Georg G. Raffelt, Max-Planck-Institut für Physik, München. Dark Matter. Axion Dark Matter. Physics Colloquium, University of Sydney, 3 March 2014

Transcription

1 Dark Matter Georg G. Raffelt, Max-Planck-Institut für Physik, München Axion Dark Matter Physics Colloquium, University of Sydney, 3 March 2014

2 Axions as Cold Dark Matter of the Universe Dark Energy ~70% (Cosmological Constant) Ordinary Matter ~5% (of this only about 10% luminous) Dark Matter ~25% Neutrinos 0.1-2%

3 Periodic System of Elementary Particles Quarks Charge -1/3 Charge +2/3 Down d Up u Leptons Charge -1 Charge 0 Electron e e-neutrino n e Neutron Proton

4 Periodic System of Elementary Particles 1 st Family 2 nd Family 3 rd Family Charge -1/3 Down d Strange s Bottom b Gravitation (Gravitons?) Quarks Leptons Charge +2/3 Up u Charm c Neutron Top Strong Interaction (8 Gluons) Electromagnetic Interaction (Photon) Proton Weak Interaction (W and Z Bosons) t Charge -1 Charge 0 Electron Muon Tau e e-neutrino n e m m-neutrino n e n m t t-neutrino n t

5 Periodic System of Elementary Particles 1 st Family 2 nd Family 3 rd Family Higgs Charge -1/3 Down d Strange s Bottom b Gravitation (Gravitons?) Quarks Leptons Charge +2/3 Up u Charm c Neutron Top Strong Interaction (8 Gluons) Electromagnetic Interaction (Photon) Proton Weak Interaction (W and Z Bosons) t Charge -1 Charge 0 Electron Muon Tau e e-neutrino n e m m-neutrino n e n m t t-neutrino n t

6 Supersymmetric Extension of Particle Physics In supersymmetric extensions of the particle-physics standard model, every boson has a fermionic partner and vice versa Spin 1/2 Leptons (e, n e, ) Quarks (u, d, ) 1 Gluons W Z 0 Photon (g) 0 2 Standard particle Higgs Graviton Superpartner Sleptons (e, ν e, ) Squarks (u, d, ) Gluinos Wino Zino Photino (γ) Higgsino Gravitino Spin If R-Parity is conserved, the lightest SUSY-particle (LSP) is stable Most plausible candidate for dark matter is the neutralino, similar to a massive Majorana neutrino Neutralino = C 1 Photino + C 2 Zino + C 3 Higgsino 0 1/2 1/2 3/2

7 Laboratory Searches for WIMP Dark Matter Galactic dark matter particle (e.g. neutralino) Energy deposition Recoil energy (few kev) is measured by Ionisation Scintillation Cryogenic

8 WIMP Searches (Underground Physics) COUPP PICASSO Heat Phonons CDMS EDELWEISS CRESST ROSEBUD Charge Light DRIFT GERDA XENON LUX, ZEPLIN WARP, ArDM DEAP/CLEAN DAMA/LIBRA KIMS, XMASS

9 WIMP Cross Section Limits 2014 Klaus Eitel, 2014

10 High- and Low-Energy Frontiers in Particle Physics Cosmological constant QCD scale Electroweak scale GUT scale Planck mass ev CERN Accelerator Frontier WIMP dark matter (related to EW scale, perhaps SUSY) Axion dark matter (related to Peccei-Quinn symmetry) m π f π /f a m π, f π f a

11 Axion Physics in a Nut Shell Particle-Physics Motivation CP conservation in QCD by Peccei-Quinn mechanism Axions a ~ p 0 m p f p m a f a For f a f p axions are invisible and very light a g g Solar and Stellar Axions Axions thermally produced in stars, e.g. by Primakoff production g a Limits from avoiding excessive energy drain Solar axion searches (CAST, Sumico) Cosmology Search for Axion Dark Matter In spite of small mass, axions are born non-relativistically (non-thermal relics) N Microwave resonator (1 GHz = 4 mev) a g Cold dark matter candidate m a ~ 10 mev (or much smaller or larger) S Primakoff conversion B ext ADMX-LF (UW Seattle) ADMX-HF (Yale)

