Neutrino properties from cosmological measurements

1. Neutrino properties from cosmological measurements Olga Mena IFIC-CSIC/UV Cosmorenata June’13 1

2. Introduction • Neutrino masses: Cosmological signatures, current bounds & future perspectives • Relativistic degrees of freedom Neff: Cosmological signatures, current bounds & future perspectives

3. According to standard cosmology, there are three active Dirac or Majorana neutrinos, which decouple from the thermal bath at a temperature O(1 MeV): They do not inherit any of the energy associated to e+ e- annihilations, being colder than photons: If these neutrinos are massive, their energy density, at T<<m is and their thermal motion

4. According to neutrino oscillation physics, we know that there are at lest two Dirac or Majorana massive neutrinos: (Schwetz, Tortola &Valle, NJP’11) (Mena,Parke, PRD’04) Cosmorenata June’13 4

5. According to neutrino oscillation physics, we know that there are at lest two Dirac or Majorana massive neutrinos: (Schwetz, Tortola &Valle, NJP’01) which translates into a lower bound on the total neutrino mass, depending on the hierarchy:

6. What ingredient, in your opinion, should be mandatory to change in the ΛCDM? Planck collaboration has already added massive neutrinos in the vanilla-six parameter model, with Σmν,fiducial = 0.06 eV!

7. April’13 Cosmic Pies ΛCDM + Σmν,fiducial = 0.06 eV ΛCDM + Σmν,fiducial < 0.23 eV

8. Sub-eV massive neutrinos cosmological signatures... @ CMB: Early Integrated Sachs Wolfe effect. The transition from the relativistic to the non relativistic neutrino regime gets imprinted in the decays of the gravitational potentials near the recombination period. Maximal around the first peak. @LSS: Suppress structure formation on scales larger than the free streaming scale when they turn non relativistic. (Bond et al PRL’80) (M. Tegmark)

9. Pre-Planck state of the art of neutrino mass bounds CMB needs HST or SNIa data due to the strong degeneracy between mν𝞶and Ho. WMAP7+SPT09 + HST WMAP7+SPT09 + SNLS WMAP7+SPT09 (Giusarma et al, PRD’12)

10. Pre-Planck state of the art of neutrino mass bounds CMB needs HST or SNIa data due to the strong degeneracy between mν𝞶and Ho. Galaxy clustering data helps enormously as well, either BAO (geometrical) or matter power spectrum (shape) info. WMAP7+LRG DR7 (3D) + HST (Giusarma et al, PRD’12) WMAP7+LRG DR8 (2D) + HST (de Putter et al, APJ’12) WMAP7+LRG DR9 (3D) + BAO + SNLS3 (Zhao et al, 1211.3741) WMAP9+BAO+HST (Hinshaw et al, 1211.3741)

11. Pre-Planck state of the art of neutrino mass bounds Recent (Dec’12-Jan’13) high-l data from SPT’12 and ACT’13......

12. Pre-Planck state of the art of neutrino mass bounds Recent (Dec’12-Jan’13) high-l data from SPT and ACT find a different answer.... (J. Sievers et al, 1301.0824) (Z. Hou et al, 1212.6267)

13. Pre-Planck state of the art of neutrino mass bounds Recent (Dec’12-Jan’13) high-l data from SPT and ACT find a different answer.... (J. Sievers et al, 1301.0824) (Z. Hou et al, 1212.6267)

14. Post-Planck state of the art of neutrino mass 95%CL bounds (Ade et al, 1303.5076) No cosmological evidence for neutrino masses. High-l’s not crucial if constraining only mν. Planck+WP +high-l Planck+WP+BAO + high-l Planck+WP+HST + high-l

15. Euclide-type survey 95%CL neutrino mass bounds 1.5-5σ Detection of the minimum neutrino mass. 2.0-5σ Neutrino hierarchy extraction if weak lensing shear is also considered. Σmν,fiducial = 0.056 eV CMB Planck+shear+galaxies+Clusters (Basse et al, 1304.2321) CMB Planck+shear+galaxies (Hamann et al, JCAP’12) CMB Planck+BAO+Clusters (Carbone et al, JCAP’12)

16. Future 95%CL neutrino mass bounds (Abazajian et al, Astropart.Phys.’11)

17. Neutrinoabundances: Neff = 3.046 standard scenario (after considering non instantaneous neutrino decoupling, flavor oscillations and QED finite temperature corrections). Neff < 3.046 (less neutrinos): Non-standard neutrino couplings, neutrino decays, extremely low reheating temperature models. Neff > 3.046 (more “neutrinos”): Sterile neutrino species (by SBL oscillation data). Also KSVZ axions, extended dark sectors with light species (ADM). (Kopp et al, 1303.3011) (A. Melchiorri et al, JCAP’09)

18. Neff dark radiation species cosmological signatures... @CMB (WMAP, Planck): neutrino perturbations (anisotropic stress, 3rd peak) (Hou et al, 1104.2333) @ CMB damping tail (SPT, ACT, Planck): Higher Neff higher H(z), modifying the photon diffusion scale at recombination increasing the damping at high multipoles. The only degeneracy that still remains is the Neff-Yp (via ne), but Planck data helps in solving it.

