2.7 ± 0.2 (Weighted Mean of D/H) (Weighted mean of log (D/H) 105(D/H)P = 2.8 ± 0.2)

  8. (D/H)obs + SBBNpred10 =6.0± 0.3 SBBN V. Simha & G. S.

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

  10. CMB10 =6.1±0.2 10Likelihood CMB V. Simha & G. S.

  11. SBBN (~ 20 min) & CMB (~ 380 kyr) AGREE 10Likelihoods CMB SBBN V. Simha & G. S.

  12. 4He Observed In Extragalactic H  Regions As O/H  0, Y  0 SBBN Prediction: YP = 0.249 K. Olive YP = 0.240 ± 0.006 ( Or, YP < 0.255 @ 2 σ )

  13. YP depends VERY WEAKLY on the nucleon abundance Almost all neutrons are incorporated in 4He n/p  1/7  YP 0.25 P YP4He Mass Fraction 10 YP DOES depend on the competition between Γwk & H

  14. SBBN 10Likelihoods from D and 4He AGREE ? to be continued …

  15. The Expansion Rate (H  Hubble Parameter) Is A Probe Of Non-Standard Physics • S2  (H/ H)2= G/G  1 + 7N /43 • * S can be parameterized by N N (G-G) / G and N  3 + N NOTE : G/ G = S2 1 + 7N / 43 • 4He is sensitive to S (N) ; D probes B

  16. Isoabundance contours for (D/H)P and YP YP & yD  105 (D/H) 4.0 3.0 2.0 0.25 0.24 0.23 Kneller & Steigman (2004)

  17. Nvs.10FromBBN(D & 4He) ( YP < 0.255 @ 2 σ ) BBN Constrains N N < 4 N> 1 V. Simha & G. S.

  18. But ! Lithium – 7 Is A Problem [Li] ≡ 12 + log(Li/H) [Li]SBBN 2.6 – 2.7 [Li]OBS 2.1 Li too low ! Recent results of Cyburt, Fields, & Olive worsens the discrepancy by ~ 0.1 dex

  19. Even for N  3 Y + DH LiH 4.0  0.7 x 1010 yLi  1010 (Li/H) 4.0 3.0 2.0 0.25 4.0 0.24 0.23 Li depleted/diluted in Pop  stars ? Kneller & Steigman (2004)

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

  21. N Is Degenerate With mh2 The degeneracy can be broken - partially - by H0 (HST) and LSS 1 + zeq =m / R 1 + zeq≈ 3200 V. Simha & G. S.

  22. CMB + LSS + HST Prior on H0 Nvs.10 CMB + LSS Constrain 10 V. Simha & G. S.

  23. BBN (D & 4He) & CMB + LSS + HST AGREE ! N vs. 10 CMB + LSS BBN V. Simha & G. S.

  24. Several consequences of the good agreement between BBN and CMB + LSS Entropy Conservation : N (CMB) / N (BBN) = 0.92 ± 0.07 Modified Radiation Density (late decay of massive particle) ρRCMB / ρRBBN = 1.07 +0.16 -0.13 Variation in the Gravitational Constant ? GBBN / G0 = 0.91 ± 0.07 ; GCMB / G0 = 0.99 ± 0.12

  25. BBN + CMB + LSS Combined Fit N vs. 10 ( YP < 0.255 @ 2 σ ) N = 2.5 ± 0.4 10= 6.1 ± 0.1 V. Simha & G.S.

  26. Alternative to N  3 (S  1) for BBN eDegeneracy (Non – Zero Lepton Number) Fore=e/kT  0(moreethan anti-e) n/pexp(m/kTe)n/pYP YP probes Lepton Asymmetry The CMB is insensitive toe for small |e|

  27. eDegeneracy (Non – Zero Lepton Number) Isoabundance contours for (D/H)P and YP YP & yD  105 (D/H) For N=3 : e=0.0350.026 2.0 4.0 3.0 0.23 0.24 & 10 = 5.9  0.4  0.25 (V. Simha & G. S.)

  28. BBN Constraints (D & 4He) On eFor N = 3 e = 0.035 ± 0.026 10= 5.9 ± 0.3 V. Simha & G.S.

  29. Even With Non-Zero eDegeneracy, The Li Problem Persists yLi  1010 (Li/H) 4.0 2.0 4.0 3.0 [Li] = 2.6  0.7 Still ! 0.23 0.24 [Li] = 2.7  0.7 with CFO 2008 results 0.25 Li depleted/diluted in Pop  stars ?

  30. N&eBOTHFREE, BBN + CMB/LSS Consistent with e = 0 & N= 3 N = 3.3 ± 0.7 e = 0.056 ± 0.046 V. Simha & G.S.

  31. CONCLUSIONS BBN (D, 3He, 4He) Agrees With The CMB + LSS (For N≈ 3 & e≈0) BBN + CMB + LSS Combined Can Constrain Non-Standard Cosmology & Particle Physics

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