12 CP Violation in Particle Physics Discrete symmetries in particle physics C Charge conjugation, transforms particles to antiparticles violated by weak interactions P Parity, changes left-handedness to right-handedness violated by weak interactions T Time reversal, changes direction of motion (forward to backward) CPT exactly conserved in quantum field theory CP conserved by all gauge interactions violated by three-flavor quark mixing matrix M. Kobayashi T. Maskawa Physics Nobel Prize 2008 All measured CP-violating effects derive from a single phase in the quark mass matrix (Kobayashi-Maskawa phase), i.e. from complex Yukawa couplings Cosmic matter-antimatter asymmetry requires new ingredients

13 The CP Problem of Strong Interactions Real quark mass Phase from Yukawa coupling Angle variable CP-odd quantity E B L QCD = ψ q id m q e iθ q ψ q 1 4 q ψ q e iγ 5θ q /2 ψ q L QCD = ψ q id m q ψ q 1 GG 4 q G μνa G a μν Θ α s 8π G μνag a μν Remove phase of mass term by chiral transformation of quark fields Θ can be traded between quark phases and GG term No physical impact if at least one m q = 0 Θ arg det M q π Θ +π Induces a large neutron electric dipole moment (a T-violating quantity) α s 8π GG Experimental limits: Θ < Why so small?

14 Neutron Electric Dipole Moment Violates time reversal (T) and space reflection (P) symmetries Natural scale e 2m N = e cm Experimental limit d = e cm Limit on coefficient Θ m q m N 10 11

15 Strong CP Problem QCD vacuum energy V(Θ) 4 Λ QCD Equivalent Equivalent 2π π +π +2π Θ CP conserving vacuum has Θ = 0 (Vafa and Witten 1984) QCD could have any π Θ +π, is constant of nature Energy can not be minimized: Θ not dynamical

16 Strong CP Problem QCD vacuum energy V(Θ) 4 Λ QCD Equivalent Equivalent 2π π +π +2π Θ CP conserving vacuum has Θ = 0 (Vafa and Witten 1984) QCD could have any π Θ +π, is constant of nature Energy can not be minimized: Θ not dynamical Peccei-Quinn solution: Make Θ dynamical, let system relax to lowest energy

17 The Pool Table Analogy (Pierre Sikivie 1996) Gravity Pool table Symmetric relative to gravity

18 The Pool Table Analogy (Pierre Sikivie 1996) Gravity Pool table Symmetric relative to gravity Floor inclined Symmetry broken

19 The Pool Table Analogy (Pierre Sikivie 1996) Gravity Pool table Axis Symmetric relative to gravity Floor inclined Symmetry broken f a Symmetry dynamically restored (Peccei & Quinn 1977)

20 The Pool Table Analogy (Pierre Sikivie 1996) Gravity Pool table Axis Symmetric relative to gravity Floor inclined Symmetry broken f a New degree of freedom Axion (Weinberg 1978, Wilczek 1978) Θ Symmetry dynamically restored (Peccei & Quinn 1977)

21 35 Years of Axions

22 The Cleansing Axion Frank Wilczek I named them after a laundry detergent, since they clean up a problem with an axial current. (Nobel lecture 2004)

23 Axion Bounds and Searches [GeV] f a m a kev ev mev mev nev Experiments Tele scope CAST Direct searches ADMX (Seattle & Yale) Too much hot dark matter Too much CDM cold dark matter (re-alignment (misalignment) with Q i = 1) Globular clusters (a-g-coupling) SN 1987A Too many events Too much energy loss Globular clusters (He ignition), WD cooling (a-e coupling) Classic region Anthropic region

