Implications of absolute neutrino mass on cosmological parameter - - PowerPoint PPT Presentation

Implications of absolute neutrino mass

• n cosmological parameter estimation

Kazuhide Ichikawa (Institute for Cosmic Ray Research) International Workshop on Double Beta Decay and Neutrinos, Osaka, June 2007

KI, M. Fukugita & M. Kawasaki, PRD71 043001 (2005)

• M. Fukugita, KI, M. Kawasaki & O. Lahav, PRD74 027302 (2006)

KI & M. Fukugita , in preparation

Ichikawa (2005) Hannestad (2005) MacTavish (2006) Sanchez (2006) Goobar (2006) Spergel (2006) Seljak (2006) Fukugita (2006) Feng (2006) Cirelli (2006)

mν (eV)

1.0 CMB only Galaxy power (shape) Galaxy bias and/

• r Ly alpha

Conservative Moderate Aggresive

Croft (1999) Fukugita (2000) Wang (2002) Elgaroy (2002) Hannestad (2002) Lewis (2002) Spergel (2003) Hannestad (2003) Allen (2003) Tegmark (2004) Barger (2004) Crotty (2004) Seljak (2005) Seljak (2005)

CMB only Galaxy power (shape) Galaxy bias and/

• r Ly alpha

mν (eV)

1.0 Conservative Moderate Aggresive

There are many works to derive constraint on neutrino masses from cosmological data.

WMAP3 (full data) WMAP3 (w/o polarization) WMAP1

KI, Fukugita & Kawasaki, PRD71 043001 (2005) Fukugita, KI, Kawasaki & Lahav, PRD74 027302 (2006)

analysis χ2

(We marginalized over 6 other LCDM cosmological parameters) ~95% CL limit 2 4 6 8 10 12 14 0.2 0.4 0.6 0.8 1 1.2

WMAP3 limit (95%CL) : mν < 0.7 eV

There are many works on cosmological constraint

• n neutrino masses.

Ichikawa (2005) Hannestad (2005) MacTavish (2006) Sanchez (2006) Goobar (2006) Spergel (2006) Seljak (2006) Fukugita (2006) Feng (2006) Cirelli (2006)

mν (eV)

1.0 CMB only Galaxy power (shape) Galaxy bias and/

• r Ly alpha

Conservative Moderate Aggresive

Croft (1999) Fukugita (2000) Wang (2002) Elgaroy (2002) Hannestad (2002) Lewis (2002) Spergel (2003) Hannestad (2003) Allen (2003) Tegmark (2004) Barger (2004) Crotty (2004) Seljak (2005) Seljak (2005)

CMB only Galaxy power (shape) Galaxy bias and/

• r Ly alpha

mν (eV)

1.0 Conservative Moderate Aggresive

What if some experiment detected neutrino mass ?

We need cosmological parameter estimation fixing neutrino mass to some finite value. Assuming massless neutrinos.

http://lambda.gsfc.nasa.gov/

We need cosmological parameter estimation fixing neutrino mass to some finite value.

http://lambda.gsfc.nasa.gov/

The Hubble constant decreases significantly by the finite neutrino mass.

mν ∼ 0.5 eV H0 ∼ 60

H0 = 73.2 ± 3.1

for massless case.

( )

We assume flat Lambda CDM model (6 parameters) + neutrino mass baryon density CDM density Hubble constant epoch of reionization amplitude of fluctuation a slope for the scalar perturbation Hubble constant (expansion rate at present): H0

H0 = 100 h km/s/Mpc

neutrino mass (for one generation): mν We assume three generations and the masses are degenerate.

ων = 3 mν 94 eV

neutrino mass density (relative to the critical density) 1 eV corresponds to ων ∼ 0.03 (cf. )

ωCDM ∼ 0.105

Electron Proton Photon Helium atom Helium nucleus Hydrogen atom Early galaxies Modern galaxies Neutron First stars CMB radiation

Electron Proton Neutron Photon He atom He nucleus

4 4

H atom CMB radiation First stars Early galaxies Modern galaxies T

• d

a y R e c

• m

b i n a t i

• n

R e i

• n

i z a t i

• n

~300 Mpc ~14000 Mpc ~1 degree

T ∼ 0.6 eV

mν ↑

H0 ↓

Longer distance ∼ cH−1 Shorter distance ( becomes nonrelativistic)

ν

CMB angular spectrum

Large contrast at ~1 degree

mν ↑ H0 ↓

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.2 0.4 0.6 0.8 1

F r e e d m a n ( 2 1 ) M a c r i ( 2 6 ) S a n d a g e ( 2 6 )

72 ± 8 62.3 ± 1.3 ± 5.0 74 ± 3 ± 6 h mν (eV)

Hubble constant from WMAP3 assuming massive neutrinos Direct measurements of Hubble constant This is not the end of the story ! [1 sigma Error bars]

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.2 0.4 0.6 0.8 1

h mν (eV)

Assume h is measured with a total uncertainty of 5%

A determination of H0 to 5% (see Table 7) is a con- servative goal for the near term. It will require the re- A determination of H0 to 5% (see servative goal for the near term. It estimation of a maser distance to NGC

Macri et al. ApJ 652, 1133, 2006

Conclusion If neutrino mass is detected to be > 0.3 eV, it is consistent with people claiming small Hubble constant. ~ If not detected, upper bound of < 0.3 eV is very useful because uncertainty of is one of the largest systematic errors for estimating cosmological parameters from CMB (most notably for Hubble constant).

mν mν

These correlation between and holds if we combine CMB data with Supernova and galaxy clustering data. It is also expected to hold in the Planck era.

H0 mν

~