Relic Neutrinos, thermal axions and cosmology in early 2014 Elena Giusarma arXiv: Based on work in collaboration with: E. Di Valentino, M. Lattanzi, A. Melchiorri, O. Mena

Outline  Cosmological neutrino mass implications  Existence of extra hot relic components as dark radiation relics, steriles neutrino species and/or thermal axions  Cosmological data used in our numerical analysis  Neutrino mass bounds in different cosmological scenarios  Impact of BICEP2 measurements for the relativisitc degrees of freedom and neutrino masses  Conclusions

In the stanard cosmology hot, thermal relics are identified with the three light, active neutrino flavours of the Standard Model of elementary particles. Neutrino masses have an impact in the different cosmological observable: CMB: a) Early Integrated Sachs Wolfe effect. The transition from the relativistic to the non relativistic neutrino regime affect the decays of the gravitational potentials at decoupling period (especially near the first acoustic peak). b) Suppression of lensing potential (with Planck). LSS: Suppression of structure formation on scales smaller than the free streaming scale when neutrinos turn non relativistic. Planck+WMAP 9-polarization data: Planck+WMAP 9-polarization +HST data: (M. Tegmark) Planck+WMAP 9-polarization +HST+BAO data: (Ade et al ‘13 Planck Collaboration ) ∑m ν <1.11 eV at 95% CL ∑m ν <0.21 eV at 95% CL ∑m ν <0.26 eV at 95% CL

 Massless sterile neutrino species: e.g. extra degrees of freedom produced by the annihilation of asymmetric Dark Matter  Extra steriles massive neutrino species: motivated by the so-called neutrino oscillation anomalies  Thermal axion: motivated by the strong CP problem Candidates for extra hot relic components These extra species Have an associated free streaming scales, reducing the growth of matter fluctuations at small scales Contribute to the effective number of relativistic degrees of freedom N eff N eff = ΔN eff

Data1 CMB : o Planck temperature anisotropies, including lensing potential o WMAP 9-year polarization o ACT and SPT measurements at small scales o B-mode polarization measurements from BICEP2 Large scale structure: o SDSS Data Release 7 o 6-degree Field Galaxy Survey o New BOSS Data Release 11 o WiggleZ survey (the full shape of the matter power spectrum and the geometrical BAO information ) Baryon Acoustic Oscillation (BAO) data

Data2 σ 8 measurements: o CFHTLens survey o Planck Sunyaev-Zeldovich cluster catalog Big Bang Nucleosynthesis light elements abundance : Hubble constant measurements: o Hubble Space Telescope

Cosmological parameters 1.ΛCDM model with 3 massive neutrino species: Extra Radiation Component at the BBN period 2. ΛCDM model with 3 massive neutrino species and thermal axion: 3. ΛCDM model with 3 massive neutrino and ΔN eff massless dark radiation species:

4. ΛCDM model with 3 active massive neutrinos plus ΔN eff massive steriles neutrino species: Cosmological parameters T s, T ν current temperature of the sterile and active neutrino species. m s real mass of sterile neutrino species. UNIFORM PRIORS for the cosmological parameters: N eff priors refer to the massless (massive) case ΔN eff =N eff -3.46=(T s /T ν ) 4

Main Results(1) 68% and 95% CL allowed regions in the (∑m ν, H 0 ) and in the (∑m ν, σ 8 ) plane The allowed neutrino mass regions are displaced after considering Planck cluster data and a non zero value on ∑m ν is favoured. 1.ΛCDM model with 3 massive neutrino species : CMB+DR11+BAO+HST: CMB+DR11+BAO+HST+SZ Cluster: CMB+DR11+BAO+HST+CFHTLens: The addition of the constraints on σ 8 and Ω m from the CFHTLens survey displaces the bounds on the neutrino mass to higher values. Giusarma et al arXiv:

Main Results(2) 68% and 95% CL allowed regions in the (∑m ν, m a ) plane for different combinations of data Only with Planck SZ cluster data a non zero value of axion mass is favoured at the 2.2σ No evidence for non-zero neutrino masses nor for non-zero axion mass. 2. ΛCDM model with 3 massive neutrino species and thermal axion: CMB+DR11+WZ+HST+SZ Cluster: CMB+DR11+BAO+HST+SZ Cluster: Evidence for neutrino mass of 0.2 eV at 3 σ on only for one case Giusarma et al arXiv:

Main Results(3) 68% and 95% CL allowed regions in the (∑m ν, N eff ) and in the (N eff, H 0 ) plane The prior on the value of the Hubble constant from HST increases the mean value on N eff 3. ΛCDM model with 3 massive neutrino and ΔN eff =N eff massless dark radiation species: CMB+DR11+WZ+HST+BBN (Cooke et al.): NO EVIDENCE FOR N eff >3 CMB+DR11+WZ+HST+BBN (Iocco et al.): EVIDENCE FOR N eff >3 Giusarma et al arXiv:

Main Results(4) 4. ΛCDM model with 3 active massive neutrinos plus ΔN eff massive steriles neutrino species: 68% and 95% CL allowed regions in the (∑m ν, N eff ) and in the (∑m ν, m s eff ) plane The bound on N eff (∑m ν ) is slightly larger (more stringent) than in massless sterile neutrino scenario due to the degeneracy with m s eff NO SIGNIFICANT PREFERENCE FOR N eff >3 CMB+DR11+WZ+HST+BBN(Cooke et al.): CMB+DR11+WZ+HST+BBN(Iocco et al.): SIGNIFICANT PREFERENCE FOR N ef f >3 Giusarma et al arXiv:

BICEP2 measurem en t s BICEP2: detection at about 5.9 σ for B-mode polarization on large scales at 68% CL Ade et al ‘14 BICEP2 Collaboration Apparent tension with Planck+WP limit: r<0.11 at 95% cl

What is the impact of BICEP2 measurements on neutrino properties? ΛCDM +r model with 1 massive neutrino (0.06 eV) and ΔN eff =N eff massless dark radiation species: ΛCDM +r model with 3 massive neutrino: Evidence for N eff >3 but no indication for neutrino masses Extra relativistic component seems to solve the tension between the Planck and BICEP2 experiments on r Giusarma et al arXiv: r = 0.15±0.04 at 68% CL

Conclusions Constraints on the masses of the different thermal relics in different scenarios using the most recent comological data In the minimal three active massive neutrino scenario we found that CFHTLens survey displaces the bound on neutrino masses to higher value. Planck cluster data favours a non zero value on ∑m ν of about 0.3 eV at 4σ. In the scenario with thermal axions and active massive neutrino species we found that only considering the Planck SZ cluster data plus CMB+DR11+ BAO+HST there exists a prefernce for axion mass of 0.6 eV at the obout 2.2σ and only combining Planck SZ cluster data with CMB+DR11+ WZ+HST there is an evidence for neutrino mass of 0.2 eV at about 3σ. In the scenario with massive neutrinos and ΔN eff dark radiation species the bounds on ∑m ν are less stringent. BBN constraints reduce both mean value and the errors ok N eff significantly. Considering B-mode polarization measurements by BICEP2 experiment +Planck+WP data, we found that an extra realivistic component could solve the tension between the two experiments on the amplitude of tensor mode.