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					Georg G. Raffelt, Max-Planck-Institut für Physik, München
                         Axions




                              Motivation, Cosmological Role
                               and Experimental Searches
 Physics Theory Colloquium, 16 Feb 2010, TIFR, Mumbai
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                Axion Physics in a Nut Shell
              Particle-Physics Motivation                                      Solar and Stellar Axions
   CP conservation in QCD by                                          Axions thermally produced in stars,
   Peccei-Quinn mechanism                                             e.g. by Primakoff production
                                                                  γ             γ           a
   → Axions a ~ π0
                                                  a
            mπfπ ≈ mafa
                                                                  γ   • Limits from avoiding excessive
   For fa ≫ fπ axions are “invisible”                                   energy drain
   and very light                                                     • Solar axion searches (CAST, Sumico)

                                  Cosmology                               Search for Axion Dark Matter

   In spite of small mass, axions are born                                                Microwave resonator
   non-relativistically                                                   N               (1 GHz = 4 μeV)
   (non-thermal relics)                                                                       a            γ
                                                                                          Primakoff
                                                                                          conversion                          Bext
   Cold dark matter
   candidate                                                               S              ADMX (Livermore)
   ma ~ 10 μeV or even smaller                                                            New CARRACK (Kyoto)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                    Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                           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 theories
 CP – conserved by all gauge interactions
      violated by three-flavor quark mixing matrix




                                                                  All known CP-violating effects derive from
                                                                  a single phase in the quark mass matrix
                                                                  (Kobayashi-Maskawa phase),
   M. Kobayashi                           T. Maskawa              i.e. from complex Yukawa couplings
       Physics Nobel Prize 2008
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                      Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                         Cabbibo-Kobayashi-Maskawa (CKM) Matrix
                                                                  g
  Quark interaction with W boson                                                        +
                                                                     ψuL γ μ VCKM ψ dL Wμ + h.c.
  (charged-current electroweak interaction)                        2
                                                                  ψu = (u, c, t )               ψ d = (d, s, b)

  Unitary Cabbibo-Kobayashi-Maskawa matrix        ⎛ Vud                                   Vus          Vub ⎞
  relates mass eigenstates                        ⎜                                                        ⎟
                                           VCKM = ⎜ Vcd                                   Vcs          Vcb ⎟
  to weak interaction eigenstates                 ⎜V
                                                  ⎝ td                                    Vts          Vtb ⎟
                                                                                                           ⎠
  VCKM depends on three mixing angles and one phase δ,
  explaining all observed CP-violation

  Precision tests use “unitarity triangles” consisting of products of measured
  components of VCKM, for example:




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany          Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                           Measurements of CKM Unitarity Triangle




                    CKMfitter Group                                UTfit Collaboration
                http://ckmfitter.in2p3.fr                         http://www.utfit.org

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany      Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                       Kobayashi and Maskawa




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany          Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                              The CP Problem of Strong Interactions
                                                    Real  Phase from           Angular               CP-odd
                                                    quark Yukawa               variable              quantity ~E⋅B
                                                    mass coupling

                       ⎛ iD − m e iθq ⎞ψ − 1 G Gμν − Θ α s G Gμν
           LQCD = ∑ ψq ⎜ /            ⎟ q 4 μνa a
                                                               ~
                               q                            μνa a
                  q    ⎝              ⎠                8π

  Remove phase of mass term by chiral phase transformation of quark fields
                                 − i γ 5θ q 2
            ψq → e                                     ψq
                                     1 GG − (Θ − arg det M ) α s GG
                                                                  ~
                        /
           LQCD = ∑ ψq(iD − mq)ψ q − 4
                                            1442443 8π      q
                  q
                                               − π< Θ < + π
                                                 ~
  • Θ can be traded between quark phases and GG term
  • Induces a large neutron electric dipole moment (a T-violating quantity)


                    Experimental limits:                          Θ < 10 −10      Why so small?

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                 Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                         Neutron Electric Dipole Moment

                                                                  Violates time reversal (T) and
                                                                  space reflection (P) symmetries




                                                                  Natural scale
                                                                   e/2mN = 1.06 × 10−14 e cm
                                                                  Experimental limit
                                                                   |d| < 0.63 × 10−25 e cm

                                                                  Limit on coefficient
                                                                      mq
                                                                    Θ m < 10 −11
                                                                         ≲
                                                                       N

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany             Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                                  Dynamical Solution
                              Peccei & Quinn 1977, Wilczek 1978, Weinberg 1978

