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Theo M. Nieuwenhuizen Institute for Theoretical Physics University of Amsterdam

Do non-relativistic neutrinos constitute the dark matter ? Europhysics Letters 86 (2009) 59001. Theo M. Nieuwenhuizen Institute for Theoretical Physics University of Amsterdam. CSNSM Orsay 23-5-2009. Outline. Introduction: What is dark matter DM.

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Theo M. Nieuwenhuizen Institute for Theoretical Physics University of Amsterdam

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  1. Do non-relativistic neutrinos constitute the dark matter ?Europhysics Letters 86 (2009) 59001 Theo M. Nieuwenhuizen Institute for Theoretical PhysicsUniversity of Amsterdam CSNSM Orsay 23-5-2009

  2. Outline Introduction: What is dark matter DM A modeling in virial equilibrium Comparison to a galaxy supercluster Mass, properties, name of DM particle Nucleosynthesis About virial equilibrium Dark matter condensation on cluster; reionization Conclusion

  3. Dark matter in the Universe • Studied by Jan Hendrik Oort 1932 for our galaxy • Zwicky 1933: for rotation galaxy clusters • V. Rubin 1980: for rotation around galaxies • Needed to explain stability of galaxies • Needed to explain cosmology

  4. Dark matter ring around massive galaxy clusterdetected by Hubble Space Telescope HST

  5. Bullet cluster Two galaxy clusters crossed each other. And so did their dark matter. • White: galaxies and foregrounds • Red: X ray emitted by hot gas • Blue: dark matter inferred from lensing

  6. The two types of dark matter • MACHOs: Massive Astrophysical Compact Halo Objects • Most baryons are dark (non-luminous). • A fraction is in ionized hydrogen clouds. • A fraction is locked up in frozen H-He planets of earth weight. • These planets occur in clumps of 100,000 solar masses. • Some clumps developed into globular star clusters • These clumps act as ideal gas particles around galaxies. • This explains galactic dark matter, its rotation curves. • Too small for detection in Eros II (Dapnia) • WIMPs Weakly Interacting Massive Particles: this talk • The dark matter of galaxy clusters is non-baryonic. • Detected by lensing (galaxies have banana-shape) • About 20-25% of total mass of the Universe. • May or may not be detectable in sky searches (e.g. Edelweiss) • Not MACHOs or WIMPs but MACHOs and WIMPs !!

  7. Abell 1689 galaxy cluster • Nearby z = 0.184 • Total mass • Luminous mass • Baryon poor • Einstein ring

  8. Incomplete Einstein ring at 100/h kpc Abell 1689 center

  9. Abell 1689X-rayemitting gasT=10 keV =1.16 10^8 KDark matterGalaxies Gas

  10. 1689: birth of Montesquieu Charles Louis de Secondat, baron de La Brède et de Montesquieu (1689-1755) • Against slavery • How to prevent despotism? • Trias politica • American, French, (Dutch,…) constitution • woman can head a government,but not be effective as the head of a family

  11. Theory • Assume that DM comes from quantum particles in their common gravitational potential U(r) • Mass m, degeneracy g = 2 (2s+1) #families • Mass density for fermions in equilibrium at T • Gravitational potential U(0)=0 • Poisson eqn (spherical symmetry) • Together they give closed problem for U(r)

  12. Dark matter (x), Galaxies (G) and gas (g) • Hydrostatic equilibrium • Ideal gas laws • Result • Virial equilibrium: equal velocity dispersions M(r) total mass inside r

  13. Dimensionless shape radius, potential thermal length, scale Dark density Poisson eqn dark matter + Galaxies + gas Virial equilibrium: Galaxies gas (ionized H, He, 30% solar metallicity)

  14. Observed quantity in strong and weak lensing Integrated mass along line-of-sight Average in (0, r) Average in (r, r_m) Contrast function From the model