24 Axions as Cold Dark Matter of the Universe Dark Energy ~70% (Cosmological Constant) Ordinary Matter ~5% (of this only about 10% luminous) Dark Matter ~25% Neutrinos 0.1-2%

25 Creation of Cosmological Axions T ~ f a (very early universe) U PQ (1) spontaneously broken Higgs field settles in Mexican hat Axion field sits fixed at a i = Θ i fa T ~ 1 GeV (H ~ 10 9 ev) Axion mass turns on quickly by thermal instanton gas Field starts oscillating when m a 3H Classical field oscillations (axions at rest) V(a) a V(a) a Θ = 0 Axions are born as nonrelativistic, classical field oscillations Very small mass, yet cold dark matter

26 Axion Cosmology in PLB 120 (1983)

27 Killing Two Birds With One Stone Peccei-Quinn mechanism Solves strong CP problem Provides dark matter in the form of axions

28 Cosmic Axion Density Modern values for QCD parameters and temperature-dependent axion mass imply (Bae, Huh & Kim, arxiv: ) Ω a h 2 = Θ i 2 f a GeV = Θ i 2 10 μev m a If axions provide the cold dark matter: Ω a h 2 = 0.11 Θ i = GeV f a = 1.0 m a 10 μev Θ i 1 implies f a GeV and m a ~ 10 mev ( classic window ) f a GeV (GUT scale) or larger (string inspired) requires Θ i ( anthropic window )

29 High- and Low-Energy Frontiers in Particle Physics Cosmological constant QCD scale Electroweak scale GUT scale Planck mass ev CERN Accelerator Frontier WIMP dark matter (related to EW scale, perhaps SUSY) Axion dark matter (related to Peccei-Quinn symmetry) m π f π /f a m π, f π f a

30 Axion Production by Domain Wall and String Decay Recent numerical studies of collapse of string-domain wall system Ω a h 2 = 8.4 ± 3.0 f a GeV 1.19 g, Λ 400 MeV Implies a CDM axion mass of m a 0.3 mev Hiramatsu, Kawasaki, Saikawa & Sekiguchi, arxiv: (2012) Remains to be confirmed, interpretation of numerical studies not entirely straightforward

31 BEC Formation Axions ~ WIMP dark matter on scales axion Compton wavelength? Larger-range correlation established by BEC dynamics? (Observable?) Axions born as classical field oscillations Issue of classical field dynamics (not a quantum effect) BEC formation caused by gravitational interactions possible??? See also Erken, Sikivie, Tam & Yang, arxiv: Saikawa & Yamaguchi, arxiv: Noumi, Saikawa, Sato & Yamaguchi, arxiv: Davidson & Elmer, arxiv: Berges & Jaeckel, arxiv:

32 Searching for Solar Axions Searching for Axion-Like Particles

33 Experimental Tests of Invisible Axions Primakoff effect: Axion-photon transition in external static E or B field (Originally discussed for π 0 by Henri Primakoff 1951) Pierre Sikivie: Macroscopic B-field can provide a large coherent transition rate over a big volume (low-mass axions) Axion helioscope: Look at the Sun through a dipole magnet Axion haloscope: Look for dark-matter axions with A microwave resonant cavity

34 Search for Solar Axions g Primakoff production a Axion flux a Axion Helioscope (Sikivie 1983) Magnet N S g Sun Axion-Photon-Oscillation Tokyo Axion Helioscope ( Sumico ) (Results since 1998, up again 2008) CERN Axion Solar Telescope (CAST) (Data since 2003) Alternative technique: Bragg conversion in crystal Experimental limits on solar axion flux from dark-matter experiments (SOLAX, COSME, DAMA, CDMS...)