   • Re-interpret Θ as a dynamical variable (scalar field)
                                                 αs       ~      α s a(x)     ~
                                         LCP = −    Θ Tr(GG) → −          Tr(GG)
                                                 8π              8π fa
       a(x) pseudoscalar axion field, fa axion decay constant (Peccei-Quinn scale)
   • Axions generically couple to two gluons and mix with π0, η, η’ mesons,
     inducing a mass (potential) for a(x)
                           mumd              ⎛ Axion mass ⎞ ⎛ Pion mass ⎞ fπ
                  ma fa =         mπ fπ      ⎜             ⎟~⎜             ⎟×
                          mu + md            ⎝ & couplings ⎠ ⎝ & couplings ⎠ fa
   • Potential (mass term) induced by LCP drives a(x) to CP-conserving minimum
                                 V(a)     CP-symmetry
                                          dynamically
                                          restored

                                                                         a
                                                                   Θ=0
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                    Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                       Peccei-Quinn Mechanism Proposed in 1977




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                   The Pool Table Analogy (Pierre Sikivie 1996)

      Gravity                                            Pool table
                                                                                           Symmetric
                                                                                           relative
                                                                                           to gravity




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany       Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                   The Pool Table Analogy (Pierre Sikivie 1996)

      Gravity                                            Pool table
                                                                                               Symmetric
                                                                                               relative
                                                                                               to gravity



                                                                         Floor                 Symmetry
                                                                      inclined                 broken




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany           Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                   The Pool Table Analogy (Pierre Sikivie 1996)

      Gravity                                            Pool table
                                                                                                  Symmetric
                                                                                                  relative
                                                                                                  to gravity
                                                                  Axis

                                                                            Floor                 Symmetry
                                                                         inclined                 broken



                                                                                                  Symmetry
                                                                                                  dynamically
                                                                                                  restored
                                                                                   (Peccei & Quinn 1977)

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany              Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                   The Pool Table Analogy (Pierre Sikivie 1996)

      Gravity                                            Pool table
                                                                                                       Symmetric
                                                                                                       relative
                                                                                                       to gravity
                                                                  Axis

                                                                                 Floor                 Symmetry
                                                                              inclined                 broken

                                                                         fa
                                                                  _
 New degree                                                       Θ                                    Symmetry
 of freedom                                                                                            dynamically
 → Axion                                                                                               restored
 (Weinberg 1978, Wilczek 1978)                                                          (Peccei & Quinn 1977)

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                                  33 Years of Axions




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                        Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                             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
                                                                                          written version)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                  Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                                       Axion Bounds

                                                                                                                              [GeV] fa
                103                                  106                      109       1012                                1015

                         keV                                      eV            meV               μeV                                  neV
 ma

                                                   Tele                                Direct ADMX
 Experiments                                                           CAST
                                                   scope                              searches CARRACK

   Too much hot dark matter                                                                  Too much
                                                                                             cold dark matter (classic)

                   Globular clusters                                                  Classic                                     Anthropic
                    (a-γ-coupling)                                                    region                                       region
                       Too many                                Too much
                        events                                energy loss
                         SN 1987A (a-N-coupling)


Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                          Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                           Supernova 1987A Energy-Loss Argument
                                                                  Neutrino   SN 1987A neutrino signal
                                                                   sphere


                                                       Volume emission
                                                       of novel particles
                      Neutrino
                      diffusion




   Emission of very weakly interacting
   particles would “steal” energy from the
   neutrino burst and shorten it.
   (Early neutrino burst powered by accretion,
    not sensitive to volume energy loss.)

   Late-time signal most sensitive observable

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                  Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                    Axions as Nambu-Goldstone Bosons

           αs      ~    αs ⎛    a(x) ⎞    ~
    L CP =    Θ Ga Ga →    ⎜Θ −      ⎟ Ga G a
           8π           8π ⎜
                           ⎝     fa ⎟⎠
                            14243
                                                         Periodic variable (angle)
                                                            fa + ρ(x) ia( x) fa
                                                         Φ=          e
                                                                 2

   • New U(1) symmetry, spontaneously broken at a large scale fa
   • Axion is “phase” of new Higgs field: angular variable a(x)/fa
                                                                        ~
   • By construction couples to GG term with strength αs/8π,
     e.g. triangle loop with new heavy quark (KSVZ model)
   • Mixes with π0-η-η’ mesons
   • Axion mass                       mumd                                              mπ
                                ma =
     (vanishes if mu or md = 0)      mu + md                                            fπ fa
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                      Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                         Creation of Cosmological Axions
 T ~ fa (very early universe)                                                                                V(a)
 • UPQ(1) spontaneously broken
 • Higgs field settles in
  “Mexican hat”
                                                                                                                          a
 • Axion field sits fixed at
   a1 = Θ1 fa

