1. Constraining DM scenarios with CMB Fabio Iocco Institut d’Astrophysique de Paris Institut de Physique Theorique, CEA/Saclay In collaboration with: G. Bertone, M. Cirelli, S. Galli, A. Melchiorri, P. Panci RPP, Lyon, 26/01/10

2. The Pamela(/Fermi/ATIC) saga (or “buzz”, see talk by J. Lavalle) IF intepreted as DM: High annih cross-section ~10 -24 -10 -21 cm 3 /s Forget about thermal decoupling WIMP miracle Unless = (v) DM decoupling:  ~1 Recombination:  ~10 -8 Small halos:   10 -4 Milky Way:  ~10 -4 By courtesy of M. Cirelli “Sommerfeld” enhancement fulfills the requirements (higher masses preferred) E [GeV] e - + e + e + fraction

3. DM annihilation and the IGM   e  p W primary HE shower heating and ionization Courtesy of T. Slatyer GeV scale keV scale

4. Self-annihilating DM and the IGM The smooth DM component annihilates with a rate (per volume) depositing energy in the gas (IGM) at a rate more about “ f ” later Main effect of injected energy: heating and ionization of the IGM Evolution of free electron fraction, x e The only DM parameter is [Galli, FI, Bertone, Melchiorri `09]

5. Self-annihilating DM and the CMB DM annihilation indirect, SZ by “additional” e - z>1000 there are many e - no effects Energy injection is small Letting p ann free parameter [Galli, FI et al. `09] Modifying TT, TE, EE with additional e - (by DM annih)

6. A little more about “ f ” (coupling DM induced shower to IGM) “ f ” is DM model-dependent: type of secondaries is important! Photoionization, IC scattering, pair production (on CMB  and matter),  scattering [Slatyer et al. `09] “Opacity window” of the Universe

7. Evaluating “ f ” All channels, all secondaries, redshift dependence [Slatyer et al. 09] leptons quarks XDM => e  XDM =>  Branching ratio of DM annihilation essential for determining absorption Little reminder: Pamela is leptophilic

8. Structure formation “boosts” DM annihilation Structure formation starts at z ~ 150 with minihalos of Earth mass 10 -6 Msun Smooth component Structure component Structure formation history (Press-Schechter / Sheth-Tormen) DM density halo profile Burkert / Einasto / NFW

9. Structure boost: parameter dependence M min =M fs (?) C vir (M) = ? [Huetzi et al. 09][Pieri et al 08] [Cirelli, FI, Panci `09]

10. Transparency of the Universe & structure formation HE shower gets absorbed at high z Structure formation takes place in a late Universe [Slatyer, et al..`09] [Cirelli, FI, Panci `09]

11. Neutral: Ly-  absorber z Ionized: Ly-  free to pass by z ~ 6 A quick view on “Reionization”  = free electrons

12. Electron optical depth  Measured with CMB polarization WMAP 5 value Integrated quantity!

13.  constraints (annihilation from structures can overproduce free e - ) To be integrated! [CIP `09] In this models: no astrophysical sources (z > 6) Extra-conservative bounds!

14. Constraining DM with CMB [Galli et al. 09] + [Slatyer et al. 09]

15. Constraining SE with CMB [Galli et al. 09] z r =1000,  10 -8 Sommerfeld saturated Yukawa potential a benchmark model Sommerfeld enhancement

16. Temperature constraints! [CIP 09] “Exotic heating”: DM, after coupled f 1/3 heat, 1/3 ioniz. 1/3 Ly- 

17. Watching negative: gammas [Profumo & Jeltema 09] Mainly IC photons z band breakup: locally dominated e + e - boost IC

18. Combining the constraints [Hurtzi et al 09]      channel NFW profile [CIP 09] gammas +   + IGM temperature

19. Down to thermal cross-section! z [CIP `09] [Galli, FI et al. `09] conservative bounds, no astrophysics z > 6

20. Concluding It is possible to use Early Universe astrophysical observables to constrain DM properties Self-annihilating DM can inject enough energy (free electrons) to modify the cross correlation CMB spectra! The detectability of a DM annihilation in the CMB signal is DM model dependent (annihilation channel) Would you ever believe we have found DM if I told you there is an (even strong) anomaly in the TE CMB spectrum? Signal comes from smooth DM density field (can get rid of structure formation uncertainties!)

21. ≤ 10 -21 cm 3 /s 5.1x10 -4 ≤ Z ≤ 2x10 6 [McDonald, Scherrer, Walker ‘02] [Zavala, Volgersberger, White ‘09] Looser constraint than from anisotropies