35 Tokyo Axion Helioscope ( Sumico ) ~ 3 m Moriyama, Minowa, Namba, Inoue, Takasu & Yamamoto PLB 434 (1998) 147 Inoue, Akimoto, Ohta, Mizumoto, Yamamoto & Minowa PLB 668 (2008) 93

36 CAST at CERN

37 Photon Regeneration Experiments Ehret et al. (ALPS Collaboration), arxiv: Recent shining-light-through-a-wall or vacuum birefringence experiments: ALPS BMV BFRT GammeV LIPPS OSQAR PVLAS (DESY, using HERA dipole magnet) (Laboratoire National des Champs Magnétiques Intens, Toulouse) (Brookhaven, 1993) (Fermilab) (Jefferson Lab) (CERN, using LHC dipole magnets) (INFN Trieste)

38 Shining TeV Gamma Rays through the Universe Figure from a talk by Manuel Meyer (Univ. Hamburg)

39 Shining TeV Gamma Rays through the Universe Figure from a talk by Manuel Meyer (Univ. Hamburg)

40 Parameter Space for Axion-Like Particles π η a WW Invisible axion (DM)

41 Parameter Space for Axion-Like Particles HB Stars π η a WW Invisible axion (DM)

42 Parameter Space for Axion-Like Particles CAST Solar Axions HB Stars π η a WW Invisible axion (DM)

43 Parameter Space for Axion-Like Particles Laser Experiments CAST Solar Axions HB Stars π η a WW Invisible axion (DM)

44 Parameter Space for Axion-Like Particles Laser Experiments CAST Solar Axions HB Stars π η a WW TeV g rays Invisible axion (DM)

45 Parameter Space for Axion-Like Particles How to make progress? Laser Experiments CAST Solar Axions HB Stars π η a WW TeV g rays Invisible axion (DM)

46 Next Generation Axion Helioscope (IAXO) at CERN Need new magnet w/ Much bigger aperture: ~1 m 2 per bore Lighter (no iron yoke) Bores at T room Irastorza et al.: Towards a new generation axion helioscope, arxiv: Armengaud et al.: Conceptual Design of the International Axion Observatory (IAXO), arxiv:

47 Searching for Axion Dark Matter Searching for Axion Dark Matter

48 Search for Galactic Axions (Cold Dark Matter) Dark matter axions Velocities in galaxy Energies therefore m a = mev v a 10-3 c E a ( ) m a Microwave Energies (1 GHz 4 mev) Axion Haloscope (Sikivie 1983) B ext 8 Tesla Microwave Resonator Q 10 5 Power Frequency m a Axion Signal Thermal noise of cavity & detector Primakoff Conversion a g Cavity overcomes momentum B ext mismatch Power of galactic axion signal W m a 2π GHz 2 Q V B 0.22 m T 10 5 ρ a g/cm 3

49 Axion Dark Matter Experiment (ADMX), Seattle Georg Raffelt, MPI Physics, Munich Adapted from Gianpaolo Carosi Physics Colloquium, Univ. Sydney, 3 March 2014

50 SQUID Microwave Amplifiers in ADMX Georg Raffelt, MPI Physics, Munich Adapted from Gianpaolo Carosi Physics Colloquium, Univ. Sydney, 3 March 2014

51 Axion Dark Matter Searches Limits assuming axions are the galactic dark matter with standard halo Rochester-Brookhaven- Fermilab, PRD 40 (1989) University of Florida PRD 42 (1990) US Axion Search ApJL 571 (2002) L27 4. CARRACK I (Kyoto) hep-ph/

52 Axion Dark Matter Searches Limits assuming axions are the galactic dark matter with standard halo Rochester-Brookhaven- Fermilab, PRD 40 (1989) University of Florida PRD 42 (1990) US Axion Search ApJL 571 (2002) L27 4. CARRACK I (Kyoto) hep-ph/ ADMX-LF (Seattle) search range (2015+)

53 ADMX-HF at Yale (Steve Lamoreaux Group) Design of cavity & magnet Dilution refrigerator above & below deck ADMX-HF will also be a test-bed for innovative concepts, e.g. thin-film superconducting cavities Georg Raffelt, MPI Physics, Munich Adapted from Karl van Bibber Physics Colloquium, Univ. Sydney, 3 March 2014

