Neutrino and Dark Radiation properties in light of recent ...
Transcript of Neutrino and Dark Radiation properties in light of recent ...
Neutrino and Dark Radiation properties in
light of recent CMB observations
MA, Elena Giusarma, Olga Mena and Alessandro Melchiorri, arXiv:1303.0134 (2013)
ITP Cosmology Seminars, Heidelberg, 8 May 2013
Maria Archidiacono
MA, Erminia Calabrese and Alessandro Melchiorri, PRD 84 (2011) 1230008 Smith, MA, Cooray, De Bernardis, Melchiorri, Smith, PRD 85 (2012) 123521
Outline
• Cosmic Neutrino Background
• Massive Neutrinos and Dark Radiation effects on CMB and mpk
• State of art of the cosmological constraints on neutrino physics
• Adding external data sets and extending the cosmological scenarios
• Discrepancies and degeneracies
• Planck results
• Conclusions
Before Planck!
Weak interactions in the primordial plasma:
where
When we have the neutrino decoupling
If the decoupling was istantaneous, we get:
So nowaday
Cosmological standard value
(non-istantaneous decoupling)
enep cn
H
MeVTk decB 1
3/14/11/ TT
KT 95.1
Cosmic Neutrino Background
2me
ee
ee
t
T
t
046.3effN
effrad N
3/4
11
4
8
71
Probing the Neutrino mass with cosmological data
Early ISW
eV
mNh
93
2
Equivalence
f
cdm a 5
31
WMAP-9
Assuming 3 degenerate neutrinos Hinshaw et al (2013)
.).%95(3.1 lceVm
WMAP-7+SDSS+H0
Hannestad et al (2010)
Free-streaming:
.).%95(44.0 lceVm
H
vthFS
3
22
skmm
eVzvth /
11150
Model dependence: Curvature
m <0.45 eV (95%cl) <0.95 eV (95%cl)
k 10^3 0 7.52±7.74
The degeneracy considerably increases the uncertainty in the sum of neutrino masses.
WMAP-7 + ACT + SPT + BAO + H0
Smith, MA et al., PRD (2012)
Pre-Planck state of art for Neutrino mass
eVm )11.032.0(
SPT+WMAP7+H0+BAO+SPTcl: Hou et al. 2012
.).%95(39.0 lceVm
ACT+WMAP7+H0+BAO:
Sievers et al. 2013
The effective number of relativistic degrees of freedom
The total amount of relativistic degrees of freedom in the Universe is therefore parametrized in the following way:
2
3/4
2
11
4
8
71 hNh effR
A value of Neff > 3.046 is equivalent to the presence of a new «dark radiation» component :
4443
2
0 aaaaH
H DRM
Changing the Neutrino effective number essentially changes the expansion rate H at recombination. So it changes the size of the sound horizon at recombination:
and the damping at recombination:
Moreover a larger neutrino number increases the early ISW as the neutrino mass .
**
0 20/
as
t
ssH
da
a
cadtcr
Hou et al (2011)
Probing the Neutrino number with CMB data
*
0 2
2
3
22
)1(6
)1(15
6
)2(a
eT
dR
RR
Hna
dar
fixedd
Cosmological parameters degeneracies
Clusters and Ly-alpha surveys move to Neff = 3
Extra Dark Radiation 12.8 Gyrs
MA, Calabrese, Melchiorri, PRD (2011)
Pre-Planck state of art for Dark Radiation
WMAP-7+SPT
WMAP-7+SPT+BAO+H0 Hou et al. (2013)
48.062.3 effN
55.078.2 effNWMAP-7+ACT
WMAP-7+ACT+BAO+H0 Sievers et al. (2013)
35.071.3 effN
39.051.3 effN
W9+SPT W9+SPT +HST
W9+SPT +BAO
W9+SPT +BAO +HST
W9+SPT +SNLS
W9+SPT +SNLS +BAO
m (eV) 1.14±0.41 <0.50 0.46±0.18 0.33±0.17 <0.80 0.40±0.18
W9+ACT W9+ACT +HST
W9+ACT +BAO
W9+ACT +BAO +HST
W9+ACT +SNLS
W9+ACT +SNLS +BAO
m (eV) <0.89 <0.34 <0.53 <0.44 <0.49 <0.54
•CMB •CMB+HST •CMB+BAO •CMB+BAO+HST •CMB+SNLS •CMB+SNLS+BAO
MA, Giusarma, Melchiorri, Mena (2013)
CDM + 3 massive neutrinos
SPT ACT
CDM + Neff W9+SPT W9+SPT
+HST W9+SPT +BAO
W9+SPT +BAO +HST
W9+SPT +SNLS
W9+SPT +SNLS +BAO
Neff 3.93±0.68 3.59±0.39 3.50±0.59 3.83±0.41 4.93±0.69 3.55±0.63
W9+ACT W9+ACT +HST
W9+ACT +BAO
W9+ACT +BAO +HST
W9+ACT +SNLS
W9+ACT +SNLS +BAO
Neff 2.74±0.47 3.12±0.38 2.77±0.49 3.43±0.36 2.77±0.49 2.83±0.47
SPT ACT
CDM + massive Neff W9+SPT W9+SPT
+HST W9+SPT +BAO
W9+SPT +BAO +HST
W9+SPT +SNLS
W9+SPT +SNLS +BAO
m (eV) 1.35±0.55 0.48±0.33 0.56±0.22 0.56±0.23 <0.91 0.50±0.21
Neff 3.66±0.61 4.08±0.54 3.76±0.67 4.21±0.46 4.04±0.68 3.87±0.68
W9+ACT W9+ACT +HST
W9+ACT +BAO
W9+ACT +BAO +HST
W9+ACT +SNLS
W9+ACT +SNLS +BAO
m (eV) <0.89 <0.34 <0.53 <0.44 <0.49 <0.54
Neff 2.64±0.51 3.20±0.38 2.63±0.48 3.44±0.37 2.75±0.44 2.78±0.46
SPT ACT
What Dark Radiation is made of? Sterile Neutrinos?
