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NEUTRINO MASS BOUNDS FROM COSMOLOGICAL OBSERVABLES

NEUTRINO MASS BOUNDS FROM COSMOLOGICAL OBSERVABLES. ν. Sergio Pastor (IFIC). XIth International Workshop on Neutrino Telescopes, Venice Feb 2005. NEUTRINO MASS BOUNDS FROM COSMOLOGY. Relic neutrinos. Effect of neutrino mass on cosmological observables. Current bounds and

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NEUTRINO MASS BOUNDS FROM COSMOLOGICAL OBSERVABLES

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  1. NEUTRINO MASS BOUNDS FROM COSMOLOGICAL OBSERVABLES ν Sergio Pastor (IFIC) XIth International Workshop on Neutrino Telescopes, Venice Feb 2005

  2. NEUTRINO MASS BOUNDS FROM COSMOLOGY Relic neutrinos Effect of neutrino mass on cosmological observables Current bounds and future sensitivities

  3. NEUTRINO MASS BOUNDS FROM COSMOLOGY Relic neutrinos Effect of neutrino mass on cosmological observables Current bounds and future sensitivities

  4. Standard Relic Neutrinos Neutrinos in equilibrium fν(p,T)=fFD(p,T)

  5. Neutrinos in Equilibrium 1 MeV  T mμ Tν= Te = Tγ

  6. Neutrino decoupling

  7. Neutrino decoupling Tdec(νe) ~ 2.3 MeV Tdec(νμ,τ) ~ 3.5 MeV Decoupled Neutrinos fν(p)=fFD(p,Tν)

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

  9. The Cosmic Neutrino Background • Number density • Energy density Massless Massive mν>>T

  10. Neutrinos and Cosmology Neutrinos influence several cosmological epochs

  11. Using 4He + D data (2σ) Cuoco et al, IJMP A 19 (2004) 4431 Baryon abundance Primordial Nucleosynthesis: allowed ranges for Neff Non-instantaneous decoupling + Flavor Oscillations Neff=3.045(5) T.Pinto et al, in preparation

  12. NEUTRINO MASS BOUNDS FROM COSMOLOGY Relic neutrinos Effect of neutrino mass on cosmological observables Current bounds and future sensitivities

  13. CMB DATA: FIRST YEAR WMAP vs COBE

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

  15. Galaxy Surveys 2dFGRS SDSS

  16. 2dFGRS Galaxy Survey ~ 1300 Mpc

  17. Field of density Fluctuations CMB experiments SDSS Galaxy Surveys Matter power spectrum is the Fourier transform of the two-point correlation function Power Spectrum of density fluctuations

  18. SDSS kmax Power spectrum of density fluctuations Bias b2(k)=Pg(k)/Pm(k) Non-linearity 2dFGRS

  19. 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 n F b, cdm

  20. 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

  21. W. Hu Neutrinos as Hot Dark Matter Massive Neutrinos can still be subdominant DM: limits on mν from Structure Formation • Effect of Massive Neutrinos: suppression of Power at small scales

  22. Effect of massive neutrinos on the CMB and Matter Power Spectra Max Tegmark www.hep.upenn.edu/~max/

  23. NEUTRINO MASS BOUNDS FROM COSMOLOGY Relic neutrinos Effect of neutrino mass on cosmological observables Current bounds and future sensitivities

  24. Cosmological bounds on neutrino mass(es) A unique cosmological bound on mνDOES 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

  25. Cosmological Parameters: example SDSS Coll, PRD 69 (2004) 103501

  26. 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), …

  27. Absolute mass scale searches

  28. eV m0 Neutrino masses in 3-neutrino schemes From present evidences of atmospheric and solar neutrino oscillations eV solar atm atm solar 3 degenerate massive neutrinos Σmν = 3m0

  29. Neutrino masses in 3-neutrino schemes

  30. Bound on mν after first year WMAP data 3 degenerate massive neutrinos Σmν < 0.7 eV Ωνh2 < 0.0076 More conservative Σmν < 1.01 eV Including also SDSS Σmν < 0.75 eV Hannestad JCAP 0305 (2003) 004 Elgarøy & Lahav JCAP 0305 (2003) 004 95% CL m0 < 0.23 eV Barger et al, PLB 595 (2004) 55 WMAP+CBI+ACBAR+2dFGRS+σ8+Lyman α Spergel et al ApJ. Suppl.148 (2003) 175

  31. Cosmological bounds on neutrino mass since 2003

  32. Neutrino masses in 3-neutrino schemes Currently disfavored

  33. Global analysis:  oscillations + tritium  decay + 02 + Cosmology CMB + 2dF Fogli et al., PRD 70 (2004) 113003

  34. WMAP + Other CMB + 2dF + HST + SN-Ia 3 ν 4 ν Hannestad JCAP 0305 (2003) 004 (also Elgarøy & Lahav, JCAP 0304 (2003) 004) 95% CL 5 ν Hannestad 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

  35. Σmν and Neff degeneracy (0 eV,3) (0 eV,7) (2.25 eV,7)

  36. Analysis with Σmν and Neff free Previous + priors (HST + SN-Ia) WMAP + ACBAR + SDSS + 2dF 2σ upper bound on Σmν (eV) Hannestad & Raffelt, JCAP 0404 (2004) 008 Crotty, Lesgourgues & SP, PRD 69 (2004) 123007

  37. ThermalFD spectrum Distortion from  decay Cuoco, Lesgourgues, Mangano & SP, astro-ph/0502465 Non-thermal relic neutrinos  The spectrum could be distorted after neutrino decoupling Example: decay of a light scalar after BBN • 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

  38. Sensitivity to With current best-fit values 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) • Forecast analysis in WMAP and ΩΛ=0 models Hu et al, PRL 80 (1998) 5255

  39. Analysis of future bounds on Σmν • Forecast analysis calculating theFisher matrix Fij + CMB part Galaxy Survey part Veff ~ effective volume of the galaxy survey Estimator of the error on parameter θi Fiducial cosmological model: (Ωbh2 , Ωmh2 , h , ns , τ, Σmν) = (0.0245, 0.148, 0.70 , 0.98, 0.12,Σmν)

  40. Ideal CMB+40xSDSS PLANCK+SDSS Lesgourgues, SP & Perotto, PRD 70 (2004) 045016

  41. Analysis of future sensitivities on Σmν: 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 !!!

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

  43. galaxy weak lensing and CMB lensing Future sensitivities to Σmν: new ideas sensitivity of future weak lensing survey (4000º)2 to mν σ(mν) ~ 0.1 eV Abazajian & Dodelson PRL 91 (2003) 041301 sensitivity of CMB (primary + lensing) to mν σ(mν) = 0.15 eV (Planck) σ(mν) = 0.04 eV (CMBpol) Kaplinghat, Knox & Song PRL 91 (2003) 241301

  44. Conclusions Cosmological observables efficiently constrain some properties of (relic) neutrinos ν 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) Sub-eV sensitivity in the next future (0.1-0.2 eV and better)  Test degenerate mass region and eventually the IH case

  45. FINE

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