Dark matter: evidence and candidates

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1 .... Dark matter: evidence and candidates Zhao-Huan Yu ( 余钊焕 ) Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, CAS March 14, 2014 Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

2 .... Dark matter (DM) in the Universe Dark matter exists at various scales in the Universe. (galaxies, clusters, large scale structures, cosmological scale) However, its microscopic property remains unknown. Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

3 .... Coma cluster ( 后发座星系团 ) 大熊小狮狮子猎犬后发室女北冕牧夫 Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

4 .... Coma cluster ( 后发座星系团 ) 大熊小狮狮子猎犬后发室女北冕牧夫 Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

5 .... Coma cluster ( 后发座星系团 ) 大熊小狮狮子 In 1933, Fritz Zwicky found that the velocity dispersion of galaxies in the Coma cluster was far too large to be supported by the luminous matter. Mass-to-light ratio Υ Coma 260Υ [Kent & Gunn, 1982] 北冕猎犬牧夫后发室女 Typical spiral galaxy: O(10)Υ Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

6 Astrophysical evidences Spiral galaxies: rotation curves In the 1970s, Vera Rubin and her collaborators measured the rotation curves of spiral galaxies and also found evidence for non-luminous matter. Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

7 Astrophysical evidences Spiral galaxies: rotation curves In the 1970s, Vera Rubin and her collaborators measured the rotation curves of spiral galaxies and also found evidence for non-luminous matter. Triangulum galaxy M33 M33 dark matter halo stellar disk gas [Corbelli & Salucci, astro-ph/ ] Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

and also found evidence for non-luminous matter.

8 Astrophysical evidences Spiral galaxies: rotation curves In the 1970s, Vera Rubin and her collaborators measured the rotation curves of spiral galaxies and also found evidence for non-luminous matter. Triangulum galaxy M33 According to Newton s law, the relation between the rotation velocity v and the mass M (r) within radius r should be. v2 GN M (r) = r2. r M33 dark matter halo stellar disk gas M (r) = constant v r 1/2 M (r) r Zhao-Huan Yu (IHEP) v = constant [Corbelli & Salucci, astro-ph/ ] Dark matter: evidence and candidates Mar / 23

9 .... How can we explain an anomalous phenomenon? Unexpected movement of Uranus Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

10 .... How can we explain an anomalous phenomenon? Unexpected movement of Uranus Perturbed by Neptune (discovered in 1846) Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

11 .... How can we explain an anomalous phenomenon? Unexpected movement of Uranus Perturbed by Neptune (discovered in 1846) Search for new objects/substances responsible for it! Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

12 .... How can we explain an anomalous phenomenon? Unexpected movement of Uranus Perturbed by Neptune (discovered in 1846) Search for new objects/substances responsible for it! Anomalous perihelion precession of Mercury Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

13 .... How can we explain an anomalous phenomenon? Unexpected movement of Uranus Perturbed by Neptune (discovered in 1846) Search for new objects/substances responsible for it! Anomalous perihelion precession of Mercury Update Newtonian mechanics to general relativity Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

Anomalous perihelion precession of Mercury

14 .... How can we explain an anomalous phenomenon? Unexpected movement of Uranus Perturbed by Neptune (discovered in 1846) Search for new objects/substances responsible for it! Anomalous perihelion precession of Mercury Update Newtonian mechanics to general relativity Modify known physical laws! Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

15 .... How about the anomalous phenomena here? Modify physical laws MOdified Newtonian Dynamics (MOND) [Milgrom, ApJ, 1983] Difficult to coherently explain data at all scales with one model. Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

16 .... How about the anomalous phenomena here? Modify physical laws MOdified Newtonian Dynamics (MOND) [Milgrom, ApJ, 1983] Difficult to coherently explain data at all scales with one model. Consider new objects MAssive Compact Halo Objects (MACHOs) (baryonic dark matter: brown dwarfs, jupiters, stellar black-hole remnants, white dwarfs, neutron stars,...) MACHO fraction in the Galactic dark matter halo: < 8% (95% C.L.) [EROS-2 coll., astro-ph/ ] Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

17 .... How about the anomalous phenomena here? Modify physical laws MOdified Newtonian Dynamics (MOND) [Milgrom, ApJ, 1983] Difficult to coherently explain data at all scales with one model. Consider new objects MAssive Compact Halo Objects (MACHOs) (baryonic dark matter: brown dwarfs, jupiters, stellar black-hole remnants, white dwarfs, neutron stars,...) MACHO fraction in the Galactic dark matter halo: < 8% (95% C.L.) [EROS-2 coll., astro-ph/ ] Consider new substances Nonbaryonic Dark Matter (not constituted by baryons) Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

.... Bullet cluster: disfavor MOND Fluid-like X-ray emitting plasma (visible matter) Mass distribution observed by weak gravitational lensing (DM dominated) An 8σ significance spatial offset of the

