1. Neutrino Masses in Cosmology
Carlos Peña Garay
IFIC, Valencia
Jimenez et al,
Villaescusa et al, ,
Nov 18th, 2011
GDR meeting, Annecy

2. Neutrino and impact on observables
~ 1s ~ 0.3 Myr ~ 1-10 Gyr
Neutrino Photon LSS
Decoupling
Influence in background and growth of structure

3. Neutrinos in the early universe:
Radiation density after neutrino decoupling and BBN (T< me):
At present per flavour

4. Extra light states Blue: CMB+HST+SDSS Red: CMB+HST+SDSS +SN-Ia
Giusarma et al.,

5. Evolution of background density
photons
neutrinos
cdm
baryons Λ
Ωi= ρi/ρcrit
m=1 eV
m=0.05 eV
m=0.009 eV
m≈ 0 eV
Lesgourgues-Pastor

6. Neutrino mass influence in linear P(k)
- Change in matter-radiation equality
- Suppression of power on scales smaller than the free-streaming scale
0.05 eV
0.5 eV

7. Linear and non Linear P(k)

8. Cosmological probes of neutrino mass
95%

9. Cosmological probes of neutrino mass
95%
arXiv: 1103:5083

10. n mass and the Weakest force
Impact of single neutrino masses ?
Can we see the neutrino hierarchy in the sky ?

11. Parameterization: S, D, sgn(D)
Solar splitting can be safely neglected ( < 1%)

12. P(k) dependence on D
Numerical with
CAMB

13. NH-IH quasi-degeneracy
No distinguishable NH-IH
Delta could be measured ! Handle to identify neutrinos

14. Can we see n-hierarchy in the sky?
Full sky, variance-dominated
Gal survey, 600 Gpc3 (z<2) WL survey (<z> < 3)
21cm HI, 2000 Gpc3 (z<5) gal / sq-arcmin

15. n mass and the Weakest force
Beyond linear order:
Nonlinear effects of neutrinos in the dark matter power spectrum
Observable effects in the deepest and shallowest DM potential wells

16. Facing the tiniest and the biggest (mass)
mn ~ kg MCOMA ~ kg

17. Dark matter profile: NFW + EL
Zhao et al, AJ’09
Mvir (Msun) Rvir (Mpc) rhoc Rs (Mpc)
z= e e
z= e e
z= e e

18. n overdensity
M=1015 Msun
Large neutrino overdensity (~linear with cluster mass)
Interesting region around Mpc scale
Best observable: Convergence measured by Weak Lensing

19. Convergence
Observable proportional to column density

20. Relative convergence due to n
z=1
z=0.4
0.3 eV - 10^4 clusters to obtain a 5-s result
Expected in a full-sky weak lensing survey
N-body simulation (in progress):
needed to confirm signal and study systematics

21. Facing the tiniest and the emptiest
Voids : Underdense regions
(z=0: from ~ 0 to ~ 0.3 times the mean density at 10 Mpc)
Neutrinos make them smaller and denser : delay the rate
at which DM is evacuated
Density contrast decreases by 10% for S = 1eV
Statistics of voids depends on S and s8
Observable: Lyman-a signature (quasar at z=2.2, z=4) of low density regions

22. High Transmission regions if the Ly-a forest
N-body simulations
4500 random line of sight
Compute transmitted flux
Count weak absorption region

23. Sensitivity to neutrino mass
PDF for the number of regions (100/h Mpc) above threshold
Degeneracy could be broken by using several redshift quasar
Study of systematics: calibrating the flux at weak absorption

24. Conclusions
Cosmological neutrinos expected to be indirectly seen in cosmological data: Relativistic energy seeen in CMB, and total mass by CMB & LSS.
Linear growth will be sensitive to the atmospheric splitting: handle to verify neutrino nature of the total mass effect. Difficult to distinguish NH from IH unless total mass < 0.1 eV.
Study nonlinear effects: N-body simulations
Neutrinos in clusters: Clean (mostly DM) but high precision needed ( < 1 %)
Impact of neutrinos in voids: Not clean (baryons) but larger signal (~ 10%)

25. Extra light states Blue: WMAP-7
Red: w7+SN+Bao+H0 Green: w7+CMBsuborb+SN+LRG+H0
[eV]

26. Neutrino mass by the Weak Force
Normal Hierarchy
Inverted Hierarchy
Degenerate

27. Neutrino mass by the Weak Force
If q13=0
NH~IH
Gonzalez-Garcia et al 2010
Different pattern for leptons and quarks

28. Neutrinoless double beta decay
Are neutrinos Dirac or Majorana?
0nbb: nn  ppe–e– without neutrinos me
|<mnee>| =
(T1/2 FN )1/2
FN = G0n |M0nf – (gA/ gV)2 M0nGT |2

29. Mass scale onbb: predictions
Present
experiments
aim at IH scale
NH may lead to
negligible signal j
|<mnee>| = |S mj Uej2 | = |S mj | Uej | 2 eif |

30. Mass scale searches: beta decay 0nbb decay cosmology
If Majorana neutrinos
Reid et al 2010, …