WG1 NuFact04, Osaka, July Neutrino mass and Cosmology: current bounds and future sensitivities Sergio Pastor (IFIC) ν

Current bounds and future sensitivities Relic neutrinos Effect of neutrino mass on cosmological observables NEUTRINO MASS AND COSMOLOGY

Current bounds and future sensitivities Relic neutrinos Effect of neutrino mass on cosmological observables NEUTRINO MASS AND COSMOLOGY

Neutrinos in equilibrium f ν (p,T)=f FD (p,T) Standard Relic Neutrinos

T ν = T e = T γ 1 MeV  T  m μ Neutrinos in Equilibrium

Neutrino decoupling

Decoupled Neutrinos f ν (p)=f FD (p,T ν ) T dec ( ν e ) ~ 2.3 MeV T dec ( ν μ,τ ) ~ 3.5 MeV Neutrino decoupling

At T~m e, electron-positron pairs annihilate heating photons but not the decoupled neutrinos Decoupled neutrinos stream freely until non-relativistic Neutrino and Photon temperatures

Number density Energy density The Cosmic Neutrino Background Massless Massive m ν >>T

Neutrinos and Cosmology Neutrinos influence several cosmological scenarios Primordial Nucleosynthesis BBN Cosmic Microwave Background CMB Formation of Large Scale Structures LSS T~MeVT<eV ν e vs ν μ,τ N ν No flavor sensitivity N ν & m ν

Primordial Nucleosynthesis: allowed ranges for N eff Cuoco et al astro-ph/ Using 4 He + D data (2σ) Baryon abundance

Current bounds and future sensitivities Relic neutrinos Effect of neutrino mass on cosmological observables NEUTRINO MASS AND COSMOLOGY

CMB DATA: FIRST YEAR WMAP vs COBE

Map of CMBR temperature Fluctuations Multipole Expansion CMB DATA: INCREASING PRECISION Angular Power Spectrum

Power Spectrum of density fluctuations Galaxy Surveys CMB experiments SDSS

Galaxy Surveys 2dFGRSSDSS

2dFGRS Galaxy Survey ~ 1300 Mpc

Power spectrum of density fluctuations Bias b 2 (k)=P g (k)/P m (k) Non-linearity 2dFGRS k max SDSS

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 Neutrino Free Streaming  b, cdm

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

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 m ν from Structure Formation

Effect of massive neutrinos on the CMB and Matter Power Spectra Max Tegmark’s homepage

Current bounds and future sensitivities Relic neutrinos Effect of neutrino mass on cosmological observables NEUTRINO MASS AND COSMOLOGY

Cosmological bounds on neutrino mass(es) A unique cosmological bound on m ν DOES NOT exist ! Different analyses have found upper bounds on neutrino masses, but 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)

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,σ 8 ) * Lyman-α forest: independent measurement of power on small scales Priors on parameters from other data: SNIa (Ω m ), HST (h), …

Cosmological bounds on neutrino mass(es) A unique cosmological bound on m ν DOES NOT exist ! Different analyses have found upper bounds on neutrino masses, but they depend on The assumed cosmological model: number of parameters (problem of parameter degeneracies) The combination of cosmological data used WMAP data is consistent with ν’ s being all the DM ( Σm ν < 13 eV ). The WMAP bound on Σm ν is a VERY weak bound ! SDSS Coll PRD 69 (2004)

Absolute mass scale searches Cosmology < eV Tritium beta decay < 2.3 eV Neutrinoless double beta decay < eV

3 degenerate massive neutrinos Σm ν = 3m 0` Neutrino masses in 3-neutrino schemes eV From present evidences of atmospheric and solar neutrino oscillations atm solar eV m0m0

Neutrino masses in 3-neutrino schemes

WMAP+CBI+ACBAR+2dFGRS+σ 8 +Lyman α Spergel et al ApJ. Suppl.148 (2003) 175 Σm ν < 0.7 eV Ω ν h 2 < m 0 < 0.23 eV 95% CL 3 degenerate massive neutrinos Bound on m ν after first year WMAP data More conservative Σm ν < 1.01 eV Including also SDSS Σm ν < 0.75 eV Hannestad JCAP 0305 (2003) 004 Elgarøy & Lahav JCAP 0305 (2003) 004 Barger et al, PLB 595 (2004) 55