18 .... Bullet cluster: disfavor MOND Fluid-like X-ray emitting plasma (visible matter) Mass distribution observed by weak gravitational lensing (DM dominated) An 8σ significance spatial offset of the center of the total mass from the center of the baryonic mass peaks cannot be explained with an alteration of the gravitational force law. [Clowe et al., astro-ph/ ] Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

19 .... Big bang theory According to the big bang theory, 13.8 billion years ago, the Universe was extremely hot and dense. Everything was in thermal equilibrium and interacted with each other. As it expanded, the Universe cooled down. Its constituents decoupled from the thermal bath one by one. Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

20 .... Structure formation: hot, cold, and warm dark matter Small initial fluctuations + Gravitational instability Decoupled matter generates cosmological structures Baryonic matter decoupled too late. Only baryonic matter Galaxies would not be formed! Needs nonbaryonic dark matter which decoupled much earlier Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

21 .... Structure formation: hot, cold, and warm dark matter Small initial fluctuations + Gravitational instability Decoupled matter generates cosmological structures Baryonic matter decoupled too late. Only baryonic matter Galaxies would not be formed! Needs nonbaryonic dark matter which decoupled much earlier Hot dark matter (such as neutrinos): relativistic when it decoupled structure forms by fragmentation (top-down) Cold dark matter (CDM): nonrelativistic when it decoupled structure forms hierarchically (bottom-up) Galaxies are older than clusters Favors cold dark matter theory Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

22 .... Structure formation: hot, cold, and warm dark matter Small initial fluctuations + Gravitational instability Decoupled matter generates cosmological structures Baryonic matter decoupled too late. Only baryonic matter Galaxies would not be formed! Needs nonbaryonic dark matter which decoupled much earlier Hot dark matter (such as neutrinos): relativistic when it decoupled structure forms by fragmentation (top-down) Cold dark matter (CDM): nonrelativistic when it decoupled structure forms hierarchically (bottom-up) Galaxies are older than clusters Favors cold dark matter theory Milky Way dwarf satellites: 20 (observed) vs. 500 (CDM predicted) Missing satellites problem Warm dark matter? Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

23 .... CMB Standard cosmology: ΛCDM model In the ΛCDM model, the Universe contains a cosmological constant Λ (dark energy) and cold dark matter (CDM). The evolution of the Universe is governed by the Friedmann equation:. k. H 2 R 2 = Ω Λ + Ω m + Ω r No Big Bang SNe 0.5 BAO Flat [WMAP Science Team] [Kowalski et al., ] Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

.... Cosmic microwave background (CMB). t 380 000 yr, T 3000 K Electrons + protons hydrogen atoms. Photons decoupled cools down.. Today, 2.

24 .... Cosmic microwave background (CMB). t yr, T 3000 K Electrons + protons hydrogen atoms. Photons decoupled cools down.. Today, 2.7 K microwave background Dl[µK 2 ] CMB anisotropies encode the information from the early Universe. The shape of anisotropy power spectrum depends on cosmological parameters, such as Ω Λ, Ω m, Ω b, Angular scale Planck Coll Multipole moment, l WMAP Dark matter 22.7% 26.8% Ordinary matter 4.5% 4.9% Dark energy 72.8% 68.3% Planck Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

25 .... Big bang nucleosynthesis (BBN): t 1 sec 1 hour log( Y P ) -3 log[ B (g cm )] log( N A / N H ) min 3 min 1 h 1/2 = 10.6 min = = 3 B 3 He 4 He 2 D 3 T 7 Li 7 Be T (MeV) [Kolb & Turner, The Early Universe] n Y p D 0.24 H He D/H p 3 He/H p Baryon density Ω b h BBN CMB Primordial abundances of light elements Baryon density Ω b (consistent with CMB observations) The majority of matter is nonbaryonic Li/H p Baryon-to-photon ratio η [Cyburt et al., ] Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

26 .... Inferred properties of dark matter Dark (electrically neutral): no light emitted from it Nonbaryonic: BBN & CMB observations Long lived: survived from early eras of the Universe to now Colorless: otherwise, it would bind with nuclei Cold: structure formation theory Abundance: more than 80% of all matter in the Universe ρ DM 0.4 GeV/cm 3 near the earth Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

27 .... Standard model (SM) of particle physics SU(3) C SU(2) L U(1) Y gauge symmetry Spontaneous symmetry breaking of the Higgs field Electroweak symmetry breaking & generating fermion masses Leptons e μ τ ν ν ν e μ τ q Quarks γ W Z g Photon Weak Gluons Bosons H Higgs Boson Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

28 .... Are there dark matter candidates in the standard model? Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

29 .... Are there dark matter candidates in the standard model? Nonbaryonic Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

30 .... Are there dark matter candidates in the standard model? Nonbaryonic Colorless Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

