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

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

BBN (~ 20 Minutes) & The CBR (~ 400 kyr) Provide Complementary Probes Of The Early Evolution Of The Universe Do predictions and observations of the baryon density (  10    (n B /n γ ) 0 = 274  B h 2 ) and expansion rate ( H ) of the Universe agree at these different epochs? * Neutrinos Play Important Roles At Both Epochs

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  t BBN  4  24 min. The Early, Hot, Dense Universe Is A Cosmic Nuclear Reactor

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

DEUTERIUM --- The Baryometer Of 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) H  and D  are seen in Absorption, BUT … * H  and D  spectra are identical  H  Interlopers? * Unresolved velocity structure  Errors in N(H  ) ? (D/H) P is sensitive to the baryon density (     )

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

10 5 (D/H) P = 2.68 ± 0.27 For Primordial D/H adopt the mean For the error adopt the dispersion around the mean D/H vs. Metallicity

D + SBBN   10 = 6.0 ± 0.4 SBBN

CBR

CBR Temperature Anisotropy Spectrum (  T 2 vs.  ) Depends On The Baryon Density The CBR is an early - Universe Baryometer    10 = 4.5, 6.1, 7.5 CBR constrains  10 V. Simha & G.S.

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

SBBN CBR & SBBN (D) Agree !

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

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

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

Y P & y D  10 5 (D/H) D & 4 He Isoabundance Contours Kneller & Steigman (2004)

BBN (D, 4 He)  For N ≈ 2.4 ± 0.4 Y P & y D  10 5 (D/H) D & 4 He Isoabundance Contours Kneller & Steigman (2004)

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

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

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

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

CBR N = 2.3 (1.2 ≤ N ≤ 68 %)

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

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

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

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

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

y Li  (Li/H) 4.0 Even for N  3 Y + D  H  Li  H  4.0  0.7 x 10  10  log  (Li)  2.6  0.1 (vs. log  (Li) obs  2.2) Li depleted / diluted in Pop  stars ?

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

Summary : N Determinations  95% Ranges

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