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T he dark universe

T he dark universe. P. Binétruy AstroParticule et Cosmologie, Paris. Second Sino-French Workshop, Beijing, 28 August 2006. The twentieth century legacy. Two very successful theories :. General relativity. A single equation, Einstein’s equation, successfully predicts

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T he dark universe

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  1. The dark universe P. Binétruy AstroParticule et Cosmologie, Paris Second Sino-French Workshop, Beijing, 28 August 2006

  2. The twentieth century legacy

  3. Two very successful theories : • General relativity A single equation, Einstein’s equation, successfully predicts tiny deviations from classical physics and describes the universe at large as well as its evolution. R - (R/2) g = 8GN T geometry matter

  4. Quantum theory Describes nature at the level of the molecule, the atom, the nucleus, the nucleons, the quarks and the electrons .

  5. Difficult to reconcile general relativity with the quantum theory: bestillustration is the vacuum problem ( cosmological constant pb) Classically, the energy of the fundamental state (vacuum) is not measurable. Only differences of energy are (e.g. Casimir effect). Einstein equations: R - R g/2 = 8G T geometry energy Hence geometry may provide a way to measure absolute energies i.e. vacuum energy:

  6. R - R g/2 = 8G T + 8G < T > vacuum energy similar to the cosmological term introduced by Einstein : R - R g/2 = 8G T +  g Such a term tends to accelerate the expansion of the universe : H2 = 8 G ( + ) /3 - k/a2     / (8 G ) curvature term Present observations (k=0,  < ) yield   ~H02 / 8 G ~ (10-3 eV)4

  7. Computing the vacuum energy associated with the SM vac ~ MW4 ~ (1011 eV)4to be compared with  ~ (10-3 eV)4 The electroweak scale MW ( lW = 10-18 m) or the Planck scale mP = √ hc/8GN = 2.4 1018 GeV ( lP = 10-34 m) obviously do not provide the size of the Universe. Horizon scale : H0 -1 =1026 m Critical energy density c = 3H02 /8  GN  c4 c = 10-3 eV

  8. From the experimental and observational point of view, • exploration of the infinitely small electron, neutrino; up and down quarks make the proton/neutron Why do we need a muon?

  9. exploration of the infinitely large First only detecting visible light, then all electromagnetic spectrum

  10. But also particles… Cosmic rays Neutrinos And other types of waves … gravitational waves

  11. Also indirect ways allow to identify new components of the Universe First example: rotation curves of galaxies  dark matter e.g. spiral galaxies astro-ph/9506004

  12. Also indirect ways allow to detect new components of the Universe First example: rotation curves of galaxies  dark matter e.g. spiral galaxies luminous matter astro-ph/9506004

  13. Also indirect ways allow to detect new components of the Universe First example: rotation curves of galaxies  dark matter e.g. spiral galaxies luminous matter exponential halo astro-ph/9506004

  14. Also indirect ways allow to detect new components of the Universe First example: rotation curves of galaxies  dark matter e.g. spiral galaxies luminous matter exponential halo total contribution astro-ph/9506004

  15. also detected through gravitational lensing

  16. Second example: measuring cosmic distances with supernovae explosions  dark energy

  17. Supernovae of type Ia magnitude versus redshift mB = 5 log(H0dL) + M - 5 log H0 + 25 1-q0 luminosity distance dL = lH0 z ( 1 + ------- z + …) 2 q0 deceleration parameter q0 = M /2 -  for a-CDM model M  M / c    / c

  18. Unknown component of equation of state p = w , w < 0 (cosmological constant w= -1) Need for dark matter from the study of the universe at cosmological distance scales

  19. Why are we so excited about this field? Theoretical ideas Experiments and observations

  20. Theoretical ideas • We have a good candidate for the unification of gravity • with quantum theory : string theory. Modifies drastically our view of spacetime : hopes to solve the vacuum energy problem . But no clear solution in view! • Theories beyond the Standard Model provide many new fields : Dark matter  New fermions or vector fields Dark energy  New scalar fields

  21. Models for dark matter Modification of gravity Dark matter baryonic non-baryonic MOND TeVeS Exotic particles Primordial Black holes Extra dimensions Clumped Hydrogen MACHO dust nonthermal thermal Wimpzillas axion SuperWIMPS Light  WIMPS

  22. Experiments and observations • present

  23. mh2 = 0.12 mh2 = 0.13 mh2 = 0.14 Acoustic series in P(k) becomes a single peak in (r) Pure CDM model has no peak. Baryon Acoustic Oscillations Acoustic oscillations are seen in the CMB . Look for the the same waves in the galaxy correlations. CDM with baryons is a good fit: 2= 16.1 with 17 dof.Pure CDM rejected at 2= 11.7

  24. Baryon oscillations are really discriminating for dark energy Blanchard et al 2003 Blanchard, Douspis, Rowan-Robinson, Sarkar 2005 CDM M = 0.88, v=0.12, H0 = 46 SNe ignored. cannot accommodate =0 with baryon acoustic peak.

