MASSIVE NEUTRINOS AND COSMOLOGY
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Transcript of MASSIVE NEUTRINOS AND COSMOLOGY
04/22/23
MASSIVE NEUTRINOS AND COSMOLOGY
Sergio Pastor (IFIC)
ν
CuTAPP 2005,
Ringberg Castle
Current bounds and future sensitivities
Effect of neutrino mass on cosmological observables
Outline
Neutrinos as DM
The Cosmic Neutrino Background
• Number density
• Energy density
flavor per
cm )( 112
present at3- 3
23
3
11
3(6
11
3
2 CMBγννν Tπ
)ζn)(p,Tf
π)(
pdn
nm
T
)(p,Tfπ)(
pdmp
i
ii
CMB
νν
43/42
3
322
11
4
120
7
2
Massless
Massive mν>>T
Neutrinos decoupled at T~MeV, keeping a spectrum as that of a relativistic species 1e
1T)(p,f p/T
04/22/23
Relic neutrinos influence several cosmological epochs
T < eVT ~ MeV
Formation of Large Scale Structures
LSS
Cosmic Microwave Background
CMB
Primordial
Nucleosynthesis
BBN
No flavor sensitivity Neff & mννevs νμ,τ Neff
Non-instantaneous ν decoupling (including oscillations)
3.045N eff T.Pinto et al, in preparation
Neutrinos as Dark Matter
• Neutrinos are natural DM candidates
• They stream freely until non-relativistic (collisionless phase mixing) Neutrinos are HOT Dark Matter
• First structures to be formed when Universe became matter -dominated
• Ruled out by structure formation CDM
MpceV 30
m 41
-1
ν
Neutrino Free Streaming
b, cdm
eV 46 m 1 Ω eV 93.2
mhΩ
iiν
ii
2ν
Neutrinos as Dark Matter
• Neutrinos are natural DM candidates
• They stream freely until non-relativistic (collisionless phase mixing) Neutrinos are HOT Dark Matter
• First structures to be formed when Universe became matter -dominated
• HDM ruled out by structure formation CDM
eV 46 m 1 Ω eV 93.2
mhΩ
iiν
ii
2ν
MpceV 30
m 41
-1
ν
Neutrinos as Hot Dark Matter
• Effect of Massive Neutrinos: suppression of Power at small scales
Massive Neutrinos can still be subdominant DM: limits on mν from Structure Formation (combined with other cosmological data)
CMB DATA: INCREASING PRECISION
Multipole Expansion
Angular Power SpectrumMap of CMBR temperature
Fluctuations
T
T-),T(),Δ(
Galaxy Redshift Surveys
SDSS
2dFGRS
~ 1300 M
pc
Power Spectrum of density fluctuations
Galaxy Surveys
CMB experiments
SDSS
Field of density Fluctuations
)(
)(x
x
Matter power spectrum is the Fourier transform of the
two-point correlation function
Power spectrum of density fluctuations
Bias b2(k)=Pg(k)/Pm(k)
Non-linearity
2dFGRS
kmax
SDSS
Neutrinos as Hot Dark Matter
W. Hu
• Effect of Massive Neutrinos: suppression of Power at small scales
Massive Neutrinos can still be subdominant DM: limits on mν from Structure Formation (combined with other cosmological data)
Effect of massive neutrinos on the CMB and Matter Power
Spectra
Max Tegmark
www.hep.upenn.edu/~max/
Cosmological bounds on neutrino mass(es)
A unique cosmological bound on mν DOES NOT exist !Different analyses have found upper bounds on neutrino masses, since they depend on
• The assumed cosmological model: number of parameters (problem of parameter degeneracies)
• The combination of cosmological data used
Cosmological Parameters: example
SDSS Coll, PRD 69 (2004) 103501
Cosmological Data
• CMB Temperature: WMAP plus data from other experiments at large multipoles (CBI, ACBAR, VSA…)
• CMB Polarization: WMAP
• Large Scale Structure:
* Galaxy Clustering (2dF,SDSS)
* Bias (Galaxy, …): Amplitude of the Matter P(k) (SDSS,σ8)
* Lyman-α forest: independent measurement of power on small scales
• Priors on parameters from other data: SNIa (Ωm), HST (h), …
3 degenerate massive neutrinos Σmν = 3m0
Neutrino masses in 3-neutrino schemes
eV
From present evidences of atmospheric and solar neutrino oscillations
atmatm
solar
solar
eV 0.009 m
eV 0.05m
2sun
2atm
eV
m0
Absolute mass scale searches
Cosmology < 0.42-2.0 eV
Neutrinoless double beta decay
< 0.3-1.6 eVi
ieiee mUm 2
Tritium decay < 2.3 eV
i
im~
2/1
22
iiei mUm
e
Cosmological bounds on neutrino mass since 2003
390280640 . . .
Bound on Σmν (eV) at 95% CL
Data used
Ichikawa, Fukugita & KawasakiPRD 71 (2005) 043001
2.0 WMAP
SDSS Coll.PRD 69 (2004) 103501
1.7 WMAP, SDSS
HannestadJCAP 0305 (2003) 004
1.01 WMAP, other CMB, 2dF, HST
Crotty, Lesgourgues & SPPRD 69 (2004) 123007
1.0 [0.6] WMAP, other CMB, 2dF, SDSS [HST,SN]
Barger. Marfatia & TregrePLB 595 (2004) 55
0.75 WMAP, other CMB, 2dF, SDSS, HST
WMAP Coll.ApJ Suppl 148 (2003) 175
0.7
WMAP, other CMB,2dF (bias,galaxy clustering), Ly-α, HST
Fogli et al.PRD 70 (2004) 113003
0.47WMAP, other CMB, 2dF, SDSS (Ly-α),HST
Seljak et al.PRD (2005) [astro-ph/0407372]
0.42WMAP, SDSS (bias, galaxy clustering, Ly-α)
Neutrino masses in 3-neutrino schemes
Fig from Strumia & Vissani, hep-ph/0503246
CMB + galaxy clustering
+ HST, SNI-a [σ8]
+ Ly-α [bias]
Global analysis: oscillations + tritium decay + 02 + Cosmology
Fogli et al., PRD 70 (2004) 113003
CMB + 2dF
390280640 . . .
