Casting Light on Dark Matter?

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Casting Light on Dark Matter?
John ELLIS, Kings College London CERN
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The Current Context

• Three major new experimental results
• The discovery of a Higgs boson _at_ LHC
• Constraints on models of dark matter
• But no evidence of dark matter particles
• Planck satellite data
• Consistent with ?CDM model
• Constraints on inflationary models
• First data from the AMS-02 experiment
• Rising positron fraction
• Astrophysics or dark matter annihilations?

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Unofficial Combination of Higgs Search Data from
March 6th

Is this the Higgs Boson?
No Higgs here!
No Higgs here!
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It Walks and Quacks like a Higgs

• Do couplings scale mass? With scale v?
• Red line SM, dashed line best fit

Global fit
JE Tevong You, arXiv1303.3879
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What else is there?

• Supersymmetry

• Successful prediction for Higgs mass
• Should be lt 130 GeV in simple models
• Successful predictions for Higgs couplings
• Should be within few of SM values
• Naturalness, GUTs, string,
• Could explain the dark matter

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Lightest Sparticle as Dark Matter

• Stable in many models because of conservation of
  R parity
• R (-1) 2S L 3B
• where S spin, L lepton , B baryon
• Particles have R 1, sparticles R -1
• Sparticles produced in pairs
• Heavier sparticles ? lighter sparticles
• Lightest supersymmetric particle (LSP) stable
• Present in Universe today as relic from Big Bang

Fayet
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Relic Density Calculation

• Freeze-out from thermal equilibrium
• Typical annihilation cross section 3 ? 10-26
  cm2
• Lower if coannihilation with related particles

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Supersymmetric Signature _at_ LHC
Look for missing transverse energy carried away
by dark matter particles
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Searches 5/fb _at_ 8 TeV
Supersymmetry Searches _at_ LHC
Classic missing-energy search
Multiple searches including b, leptons
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Global Fit to Supersymmetric Model
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Scan of CMSSM
Impacts of searches with full 2012 data
Update of Buchmueller et al arXiv1207.3715
p-value of simple models lt 10
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Global Fit to Supersymmetric Model
5
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Gluino mass
CMSSM
Update of Buchmueller, JE et al arXiv1207.3715
Favoured values of gluino mass significantly above
pre-LHC, gt 1.5 TeV
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Cosmological Inflation in Light of Planck

• A scalar in the sky? A Wess-Zumino model?

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Inflationary Models in Light of Planck

• Planck CMB observations consistent with inflation
• Tilted scalar perturbation spectrum
• ns 0.9585 0.070
• BUT strengthen upper limit on tensor
  perturbations r lt 0.10
• Challenge for simple
• inflationary models
• Starobinsky R2 to rescue?
• Supersymmetry to rescue?

Croon, JE Mavromatos arXiv1303.6253
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Higgs Inflation a Single Scalar?
Bezrukov Shaposhnikov, arXiv0710.3755

• Standard Model with non-minimal coupling to
  gravity
• Potential similar to Starobinsky, but not
  identical

BUT needs MH gt 127 GeV ? LHC?
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Supersymmetric Inflation in Light of Planck

• Supersymmetric Wess-Zumino (WZ) model consistent
  with Planck data

?4
?2
?
WZ
?2/3
Croon, JE, Mavromatos arXiv1303.6253
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No-Scale Supergravity Inflation

• The only good symmetry is a local symmetry
• Early Universe cosmology needs gravity
• Supersymmetry gravity Supergravity
• BUT potentials in generic supergravity models
  have potential holes with depths MP4
• Exception no-scale supergravity
• Appears in compactifications of string
• Flat directions, scalar potential global model
  controlled corrections

JE, Nanopoulos Olive, arXiv1305.1247, 1307.3537
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No-Scale Supergravity Inflation

• Good inflation for

Looks like R2 model
JE, Nanopoulos Olive, arXiv1305.1247, 1307.3537
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Strategies for Detecting Supersymmetric Dark
Matter

• Scattering on nucleus in laboratory
• ? A ? ? A
• Annihilation in core of Sun or Earth
• ? ? ? ? ? µ
• Annihilation in galactic centre, dwarf galaxies
• ? ? ? ? ?
• Annihilation in galactic halo
• ? ? ? positrons, antiprotons, ?

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Direct Searches for Dark Matter
New CDMS result
Best limit XENON100 with 225 days of
data Confusion at low WIMP masses?
Aprile et al.
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Global Fit to Supersymmetric Model
5
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Spin-independent Dark matter scattering
--- 1/fb ___ 5/fb
Excluded by XENON100
Excluded by LHC
Buchmueller, JE et al arXiv1207.3715
Favoured values of dark matter scattering cross
section significantly below XENON100
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Strategies for Detecting Supersymmetric Dark
Matter

• Scattering on nucleus in laboratory
• ? A ? ? A
• Annihilation in core of Sun or Earth
• ? ? ? ? ? µ
• Annihilation in galactic centre, dwarf galaxies
• ? ? ? ? ?
• Annihilation in galactic halo
• ? ? ? positrons, antiprotons, ?

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Neutralino Annihilation Rates
In some supersymmetric models may be much
smaller than order-of-magnitude estimate
JE, Olive Spanos, arXiv1106.0768
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Annihilation Branching Fractions
Vary in different regions of parameter space
Must be modelled correctly
JE, Olive Spanos, arXiv1106.0768
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Fermi ? line_at_ 130 GeV?
Weniger analysis claimed 4 s (3 s with
look-elsewhere effect)

• BUT Fermi Collaboration also sees bump in
  control sample of ?s from Earths limb
• Presumably a systematic effect

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AMS-02 on International Space Station (ISS)
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Positron Fraction Rising with E

• Dark Matter? Galactic cosmic rays? Local sources?

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Dark Matter Fit to AMS Positron Data

• Can find good fit ?2 18 with annihilation to
  tt- by modifying cosmic ray parameters

JE, Olive Spanos, in preparation
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Dark Matter Fit to AMS Positron Data

• BUT very large annihilation cross section
• 3 ? 10-23 cm2 gtgt required for relic density
• OR very large boost from halo density
  fluctuation(s)

JE, Olive Spanos, in preparation
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Galactic Cosmic Rays Alone?
Blum, Katz Waxman, arXiv1305.1324

• Rising positron fraction compatible with
  model-independent bound on secondary e

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Galactic Cosmic Rays Alone?

• Can fit positron data with modified cosmic-ray
  model
• BUT problems with e-, p

_
JE, Olive Spanos, in preparation
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Assume Local Source Constrain any extra Dark
Matter Contribution

• Dark Matter annihilation could give feature above
  otherwise smooth distribution

Bergstrom et al, arXiv1306.3983
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The LHC may cast light on dark matter
dark matter experiments may cast light
on fundamental questions in particle physics