Cosmological bounds on neutrino mass (2003/04) Bound on Σm ν (eV) at 95% CL Data used WMAP Coll. ApJ Suppl 148 (2003) WMAP, other CMB, 2dF, σ 8(a), HST Hannestad JCAP 0305 (2003) WMAP, other CMB, 2dF, HST Allen, Smith & Bridle MNRAS 346 (2003) 593 WMAP, other CMB, 2dF, σ 8(b), X-ray galaxy cluster SDSS Coll. PRD 69 (2004) WMAP, SDSS Barger. Marfatia & Tregre PLB 595 (2004) WMAP, other CMB, 2dF, SDSS, HST Crotty, Lesgourgues & SP PRD 69 (2004) (0.6) WMAP, other CMB, 2dF, SDSS (HST) Seljak et al. astro-ph/ WMAP, SDSS (bias, galaxy clustering, Ly-α)

Neutrino masses in 3-neutrino schemes Currently disfavored

The real bound depends on the number of neutrinos Example: in the 3+1 scenario, there are 4 neutrinos (including thermalized sterile) Calculate the bounds with N ν > 3 Abazajian 2002, di Bari 2002 Hannestad JCAP 0305 (2003) 004 (also Elgarøy & Lahav, JCAP 0304 (2003) 004) 3 ν 4 ν 5 ν Hannestad 95% CL WMAP + Other CMB + 2dF + HST + SN-Ia

Σm ν and N eff degeneracy (0 eV,3) (0 eV,7) (2.25 eV,7)

Analysis with Σm ν and N eff free Hannestad & Raffelt, JCAP 0404 (2004) 008 Crotty, Lesgourgues & SP, PRD 69 (2004) σ upper bound on Σm ν WMAP + ACBAR + SDSS + 2dF Previous + priors (HST + SN-Ia)

Future sensitivities to Σm ν Next CMB data from WMAP and PLANCK (+other CMB experiments on large l’s) temperature and polarization spectra SDSS galaxy survey: 10 6 galaxies (250,000 for 2dF) Forecast analysis in WMAP and Ω Λ =0 models Hu et al, PRL 80 (1998) 5255 Sensitivity to With current best-fit values

Analysis of future bounds on Σm ν Forecast analysis calculating the Fisher matrix F ij CMB part + Galaxy Survey part Veff ~ effective volume of the galaxy survey Estimator of the error on parameter θ i Fiducial cosmological model: (Ω b h 2, Ω m h 2, h, n s, τ, Σm ν ) = (0.0245, 0.148, 0.70, 0.98, 0.12, 0.12 eV )

PLANCK+SDSS Ideal CMB+40xSDSS Lesgourgues, SP & Perotto, hep-ph/ (PRD)

Analysis of future sensitivities on Σm ν : summary Σm detectable at 2σ if larger than 0.21 eV (PLANCK+SDSS) 0.13 eV (CMBpol+SDSS) 0.07 eV (ideal+40xSDSS) measure absolute ν mass scale !!!

Future sensitivities to Σm ν : new ideas galaxy weak lensing and CMB lensing no bias uncertainty small scales in linear regime makes CMB sensitive to much smaller masses

Future sensitivities to Σm ν : new ideas galaxy weak lensing and CMB lensing sensitivity of future weak lensing survey (4000º) 2 to m ν σ(m ν ) ~ 0.1 eV Abazajian & Dodelson PRL 91 (2003) sensitivity of CMB (primary + lensing) to m ν σ(m ν ) = 0.15 eV (Planck) σ(m ν ) = 0.04 eV (CMBpol) Kaplinghat, Knox & Song PRL 91 (2003)

Cosmological observables efficiently constrain some properties of (relic) neutrinos Bounds on the sum of neutrino masses from CMB + 2dFGRS or SDSS, and other cosmological data (best Σm ν <0.42 eV, conservative Σm ν <1 eV) Conclusions Sub-eV sensitivity in the next future ( eV and better)  Test degenerate mass region and eventually the IH case ν