54 WISPDMX at DESY and MPIfR Microwave cavities: HERA 50, 208, 500 MHz 208 MHz cavity: resonant modes at 199, 295, 433, 524, 579, 707, 765, 832 MHz Magnets: DESY H1 1.1 T (solenoid), HERA 5 T (dipole), Receiver technology: MPIfR, T n ~ 100 K Phase 1,2 searches using available facilities Phase 3 advanced searches with specially designed facilities 208 MHz microwave cavities H1 detector

55 Broadband Approaches Focusing the DM signal w/ spherical reflector P out A reflector ω 2 Feasible above 10 GHz TOKAMAKs: - Optimize B 2 V factor in a radiometer mode - Good at low frequencies - Design study under way (Lobanov et al. 2013) Horns et al TOKAMAK Facility B [T] V [m 3 ] B 2 V [T 2 m 3 ] ToreSupra JET ITER MPP ASDEX TEXTOR Microwave cavity experiment B [T] V [m 3 ] B 2 V [T 2 m 3 ] ADMX WISPDMX

56 Center for Axion and Precision Physics (CAPP) Yannis Semertzidis 15 Oct 2013 New Institute for Basic Science (IBS), Korea The plan is to launch a competitive Axion Dark Matter Experiment in Korea, participate in stateof-the-art axion experiments around the world, play a leading role in the proposed proton electric-dipole-moment (EDM) experiment and take a significant role in storage-ring precision physics involving EDM and muon g 2 experiments.

57 What if the axion is found?

58 1D Infall and the Folding of Phase Space

59 Fine Structure in the Axion Spectrum Axion distribution on a 3-dim sheet in 6-dim phase space Is folded up by galaxy formation Velocity distribution shows narrow peaks that can be resolved More detectable information than local dark matter density P.Sikivie & collaborators

60 Axion Bounds and Searches [GeV] f a m a kev ev mev mev nev Experiments Tele scope CAST Direct searches ADMX (Seattle & Yale) Too much hot dark matter Too much CDM cold dark matter (re-alignment (misalignment) with Q i = 1) Globular clusters (a-g-coupling) SN 1987A Too many events Too much energy loss Globular clusters (He ignition), WD cooling (a-e coupling) Classic region Anthropic region

61 Oscillating Neutron EDM by Axion Dark Matter 4 Λ QCD π Assume axions are galactic dark matter: ρ a ~ 300 MeV/cm 3 ρ a = m a 2 Φ a 2 = m a 2 Θ = a/f a +π Oscillating axion field (DM) Oscillating Q term Oscillating neutron EDM Θf 2 a Θ 2 m π f 2 π Θ 2 4 Λ QCD Independently of f a expect Θ t cos m a t Expect time-varying neutron EDM, MHz frequency for f a ~ 1016 GeV d n e m q Θ e cm cos m 2m n m a t N 8 orders of magnitude below limit on static EDM, but oscillates!

62 Searching for Axions in the Anthropic Window CASPEr experiment Precise magnetometry to measure tiny deviations from Larmor frequency Graham & Rajendran, arxiv: Budker, Graham, Ledbetter, Rajendran & Sushkov, arxiv:

63 Cosmic Axion Spin Precession Experiment (CASPEr) Time-varying nucleon EDM caused by axion DM in Lead Titanate magnetometer Phase I Phase II Budker, Graham, Ledbetter, Rajendran & Sushkov, arxiv:

64 Helmholtz Institute Mainz (HIM) Dmitry Budker Moving from Berkeley to HIM Plans to pursue CASPEr New institute on Structure, symmetry and stability of matter and antimatter Building under construction

65 Dow Jones Index of Axion Physics inspire: Citation of Peccei-Quinn papers or title axion (and similar)

66 Pie Chart of Dark Universe Dark Energy ~70% (Cosmological Constant) Ordinary Matter ~5% (of this only about 10% luminous) Dark Matter ~25% Neutrinos 0.1-2%