 T ~ 1 GeV (H ~ 10−9 eV)
                                                                                                             V(a)
 • Axion mass turns on quickly
   by thermal instanton gas
 • Field starts oscillating when
   ma ≳ 3H                                                                                                                a
                                                                                                    _
 • Classical field oscillations                                                                     Θ=0
   (axions at rest)
 • Axion number density in comoving volume conserved
                    2 3        3 2 2
   naR 3 = ma (T1) a1 R1 ~ 3H1R1 Θ1 fa                  2 2
                                                       ma fa          2
                                                                  m2 fπ
                                          2     2    2
 • Axion mass density today: ρa = mana ∝ Θ1 ma fa ∝ Θ1       ∝ Θ1 π
                                                                2
                                                        ma         ma
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                   Axion Cosmology in PLB 120 (1983)

       Page 127




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                   Axion Cosmology in PLB 120 (1983)

      Page 133




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                   Axion Cosmology in PLB 120 (1983)

      Page 137




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                        Killing Two Birds with One Stone




                                                                  Peccei-Quinn mechanism
                                                                  • Solves strong CP problem
                                                                  • May provide dark matter
                                                                    in the form of axions



Georg Raffelt, Max-Planck-Institut für Physik, München, Germany      Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                           Cosmic Axion Density
  Modern values for QCD parameters and temperature-dependent axion mass
  imply (Bae, Huh & Kim, arXiv:0806.0497)

                                                                        1.184                                                1.184
                                                             ⎛    fa    ⎞                 2 ⎛ 10 μeV ⎞
            Ω ah2 = 0.195 Θ 2                                ⎜          ⎟       = 0.105 Θ i ⎜
                                                                                            ⎜ m ⎟    ⎟
                            i                                ⎜ 1012 GeV ⎟                   ⎝     a ⎠
                                                             ⎝          ⎠

  If axions provide the cold dark matter: Ωah2 = 0.11


                       ⎛ 1012 GeV ⎞ 0.592       ⎛ ma ⎞
                                                           0.592
                       ⎜          ⎟       = 1.0 ⎜
            Θ i = 0.75
                       ⎜    fa    ⎟             ⎜ 10 μeV ⎟
                                                         ⎟
                       ⎝          ⎠             ⎝        ⎠

  • Θi ~ 1 implies fa ~ 1012 GeV and ma ~ 10 μeV
    (“classic window”)

  • fa ~ 1016 GeV (GUT scale) or larger (string inspired) requires Θi ≲ 0.003
   (“anthropic window”)

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                       Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                  Lee-Weinberg Curve for Neutrinos and Axions

    Axions                                       Non-Thermal
                                                                           Thermal Relics
                                         log(Ωa)    Relics

                                                                    CDM     HDM
                                                 ΩM


                                                                                                                                 log(ma)
                                                                  10 μeV     10 eV


  Neutrinos                              log(Ων)                                Thermal Relics
  & WIMPs                                                                    HDM                           CDM
                                                ΩM


                                                                                                                                 log(mν)
                                                                             10 eV                     10 GeV

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                      Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
            Axion Hot Dark Matter Limits from Precision Data
                                                                   Credible regions for neutrino plus axion hot
                                                                   dark matter (WMAP-5, LSS, BAO, SNIa)
                                                                   Hannestad, Mirizzi, Raffelt & Wong
                                                                   [arXiv:0803.1585]




                                68%             95%




Marginalizing over unknown neutrino hot dark matter component
 ma < 1.0 eV (95% CL)                                     WMAP-5, LSS, BAO, SNIa    Hannestad, Mirizzi, Raffelt
                                                                                    & Wong [arXiv:0803.1585]
 ma < 0.4 eV (95% CL)                                     WMAP-3, small-scale CMB, Melchiorri, Mena & Slosar
                                                          HST, BBN, LSS, Ly-α      [arXiv:0705.2695]

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                      Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                        Cold Axion Populations
 Case 1:                                                           Case 2:
 Inflation after PQ symmetry breaking                              Reheating restores PQ symmetry
 Homogeneous mode oscillates after                                 • Cosmic strings of broken UPQ(1)
              T ≲ ΛQCD                                               form by Kibble mechanism
 Dependence on initial misalignment                                • Radiate long-wavelength axions
 angle                                                             • Ωa independent of initial conditions
              Ωa ∝ Θ2 i                                            • N = 1 or else domain wall problem
 Dark matter density a cosmic random
 number (“environmental parameter”)

