Introductionto Cosmology

Lecture 8

Cyburt+ 2015

Nollett & Burles 2000

The lightest elements are created

FIG. 1. Primordial abundances of the light nuclides as a function of cosmic baryon content, as

predicted by SBBN (“Schramm plot”). These results assume Nν = 3 and the current measurement

of the neutron lifetime τn = 880.3 ± 1.1 s. Curve widths show 1− σ errors.

D

H= 2.579×10−5

!

1010η

6.10

"−1.60#Nν

3.0

$0.395!

GN

GN,0

"0.95#τn

880.3s

$0.41

× [p(n, γ)d]−0.19 [d(d, n)3He]−0.53 [d(d, p)t]−0.47

× [d(p, γ)3He]−0.31

[3He(n, p)t]0.023

[3He(d, p)4He]−0.012

(14)

3He

H= 9.996×10−6

!

1010η

6.10

"−0.59#Nν

3.0

$0.14!

GN

GN,0

"0.34#τn

880.3s

$0.15

× [p(n, γ)d]0.088 [d(d, n)3He]0.21 [d(d, p)t]−0.27

× [d(p, γ)3He]0.38 [3He(n, p)t]−0.17 [3He(d, p)4He]−0.76 [t(d, n)4He]−0.009 (15)

7Li

H= 4.648×10−10

!

1010η

6.10

"2.11#Nν

3.0

$−0.284!

GN

GN,0

"−0.73#τn

880.3s

$0.43

20

Cyburt+ 2015

L Kewley

Aver+ 2015

BBN theory confronts observations 2015

Cooke 14

Sbordone 10

Aver 15

Quasar Absorption Line Spectroscopy

Energy Levels

15 *5-&"6+3) 7+8'+&.89)

Energy Levels

15 *5-&"6+3) 7+8'+&.89)

blue-shift of 82 km/s

Precision Measures of (D/H) [Cooke et al. 2017]

(D/H)DLA = (2.53± 0.03)⇥ 10�5

Precision Measures of (D/H) [Cooke et al. 2017]

(Random + Systematic Error)

100⌦b,0h2(BBN) = 2.235± 0.05

BBN theory confronts observations 2015

Cooke 14

Sbordone 10

Aver 15

Sbordone+ 2010

BBN theory confronts observations 2015

Cooke 14

Sbordone 10

Aver 15

N⌫ = 4

N⌫ = 3

N⌫ = 2

Cyburt+ 2015

Cooke+ 2014