31 .... Are there dark matter candidates in the standard model? Nonbaryonic Colorless Electrically neutral Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

32 .... Are there dark matter candidates in the standard model? Nonbaryonic Colorless Electrically neutral Long lived Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

33 .... Are there dark matter candidates in the standard model? Nonbaryonic Colorless Electrically neutral Long lived Massive Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

34 .... Are there dark matter candidates in the standard model? Nonbaryonic Colorless Electrically neutral Long lived Massive Hot DM: neutrinos Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

35 .... Are there dark matter candidates in the standard model? Nonbaryonic Colorless Electrically neutral Long lived Massive Hot DM: neutrinos Cold DM: none Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

36 .... WIMP miracle The relic density of dark matter can be calculated by the Boltzmann equation: ṅ χ + 3Hn χ = σ ann v [n 2 χ (neq χ )2 ] Ω χ h cm 3 s 1 σann v [Feng, arxiv: ] Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

37 .... WIMP miracle The relic density of dark matter can be calculated by the Boltzmann equation: ṅ χ + 3Hn χ = σ ann v [n 2 χ (neq χ )2 ] Ω χ h cm 3 s 1 σann v Observed relic density σann v O(10 26 ) cm 3 s 1 Typical value of weak interactions Weakly interacting massive particles (WIMPs) are wonderful candidates [Feng, arxiv: ] Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

38 .... Problem of the standard model A 125 GeV Higgs boson has been discovered at the LHC [ATLAS Coll., ; CMS Coll., ] In the standard model, the quantum correction of the Higgs boson mass m 2 H suffers from the quadratic divergence Hierarchy problem New physics at the TeV scale (Supersymmetry, extra dimensions, little Higgs,...) New physics models often involve candidates for WIMP dark matter Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

39 .... Supersymmetry (SUSY).. A symmetry between fermions and bosons e, µ, τ leptons sleptons ẽ, µ, τ ν e, ν µ, ν τ neutrinos sneutrinos ν e, ν µ, ν τ d, u, s, c, b, t quarks squarks d, ũ, s, c, b, t g gluon gluino g W ±, H ± charged bosons charginos χ ± 1, χ± 2 B, W 3, H 0 1, H0 2 neutral bosons neutralinos χ 0 1, χ0 2, χ0 3, χ0 4 Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

40 .... Supersymmetry (SUSY).. A symmetry between fermions and bosons e, µ, τ leptons sleptons ẽ, µ, τ ν e, ν µ, ν τ neutrinos sneutrinos ν e, ν µ, ν τ d, u, s, c, b, t quarks squarks d, ũ, s, c, b, t g gluon gluino g W ±, H ± charged bosons charginos χ ± 1, χ± 2 B, W 3, H 0 1, H0 2 neutral bosons neutralinos χ 0 1, χ0 2, χ0 3, χ0 4 Not to violate baryon number B or lepton number L R-parity conserved SUSY [P R = ( 1) 3(B L)+2s ] The lightest SUSY particle (LSP) is stable An attractive candidate for non-baryonic dark matter Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

41 .... SUSY particles Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

42 .... SUSY particles Nonbaryonic Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

43 .... SUSY particles Nonbaryonic Colorless Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

44 .... SUSY particles Nonbaryonic Colorless Electrically neutral Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

45 .... SUSY particles Nonbaryonic Colorless Electrically neutral Long lived Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

46 .... SUSY particles Nonbaryonic Colorless Electrically neutral Long lived Not excluded by experiment Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

47 .... SUSY particles Nonbaryonic Colorless Electrically neutral Long lived Not excluded by experiment Cold DM: χ 0 1 (the lightest neutralino) Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

48 .... More candidates σ int (pb) Some Dark Matter Candidate Particles [Baer & Tata, ] fuzzy CDM neutrinos axion WIMPs : neutralino KK photon branon LTP Q-ball axino SuperWIMPs : gravitino KK graviton wimpzilla mass (GeV) Black Hole Remnant Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

49 .... and discussions Dark matter connects our knowledge of the Universe from the largest to the smallest scales. Cosmology Astrophysics Dark matter Particle physics Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

50 .... and discussions Current and near future dark matter searching experiments are promising to solve the mystery of dark matter. Inirect detection DM SM Unknown physics DM SM Collider detection Direct detection Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

51 .... Thanks for your attentions! Zhao-Huan Yu (IHEP) Dark matter: evidence and candidates Mar / 23

DARK MATTER. Martti Raidal NICPB & University of Helsinki Tvärminne summer school 1

DARK MATTER. Martti Raidal NICPB & University of Helsinki Tvärminne summer school 1 DARK MATTER Martti Raidal NICPB & University of Helsinki 28.05.2010 Tvärminne summer school 1 Energy budget of the Universe 73,4% - Dark Energy WMAP fits to the ΛCDM model Distant supernova 23% - Dark