 • Isocurvature fluctuations from large                            Inhomogeneities of axion field large,
   quantum fluctuations of massless                                self-couplings lead to formation of
   axion field created during inflation                            mini-clusters
 • Strong CMB bounds on isocurvature                               Typical properties
   fluctuations                                                    • Mass ~ 10−12 Msun
 • Scale of inflation required to be                               • Radius ~ 1010 cm
   small                                                           • Mass fraction up to several 10%



Georg Raffelt, Max-Planck-Institut für Physik, München, Germany               Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                          Inflation, Axions and Anthropic Selection
  If PQ symmetry is not restored after inflation
  • Axion density determined by initial random number −π < Θi < +π
  • Different in different patches of the universe
  • Our visible universe, after inflation, from a single patch
  • Axion/photon ratio a cosmic random number,
    chosen by spontaneous symmetry breaking process

  Allows for small Θi ≲ 0.003 and thus for fa at GUT or string scale
  • Is this “unlikely” or “unnatural” or “fine tuned”?
  • Should one design experiments for very small-mass axion dark matter?

  Difficult to form baryonic structures if baryon/dark matter density too low,
  posterior probability for small Θi not necessarily small
  • Linde, “Inflation and axion cosmology,” PLB 201:437, 1988
  • Tegmark, Aguirre, Rees & Wilczek,
    “Dimensionless constants, cosmology and other dark matters,”
    PRD 73:023505, 2006 [astro-ph/0511774]

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                  Posterior Dark Matter Probability Distribution




                                Tegmark, Aguirre, Rees & Wilczek,
                   “Dimensionless constants, cosmology and other dark matters,”
                            PRD 73:023505, 2006 [astro-ph/0511774]
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
       Creation of Adiabatic vs. Isocurvature Perturbations

 Inflaton field:                                                  Axion field:
 De Sitter expansion imprints                                     De Sitter
 scale invariant fluctuations                                     expansion
                                                                  imprints
                                                                  scale invariant
                                                                  fluctuations
                       Slow roll




                     Reheating
                                                                  Inflaton decay → radiation
 Inflaton decay → matter & radiation                              Axion field oscillates late → matter
 Both fluctuate the same:                                         Matter fluctuates relative to radiation:
 Adiabatic fluctuations                                           Entropy fluctuations
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany              Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
         Power Spectrum of CMB Temperature Fluctuations
  Sky map of CMBR temperature
  fluctuations
                        T(θ, ϕ ) − T
   Δ (θ, ϕ ) =
                              T




  Multipole expansion
                          ∞           l
   Δ (θ, ϕ ) = ∑                     ∑ a lmYlm (θ, ϕ )            Acoustic Peaks
                       l = 0 m= − l




  Angular power spectrum
                                            1     l
   Cl = a∗ma lm =
         l                                        ∑ a∗ma lm
                                                        l
                                          2l + 1 m= − l

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany           Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                             CMB Angular Power Spectrum

                                                                               Purely adiabatic


                                                                               Purely isocurvature




                             Hamann, Hannestad, Raffelt & Wong, arXiv:0904.0647

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                      Parameter Degeneracies

                                                                                              WMAP-5
                                                                                              WMAP-5 + LSS
                                                                                              Planck forecast
                                                                                              Cosmic Variance
                                                                                              Limited (CVL)




                             Hamann, Hannestad, Raffelt & Wong, arXiv:0904.0647

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany          Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                          Isocurvature Forecast

                                                         Hubble scale during inflation




                                                                                                                      Axion decay constant
                             Hamann, Hannestad, Raffelt & Wong, arXiv:0904.0647

Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                  Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                          Experimental Tests of the Invisible Axion




      Primakoff effect:                                           Pierre Sikivie:
      Axion-photon transition in external                         Macroscopic B-field can provide a
      static E or B field                                         large coherent transition rate over
      (Originally discussed for π0                                a big volume (low-mass axions)
       by Henri Primakoff 1951)                                   • Axion helioscope:
                                                                    Look at the Sun through a dipole
                                                                    magnet
                                                                  • Axion haloscope:
                                                                    Look for dark-matter axions with
                                                                    A microwave resonant cavity
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany               Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                        Search for Solar Axions
                                                                                   Axion Helioscope
                       Primakoff                                                   (Sikivie 1983)
                       production
                                                                                                       N
             γ                                      a             Axion flux   a                                                                       γ
                                                                                   Magnet      S
                                                                                   Axion-Photon-Oscillation
                               Sun

                                                                                    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 ...)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                             Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                   Tokyo Axion Helioscope (“Sumico”)




                                        ~3m


Moriyama, Minowa, Namba, Inoue, Takasu & Yamamoto
PLB 434 (1998) 147
Inoue, Akimoto, Ohta, Mizumoto, Yamamoto & Minowa
PLB 668 (2008) 93
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                                  CAST at CERN