19. Pre-Planck state of the art of Neff bounds High-l data from SPT and ACT find (again and again!) a different answer... (Calabrese et al, 1302.1841; Archidiacono et al, 1303.0143; Di Valentino et al, 1301.7343) (J. Sievers et al, 1301.0824) (E. Calabrese et al, 1302.1841) (Z. Hou et al, 1212.6267)

20. Post-Planck state of the art of Neff 95%CL (Ade et al, 1303.5076) Interestingly, Neff >3.046 alleviates the 2.5σtension between the Planck and HST H0’s: These new limits translate into constraints in sterile neutrino, axion and extended dark sector scenarios (Di Bari et al, Mirizzi et al, Di Valentino et al, Brust et al, Boehm et al) Yp degenerate with Neff (CMB damping tail). If both free parameters, Planck+WP+ highL:

21. Current and future Euclid-type 95% CL Neff regions Planck+WP+highL+Yp (Ade et al, 1303.5076) Planck+WP+highL 3+0.046 due to non instantaneous decoupling, QED and flavor mixing } } CMB Planck+shear+galaxies+Clusters (Neff,fid =3.046) (Basse et al, 1304.2321) The small deviation of 0.046 from 3 can be proved with 2σ precision!

22. BBN and Neff BBN theory predicts the abundances of D, 3He, 4He and 7Li which are fixed by t≃180 s. They are observed at late times low metallicity sites with little evolution are “ideal”. Low metallicity extragalactic HII regions. Produced in stars. (E. Aver et al, JCAP’12) (P. A. R. Ade et al, 1303.5076) High z QSO absorption lines. Destroyed in stars. (F. Iocco et al, Phys. Rept’09) Solar system and high metallicity HII galactic regions. 3Henot used for cosmological constraints. Metal poor stars in our galaxy. Destroyed in stars and produced by galactic cosmic ray interactions.

23. BBN and Neff Neff changes the freeze out temperature of weak interactions: Higher expansion rate, higher freeze out temperature, higher 4He fraction: (G. Steigman’12) (P. A. R. Ade et al, 1303.5076)

24. BBN and Neff (G. Steigman’12) Hamann et at, JCAP’11 ΔNeff=2 strongly disfavoured +ξ O(0.1)

25. Neutrino perturbation/clustering parameters

26. Neutrino perturbation/clustering parameters pressure less fluid behaving as clustering dark matter reduces pressure perturbations reduces the amount of damping

27. Neutrinoless double beta decay In some cases in which the ordinary beta decay processes are forbidden energetically, the double beta decay processes might be allowed: Two neutrons are converted into two protons, or viceversa The decay rates are really slow, T~10^19 years, is a second order process in weak interactions. Two neutrino double beta decay processes have been observed experimentally for a number of isotopes. If the lepton number is NOT conserved, the electron neutrino emitted in one of the elementary beta decay processes can be absorbed in another, leading to neutrinoless double beta decay. The decay rates are really small, T~10^23-25 years Such a process would have a clear experimental signature: the sum of the energies of the 2 electrons or positrons should be equal to the total energy release, should be represented by a discrete energy line This decay is only possible if neutrinos have Majorana masses, it violates the lepton number by two units! (assuming no other extensions of the SM)

28. Two neutrino double beta decay Neutrinoless double beta decay Two neutrino double beta decay: Continuous spectrum The 2 electrons or positrons’ energy should be equal to the total energy release, should be represented by a discrete energy line at the end point spectrum

29. Neutrinoless double beta decay The exchanged neutrino in the figure is emitted in a state which is almost totally of right handed helicity, but which contains a small piece, of order m/E, having left handed helicity. When the exchanged neutrino is absorbed, the absorbing left handed current can only absorb its left- handed component without further suppression. Since the left-handed helicity component is O(m/E), the contribution of the neutrino exchange to the neutrinoless double beta decay amplitude is proportional to m. Summing over all the contributions: “effective Majorana neutrino mass”: Sensitive, in principle, to Majorana neutrino phases!

30. In three families we have more Majorana phases: How many? two! Cancellations are really important!

31. Normal hierarchy Inverted hierarchy Degenerate spectrum current 90%CL limits Kamland-ZEN+EXO future 90%CL sensitivities Strumia & Vissani, 2005

32. SZ effect: Inverse Compton scattering of CMB phtons off hight energy electrons located in hot gas in galaxy clusters, and depends on both the thermal energy contained in the ICM as well as on the peculiar velocity of the cluster with respect to the CMB rest frame.