04/11/23

Cosmological Aspects of Neutrino Physics (III)

Sergio Pastor (IFIC)61st SUSSP

St Andrews, August 2006

ν

Neutrino Physics and Cosmology

3rd lecture

Bounds on mν from CMB, LSS and other data

Bounds on the radiation content (Neff)

Future sensitivities on mν from cosmology

Effect of massive neutrinos on the CMB and Matter Power

Spectra

Max Tegmark

www.hep.upenn.edu/~max/

Neutrinos as Hot Dark Matter

Massive Neutrinos can still be subdominant DM: limits on mν from Structure Formation (combined with other cosmological data)

How to get a bound (measurement) of neutrino masses from Cosmology

DATA

Fiducial cosmological model:(Ωbh2 , Ωmh2 , h , ns , τ, Σmν )

PARAMETERESTIMATES

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

* Baryon acoustic oscillations (SDSS)

Bounds on parameters from other data: SNIa (Ωm), HST (h), …

Cosmological Parameters: example

SDSS Coll, PRD 69 (2004) 103501

Cosmological bounds on neutrino mass(es)

A unique cosmological bound on mν DOES NOT exist !

ν

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 combination of cosmological data used

• The assumed cosmological model: number of parameters (problem of parameter degeneracies)

• The properties of relic neutrinos

Cosmological bounds on neutrino masses using WMAP1

390280640 . . .

Bound on Σmν (eV) [95% CL]

Data used

Ichikawa et al, PRD 71 (2005) 043001Sánchez et al, MNRAS 366 (2006) 189MacTavish et al, astro-ph/0507503

1.6 - 3.1 CMB only

Hannestad, JCAP 0305 (2003) 004 SDSS Coll., PRD 69 (2004) 103501Barger et al, PLB 595 (2004) 55Crotty et al, PRD 69 (2004) 123007Rebolo et al, MNRAS 353 (2004) 747Fogli et al. PRD 70 (2004) 113003Seljak et al, PRD 71 (2005) 103515Sánchez et al, MNRAS 366 (2006) 189MacTavish et al, astro-ph/0507503

1.0 - 1.7 [0.6-1.2]

WMAP1, other CMB, 2dF/SDSS-gal [HST,SNIa]

WMAP Coll., ApJ Suppl 148 (2003) 175Fogli et al. PRD 70 (2004) 113003 Seljak et al, PRD 71 (2005) 103515MacTavish et al, astro-ph/0507503Hannestad, hep-ph/0409108

0.42-0.68

WMAP1, other CMB, 2dF/SDSS-gal, 2dF/SDSS-bias and/or Ly-α

Cosmological bounds on neutrino masses using WMAP3

390280640 . . .

Bound on Σmν (eV) [95% CL] Data used

WMAP Coll., astro-ph/0603449Fukugita et al, astro-ph/0605362Kristiansen et al, astro-ph/0608017

1.7 – 2.3 CMB only

WMAP Coll., astro-ph/0603449Goobar et al, astro-ph/0602155

0.68 – 0.91WMAP3, other CMB, 2dF/SDSS-gal, SNIa

Goobar et al, astro-ph/0602155Seljak et al, astro-ph/0604335Kristiansen et al, astro-ph/0608017

0.17-0.48

WMAP3, other CMB, 2dF/SDSS-gal, SDSS-BAO and/or Ly-α

Fogli et al., hep-ph/0608060

Neutrino masses in 3-neutrino schemes

Fig from Strumia & Vissani, NPB726(2005)294

CMB + galaxy clustering

+ HST, SNI-a…

+ BAO and/or bias

+ including Ly-α

Tritium decay, 02 and Cosmology

Fogli et al.,

hep-ph/0608060

02 and Cosmology

Fogli et al., hep-ph/0608060

Parameter degeneracy: Neutrino mass and w

In cosmological models with more parameters the neutrino mass bounds can be relaxed.