  25. Confidence Contours Tot=1 w=-1 BAO: Baryon Acoustic Oscillations (Eisenstein et al 2005, SDSS) 68.3, 95.5 et 99.7% CL See R. Pain’s talk

  26. WDE(z)

  27. future

  28. Dark matter See G. Gerbier’s talk

  29. Indirect detection Through annihilation of wimps accumulated in the center of massive objects : Earth, Sun, galactic center. HESS, GLAST, AMS, ANTARES/AMANDA/KM3NET, ….

  30. 3.5 Position: FWHM: 511.06 ± 0.18 keV 2.95 ± 0.5 keV 3.0 2.5 2.0 Intensity (10-4 photon cm-2 s-1 sr-1) 1.5 1.0 0.5 0,0 -0.5 500 505 510 515 520 525 Energy (keV) Are we heading for surprises? 0 20 20 FWHM: 9° (-3° / +7°) • Difficult to understand if : • Decay of massive particles • Positrons injected by compact jet sources • +decay of radioactive nuclei released by novae •  +decay of 56Co released by thermonuclear (type Ia) supernovae • More adequate : •  +decay of 56Co released by gravitational supernovae/hypernovae • Annihilation of a new form of dark matter, scalar and light • (Boehm, Hooper, Silk, Cassé & Paul, PRL 92, 101301) 10 0 Galactic latitude (degrees) -10 -20 INTEGRAL/SPI spectrum of the Galactic center region The intensity of the 511 keV line emission (10-3photons s-1)implies the annihilation of ~1043positrons per second in the Galactic bulge.

  31. Dark energy Future programs both in space (SNAP/JDEM/DUNE) and on the ground (SDSS, LSST, SKA/FAST,…)

  32. Expected Planck performance on dark energy equation of state w = w0 + w1 z Seo & Eisenstein 2003 Huterer & Turner 2001

  33. Other standard candles • Gamma ray bursts Determine the luminosity through a relation between the collimation corrected energy E and the peak energy cf. SVOM/ECLAIRs • coalescence of supermassive black holes

  34. Inspiral phase (m1 m2)3/5 Key parameter : chirp mass M = (1+z) (z) (m1 + m2)1/5

  35. Inspiral phase (m1 m2)3/5 Key parameter : chirp mass M = (1+z) (z) (m1 + m2)1/5 Amplitude of the gravitational wave: frequency f(t) = d/2dt M(z)5/3 f(t)2/3 h(t) = F (angles) cos (t) dL Luminosity distance

  36. Inspiral phase (m1 m2)3/5 Key parameter : chirp mass M = (1+z) (z) (m1 + m2)1/5 Amplitude of the gravitational wave: M(z)5/3 f(t)2/3 h(t) = F (angles) cos (t) dL Luminosity distance poorly known in the case of LISA 10 arcmin 1 Hz ~ SNR fGW

  37. z = 1 , m1 = 105 M, m2 = 6.105 M 3° (arcminutes) 5% Holz & Hughes dL/dL

  38. Using the electromagnetic counterpart Allows both a measure of the direction and of the redshift 0.5% Holz and Hughes dL/dL Limited by weak gravitational lensing?

  39. My own theoretical prejudices : • dark matter: WIMP connected with the electroweak • symmetry breaking issue • dark energy : back reaction models

  40. Connecting the naturalness of the electroweak scale with the existence of WIMPs STEP 1 : naturalness 3mt2 22v2 6MW2 + 3MZ2 8 2v2 3mh2 8 2v2 mh2 = t2 - g2 - h2 v = 250 GeV |mh2 | < mh2 Naturalness condition : Introduce new physics at t or raise mh to 400 GeV range

  41. STEP 2 : stable particles in the MEW mass range E New local symmetry Lightest odd-parity particle (LOP) is stable New discrete symmetry Standard Model fermions New fields

  42. Example 1: low energy SUSY E R symmetry Stable LSP R parity Standard Model fermions Supersymmetric partners

  43. Example 2: extra compact dimension (orbifold) E A(m) + B(n) C(p) + D(q) m+n=p+q 5-dimensional Lorentz invariance Stable lightest KK mode (B(1)) (-)n KK parity Standard Model fermions KK modes

  44. Introduce a second Higgs doublet H2 which is not coupled to fermions (symmetry H2  -H2) Example 3: Inert Doublet Model E ? Stable Lightest Inert Particle H2 -H2 Standard Model fermions Inert scalars Barbieri, Hall, Rychkov, hep-ph/0603188

  45. STEP 3 : compute relic density 25 109 GeV-1 xf LOP h02 ~ g*1/2 MP < ann v> Number of deg. of freedom at time of decoupling  LOP h02 ~ 1 LOP mass ~ MEW < ann v>~  EW/MEW2 to be compared with DM h02 = 0.112  0.009

  46. mSUGRA  tan=5 tan=35 Y. Mambrini,, E. Nezri ~ Co-annihilation0 Focus point (WW,ZZ) Near-resonant s-channel anni- hilation through heavy Higgs states A and H (b b, + -) -  tan=50

  47. STEP 4 : search for the LOP at LHC As the LSP, missing energy signal

  48. STEP 5: search LOP through direct detection e.g. minimal sugra model

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