Exotic models:
• gravitational waves
• axions • decay of non-relativistic matter • Early Dark Energy
Massless neutrinos equations of perturbations:
.3,112
,5
3
15
8
5
23
,3
23
,3
2331
1,1,,
3,
2
2
2
lFllFFk
l
kFqc
kqa
a
k
q
a
akcq
hk
qkk
q
a
ac
a
a
lll
vis
eff
eff
The effective sound speed
The viscosity parameter 2
2
vis
eff
c
c
Effective sound speed and viscosity speed
3/122 viseff cc
0,3/1 22 viseff cc
1,3/1 22 viseff cc
3/122 viseff cc
If Dark Radiation is made of free-streaming
particles,
WMAP-7 ACT
3/1,2.0 22 viseff cc
3/1,7.0 22 viseff cc
Hu (1998), Smith et al. (2012)
CDM + DNeff + c2eff + c2
vis + 3 massive (0.3 eV) neutrinos with standard perturbations’ parameters
60.031.1 D effNW9+SPT
W9+SPT+HST
W9+ACT
W9+ACT+HST
32.038.0 D effN
39.092.0 D effN
41.062.0 D effN
W9+SPT+BAO+HST
W9+ACT+BAO+HST
07.015.02 visc
13.025.02 visc
W9+SPT/ACT+BAO+HST W9+SPT/ACT+BAO+HST
CDM + m + DNeff + c2eff + c2
vis
W9+SPT+BAO+HST
W9+ACT+BAO+HST
07.013.02 visc
11.025.02 visc
W9+SPT+BAO+HST
W9+ACT+BAO+HST
50.035.1 D effN
40.074.0 D effN
The evidence for neutrino mass still remains if SPT is combined with BAO
SPT ACT
To sum up …
W9+SPT W9+SPT+ external data
W9+ACT W9+ACT+external data
Standard Model Neutrino Mass
Detection Detection (BAO, BAO+HST, BAO+SN)
No detection
No detection
Extended Model Neutrino Mass
No detection
No detectionw:detect. with SN
No detection
No detection
Standard Model Dark Radiation
Evidence Evidence No evidence
Evidence only with BAO+HST
Extended Model Dark Radiation
Evidence Non-standard c2
vis
Evidence Non-standard c2
vis
No evidence
Evidence only with BAO+HST
Planck
.).%68(//)2.13.67(0 lcMpcskmH
ESA and the Planck Collaboration
“A simple but challenging Universe”
MpcskmH //4.28.730 HST, Riess et al (2011)
Planck and Neutrino mass
CDM + m
.).%95(66.0 lceVm
CDM + m + Alens
.).%95(08.1 lceVm
Planck+WMAP9polarization +highl(SPT+ACT)
ESA and the Planck Collaboration
Planck and Dark Radiation
.).%95(36.3 68.0
64.0 lcNeff
Planck+WMAP9polarization +highl(SPT+ACT)
Planck+WMAP9polarization +highl(SPT+ACT)+HST
.).%95(62.3 50.0
48.0 lcNeff
ESA and the Planck Collaboration
Planck and Sterile Neutrinos
Planck+WMAP9polarization +highl(SPT+ACT)
Planck+WMAP9polarization +highl(SPT+ACT) + BAO
.).%95(60.0 lceVm
.).%95(29.3 67.0
64.0 lcNeff
.).%95(32.3 54.0
52.0 lcNeff
.).%95(28.0 lceVm
ESA and the Planck Collaboration
Conclusions
• Detection of a non zero neutrino mass by SPT, tight upper bound on the absolute neutrino mass scale with Planck combined with high-l; • Evidence for extra dark radiation with SPT, standard Neff with ACT, evidence for extra dark radiation with Planck only if combined with HST. • The extra dark radiation seen by SPT can be related to exotic models (cvis
2 < 0.33 @95%cl) • Massive sterile neutrinos of Short BaseLine Oscillation experiments are not excluded, but a partial thermalisation must be invoked.