Ex: quintessence-like dark energy with ρDE=w pDE

WMAP Coll, astro-ph/0607101

Λ

At T<me, the radiation content of the Universe is

Effective number of relativistic neutrino speciesTraditional parametrization of the energy densitystored in relativistic particles

Relativistic particles in the Universe

• Extra radiation can be:

scalars, pseudoscalars, sterile neutrinos (totally or partially thermalized, bulk), neutrinos in very low-energy reheating scenarios, relativistic decay products of heavy particles…

• Particular case: relic neutrino asymmetries

Constraints on Neff from BBN and from CMB+LSS

Extra relativistic particles

Effect of Neff at later epochs

• Neff modifies the radiation content:

• Changes the epoch of matter-radiation equivalence

CMB+LSS: allowed ranges for Neff

• Set of parameters: ( Ωbh2 , Ωcdmh2 , h , ns , A , b , Neff )

• DATA: WMAP + other CMB + LSS + HST (+ SN-Ia)

• Flat Models

Non-flat Models

• Recent result

Pierpaoli, MNRAS 342 (2003)

2.01.9eff 4.1N

95% CL

Crotty, Lesgourgues & SP, PRD 67 (2003)

3.32.1eff 3.5N

95% CL

Hannestad, JCAP 0305 (2003)

3.02.1eff 4.0N

Hannestad & Raffelt, astro-ph/06071014.6N2.7 eff

95% CL

Future bounds on Neff

• Next CMB data from WMAP and PLANCK (other CMB experiments on large l’s) temperature and polarization spectra

• Forecast analysis in ΩΛ=0 modelsLopez et al, PRL 82 (1999) 3952

WMAP

PLANCK

Future bounds on Neff

Updated analysis:Larger errors

Bowen et al 2002

ΔNeff ~ 3 (WMAP)

ΔNeff ~ 0.2 (Planck)

Bashinsky & Seljak 2003

The bound on Σmν 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)

Analysis with Σmν and Neff free

Crotty, Lesgourgues & SP, PRD 69 (2004) 123007

WMAP + ACBAR + SDSS + 2dF

Hannestad & Raffelt, astro-ph/0607101

Non-standard relic neutrinos

The cosmological bounds on neutrino masses are modified if relic neutrinos have non-standard properties (or for non-standard models)

Two examples where the cosmological bounds do not apply

• Massive neutrinos strongly coupled to a light scalar field: they could annihilate when becoming NR

• Neutrinos coupled to the dark energy: the DE density is a function of the neutrino mass (mass-varying neutrinos)

Non-thermal relic neutrinos

The spectrum could be distorted after neutrino decoupling

Example: decay of a light scalar after BBN

Cuoco, Lesgourgues, Mangano & SP, PRD 71 (2005) 123501

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

1. CMB (T+P) + galaxy redshift surveys

2. CMB (T+P) and CMB lensing

3. Weak lensing surveys

4. Weak lensing surveys + CMB lensing

When future cosmological data will be available

PLANCK+SDSS

Lesgourgues, SP & Perotto, PRD 70 (2004) 045016

Σm detectable at 2σ if larger than

0.21 eV (PLANCK+SDSS)

0.13 eV (CMBpol+SDSS)

Fiducial cosmological model:(Ωbh2 , Ωmh2 , h , ns , τ, Σmν ) =

(0.0245 , 0.148 , 0.70 , 0.98 , 0.12, Σmν )

• Fisher matrix analysis: expected sensitivities assuming a fiducial cosmological model, for future experiments with known specifications

Future sensitivities to Σmν: new ideas

weak gravitational and CMB lensing

lensing

No bias uncertaintySmall scales much closer

to linear regimeTomography:

3D reconstruction

Makes CMB sensitive to smaller neutrino masses

Future sensitivities to Σmν: new ideas

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

weak gravitational and CMB lensing

lensing

CMB lensing: recent analysis

σ(Mν) in eV for future CMB experiments alone : Lesgourgues et al, PRD 73 (2006) 045021

Summary of future sensitivities

Lesgourgues & SP, Phys. Rep. 429 (2006) 307

Future cosmic shear surveys

End of 3rd lecture