Bound on Σmν (eV) at 95% CL
Data used
Ichikawa, Fukugita & KawasakiPRD 71 (2005) 043001
2.0 WMAP
SDSS Coll.PRD 69 (2004) 103501
1.7 WMAP, SDSS
HannestadJCAP 0305 (2003) 004
1.01 WMAP, other CMB, 2dF, HST
Crotty, Lesgourgues & SPPRD 69 (2004) 123007
1.0 [0.6] WMAP, other CMB, 2dF, SDSS [HST,SN]
Barger. Marfatia & TregrePLB 595 (2004) 55
0.75 WMAP, other CMB, 2dF, SDSS, HST
WMAP Coll.ApJ Suppl 148 (2003) 175
0.7
WMAP, other CMB,2dF (bias,galaxy clustering), Ly-α, HST
Fogli et al.PRD 70 (2004) 113003
0.47WMAP, other CMB, 2dF, SDSS (Ly-α),HST
Seljak et al.PRD (2005) [astro-ph/0407372]
0.42WMAP, SDSS (bias, galaxy clustering, Ly-α)
Allen, Smith & BridleMNRAS 346 (2003) 593
WMAP, other CMB, 2dF, X-ray galaxy cluster
390280640 . . .
The bound depends on the number of neutrinos
• Example: in the 3+1 scenario, there are 4 neutrinos (including thermalized sterile)
• Calculate the bounds with Nν > 3
Abazajian 2002, di Bari 2002
Hannestad JCAP 0305 (2003) 004
(also Elgarøy & Lahav, JCAP 0304 (2003) 004)
3 ν4 ν
5 ν
Hannestad
95% CL
WMAP + Other CMB + 2dF + HST + SN-Ia
Σmν and Neff degeneracy
(0 eV,3)
(0 eV,7)
(2.25 eV,7)(0 eV,3)
(0 eV,7)
(2.25 eV,7)
Analysis with Σmν and Neff free
Hannestad & Raffelt, JCAP 0404 (2004) 008
Crotty, Lesgourgues & SP, PRD 69 (2004) 123007
2σ upper bound on Σmν (eV)
WMAP + ACBAR + SDSS + 2dF Previous + priors (HST + SN-Ia)
Non-thermal relic neutrinos
The spectrum could be distorted after neutrino decoupling
Example: decay of a
light scalar after BBN
Cuoco, Lesgourgues, Mangano & SP, astro-ph/0502465
Thermal FD spectrum
Distortion from decay
CMB + LSS data still compatible with large deviations from a thermal neutrino spectrum (degeneracy NT distortion – Neff)
* Better expectations for future CMB + LSS data, but model degeneracy NT- Neff remains
/T p
Future sensitivities to Σmν
• Next CMB data from WMAP and PLANCK (+ other CMB experiments on large l’s) temperature and polarization spectra
• SDSS galaxy survey: 106 galaxies (250,000 for 2dF)
• Fisher matrix analysis: expected sensitivities assuming a fiducial cosmological model
• Forecast analysis for
WMAP and ΩΛ=0 models Hu et al, PRL 80 (1998) 5255
Sensitivity to
With current best-fit values
eV 0.1N
hΩ 0.65 Σm
0.82m
νν
eV0.37 Σm
Recent update: Lesgourgues, SP & Perotto, PRD 70 (2004) 045016
Fiducial cosmological model:(Ωbh2 , Ωmh2 , h , ns , τ, Σmν ) = (0.0245 , 0.148 , 0.70 , 0.98 , 0.12, Σmν )
PLANCK+SDSS
Lesgourgues, SP & Perotto, PRD 70 (2004) 045016
Ideal CMB+40xSDSS
Σm detectable at 2σ if larger than
0.21 eV (PLANCK+SDSS)
0.13 eV (CMBpol+SDSS)
Σm Σm
Fiducial value
2 sensitivity
Future sensitivities to Σmν: new ideas
galaxy weak lensing and CMB lensing
no bias uncertaintysmall scales in linear regime
makes CMB sensitive to much smaller masses
Future sensitivities to Σmν: new ideas
galaxy weak lensing and CMB lensing
sensitivity of future weak lensing survey(4000º)2 to mν
σ(mν) ~ 0.1 eV
Abazajian & DodelsonPRL 91 (2003) 041301
sensitivity of CMB(primary + lensing) to mν
σ(mν) = 0.15 eV (Planck)
σ(mν) = 0.044 eV (CMBpol)
Kaplinghat, Knox & SongPRL 91 (2003) 241301
Neutrino masses in 3-neutrino schemes
Fig from Strumia & Vissani, hep-ph/0503246
CMB + galaxy clustering
+ HST, SNI-a [σ8]
+ Ly-α [bias]
PLANCK + SDSS
CMBpol + SDSS
CMBpol (including CMB lensing)
KATRIN
Bounds on the sum of neutrino masses from CMB + 2dFGRS or SDSS, and other
cosmological data (best Σmν<0.42 eV, conservative Σmν<1 eV)
Conclusions
Sub-eV sensitivity in the next future (0.1-0.2 eV and better) Test degenerate
mass region and eventually the IH case
ν
Cosmological observables efficiently constrain some properties of (relic) neutrinos