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                  Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                              Sun Spot on CCD with X-Ray Telescope




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                            90 min tracking result


               ROI




                                                                  „suspicious pressure“




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany           Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                                  Helioscope Limits




                     CAST-I results: PRL 94:121301 (2005) and JCAP 0704 (2007) 010
                     CAST-II results (He-4 filling): JCAP 0902 (2009) 008
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                       Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                   Search for Galactic Axions (Cold Dark Matter)
       Dark matter axions ma = 1−1000 μeV
                                                                                           Microwave Energies
       Velocities in galaxy va ≈ 10−3 c
       Energies therefore Ea ≈ (1 ± 10−6) ma                                               (1 GHz ≈ 4 μeV)

      Axion Haloscope (Sikivie 1983)
                                                                      Power                           Axion Signal
                                            Bext ≈ 8 Tesla
                                                                                                      Thermal noise of
                                            Microwave                                                 cavity & detector
                                            Resonator
                                            Q ≈ 105
                                                                   Frequency                  ma

                                                                  Power of galactic axion signal
      Primakoff Conversion
                                                    γ                              V           2
        a
                                                                  4 × 10 − 21W       ⎛ B ⎞ Q
                                                                  4 10     W       3 ⎜ 8.5 T ⎟
                                            Cavity                           0.22 m ⎝        ⎠ 105
                                            overcomes
                                                                                  ⎛ ma ⎞⎛    ⎜         ρa         ⎞
                                                                                                                  ⎟
                                            momentum                             ×⎜
                                                                                  ⎜ 2π GHz ⎟⎜
                                                                                           ⎟
                           Bext             mismatch                              ⎝        ⎠⎝ 5 × 10 − 25 g / cm3 ⎟
                                                                                                                  ⎠
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                        Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                Axion Dark Matter Searches
Limits/sensitivities, assuming axions are the galactic dark matter
                                                                              1. Rochester-Brookhaven-
                                           3                                     Fermilab,
                                                          2           1          PRD 40 (1989) 3153

                                                                              2. University of Florida
                                                                                 PRD 42 (1990) 1297
                                                                  4           3. US Axion Search
                                                                                 ApJL 571 (2002) L27
                                                                          6
                                                                              4. CARRACK I (Kyoto)
                                        5                                        hep-ph/0101200

                                                                              5. ADMX (US) foreseen
                                                                                 RMP 75 (2003) 777

                                                                              6. New CARRACK (Kyoto)
                                                                                 K.Imai (Panic 2008)


Georg Raffelt, Max-Planck-Institut für Physik, München, Germany               Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                  ADMX (Gianpaolo Carosi, Fermilab, May 2007)




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                  ADMX (Gianpaolo Carosi, Fermilab, May 2007)




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                  ADMX (Gianpaolo Carosi, Fermilab, May 2007)




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                       Phase I operations: First-year science data




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                                  New CARRACK




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
                                                                                                            Kenichi Imai
                                                                                Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                         New CARRACK (Kyoto)




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany           Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                                       Axion Bounds

                                                                                                                              [GeV] fa
                103                                  106                      109       1012                                1015

                         keV                                      eV            meV               μeV                                  neV
 ma

                                                   Tele                                Direct ADMX
 Experiments                                                           CAST
                                                   scope                              searches CARRACK

   Too much hot dark matter                                                                  Too much
                                                                                             cold dark matter (classic)

                   Globular clusters                                                  Classic                                     Anthropic
                    (a-γ-coupling)                                                    region                                       region
                       Too many                                Too much
                        events                                energy loss
                         SN 1987A (a-N-coupling)


Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                          Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                                                                                     Karl van Bibber
                                                                  Axion correlations                                    at IDM 2008




Georg Raffelt, Max-Planck-Institut für Physik, München, Germany                        Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                      Fine Structure in Axion Spectrum
         • Axion distribution on a 3-D sheet in 6-D 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
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany   Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India
                                                                  Summary

  Peccei-Quinn dynamical CP symmetry restoration
  is better motivated than ever

  Provides well-motivated cold dark matter candidate
  in the form of axions

  Realistic full-scale search in “classic window” (ma ~ 1−100 μeV)
  is finally beginning (ADMX and New CARRACK)

  Isocurvature fluctuations could still show up
  (Planck, future CVL probe)

  Experimental approach in “anthropic window” (ma ≲ neV)
  is missing


Georg Raffelt, Max-Planck-Institut für Physik, München, Germany             Theoretical Physics Colloquium, 16 Feb 2010, TIFR, Mumbai, India

				
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