  15. Fit to A1689 lensing data of Tyson and Fischer ApJ 1995Limousin et al, ApJ 2007

  16. The mass of the dark matter particle = number of available modes reduced Hubble parameter small error, 2.0% Previous estimates: keV, MeV, GeV, TeV: excluded Cosmic density of g occupied modes that once were thermal Cosmic matter fraction

  17. What is the dark matter particle? The dark matter fraction matches WMAP5 for g=12 (anti) neutrinos, left+right handed, 3 families 2*2*3=12 mass = 1.455 eV Not: axions, gravitinos, neutralinos, X-inos (early decouplers have small occupation) Thermal length visible to the eye Temperature is low Typical speed is non-relativistic, v = 490 km/s Local density can be enormous: in Abell center: one billion in a few cc

  18. The biggest quantum structure # neutrinos per (thermal wavelength)^3 per degree of freedom N=1: quantum-to-classical crossover at r = 505 kpc = 1.6 million light year d = 2r = 3.2 million light year That is pretty big … Baryons are poor tracers of dark matter density, even though they do trace the enclosed mass

  19. Temperature of gas: 10 keV=10^8 K Virial T of alpha-particles Log(Mass) Virial equilibrium assumed; only amplitude adjusted Log(r/kpc) Cluster radiates like a star. Radiated energy supplied by contraction.Radiation helps to keep virial equilibrium.

  20. Right handed neutrinos and nucleosynthesis • Extra neutrino ``families’’ • Extra matter causes enhanced expansion • Faster expansion: too few neutron decays, too much He-4 • Neutrino asymmetry: more neutrinos than anti-neutrinos • Thus more reactions for neutron decay • These effects can compensate each other • So nucleosynthesis can accommodate right-handed neutrinos

  21. Effect on data Steigman IJMP E, 2005 =0= ==0== ===0===== Adjusting He-4 to WMAP

  22. Why virial equilibrium? • Lynden Bell: violent relaxation. • Relaxation in time-dependent potential exchanges energy of a given particle with the gravitational energy of the whole cluster • Iff phase space density uniform, then Fermi-Dirac distribution • Iff not, it is probably a “good” approximation. • X-ray radiation helps to maintain the virial state

  23. CDM or HDM? • Cold Dark Matter: it is already clumped at decoupling z=1100 • But neutrinos are free streaming until trapped by galaxy cluster • Crossover when Newton force matches Hubble force • Free streaming • At cluster center • They match at crossover: Voids loose neutrinos at z=28, T=77 L, age 120 Myr. • This heats the intracluster gas up to 10 keV, so it reionizes • Hot Dark Matter is the proper paradigm; Agrees with gravito-hydrodynamics

  24. What about galactic dark matter? • Proto globolar clusters: Clumps of H-He planets, of weight 1 million M_sun each, act as ideal gas particles • In virial equilibrium due to mutual collisions • polylog linearizes • gets absorbed by a shift: unique shape of profile • Virial speed

  25. Galaxy rotation curves

  26. Summary • Observed DM of Abell supercluster explained by thermal fermions. • Fitting with global dark matter: g=12, m=1.45 eV • Corresponds to neutrinos+antineutrinos, left+right, 3 families • Free flow into potential well occurs at z = 28. Causes reionization • Neutrino mass should be seen in Katrin expt (2012-2012+0.0001) • Dark matter particle was not (should not) be observed in searches ADMX, ANAIS, ArDM, ATIC, BPRS, CAST, CDMS,CLEAN, CRESST, CUORE, CYGNUS, DAMA, DEEP, DRIFT, EDELWEISS,ELEGANTS, EURECA, GENIUS, GERDA, GEDEON, GLAST, HDMS, IGEX, KIMS,LEP, LHC, LIBRA, LUX, NAIAD, ORPHEUS, PAMELA, PICASSO, ROSEBUD,SIGN, SIMPLE, UKDM, XENON, XMASS, ZEPLIN. • CDM is out. Neutrinos are hot.

  27. Psalm 118:22 The stone which the builders refused is become the head stone of the corner

  28. KArlsruhe TRItium Neutrino Experiments

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