SUSY in the sky: supersymmetric dark matter

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SUSY in the sky supersymmetric dark matter

• David G. Cerdeño
• Institute for Particle Physics Phenomenology

Based on works with S.Baek, K.Y.Choi, C.Hugonie,
K.Jedamzik, Y.G.Kim, P.Ko, D.López-Fogliani,
C.Muñoz, R.R. de Austri, L.Roszkowski,
A.M.Teixeira
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Contents

• Present status
• Dark matter is a necessary ingredient in present
  models for the Universe
• but we have not identified it yet
• Can it be the Lightest Supersymmetric Particle
  (LSP)?
• Direct detection experiments will continue
  providing data in the near future.
• It may be detected in running or projected dark
  matter experiments?
• The lightest Neutralino?
• Or maybe not?
• The gravitino (or the axino)?

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SUSY dark matter

• The lightest Neutralino

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Direct detection of Neutralinos

• Could the lightest neutralino be found in direct
  detection experiments?

Direct detection through the elastic scattering
of a WIMP with nuclei inside a detector.
Many experiments around the world are currently
looking for this signal with increasing
sensitivities
How large can the neutralino detection cross
section be?
Could we explain a hypothetical WIMP detection
with neutralino dark matter?
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Neutralinos

• How large can the direct detection cross section
  for neutralinos be?

1) In which theory? (field content, interactions,
parameters) MSSM NMSSM
Parameters given at the GUT scale MGUT (e.g.,
coming from SUGRA theories) or at the EW scale
(effMSSM)
2) Effect of experimental constraints?
masses of superpartners Low energy
observables ( (g-2)m , b?sg, BS ? mm-, )
3) Reproduce the correct relic density?
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Neutralinos

• In the MSSM the mechanisms which allow for an
  increase in the detection cross section are well
  known

In the MSSM, the neutralino is a physical
superposition of the B, W, H1, H2
The detection properties of the neutralino depend
on its composition
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Neutralinos

• Large detection cross sections

Squark-exchange
Higgs-exchange
Leading contribution. It can increase when

• The Higgsino components of the neutralino
  increase

• The Higgs masses decrease

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Neutralinos
Higgs-exchange
Leading contribution. It can increase when

• The Higgsino components of the neutralino
  increase

• The Higgs masses decrease

In terms of the mass parameters in the RGE
mHd2
Non-universal soft terms (e.g., in the Higgs
sector)
MGUT
mHu2
mHu2 ?
mHd2 ?
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Neutralinos
Higgs-exchange
Leading contribution. It can increase when

• The Higgsino components of the neutralino
  increase

• The Higgs masses decrease

In terms of the mass parameters in the RGE
mHd2
Non-universal soft terms (e.g., in the Higgs
sector)
MGUT
MI
mHu2
mHu2 ?
Or intermediate scales
mHd2 ?
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Neutralinos
In a general Supergravity theory (Non-universal
soft supersymmetry-breaking terms in the scalar
and gaugino sector) the neutralino can be within
the reach of dark matter detectors for a wide
range of masses.
Very light Neutralinos Bino-like
Heavy Neutralinos Bino-Higgsino
M1 ltlt M2, m
M1 ? m lt M2
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Neutralinos

• Neutralinos in the NMSSM

In the Next-to-MSSM, the neutralino has a new
singlino (S) component.
The detection properties depend on the neutralino
composition
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Neutralinos

• Large detection cross sections in the NMSSM

Squark-exchange
Higgs-exchange
Leading contribution. It can increase when

• The Higgsino components of the neutralino
  increase

• The Higgs masses decrease

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Neutralinos

• Large detection cross sections in the NMSSM

Higgs-exchange
Leading contribution. It can increase when

• The Higgsino components of the neutralino
  increase

• The Higgs masses decrease

Higgses lighter than 70 GeV and mostly
singlet-like
The relic density for these neutralinos is still
to be calculated.
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SUSY dark matter

• The lightest Neutralino
• The Gravitino

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Gravitinos

• The gravitino can be the LSP in Supergravity

The gravitino mass depends on the SUSY-breaking
mechanism
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Gravitinos

• Gravitino production mechanisms

• Thermal production
• Through scattering processes and an annihilation
  with (s)particles during thermal expansion of the
  Early Universe.
• Non-thermal production
• Through late decays of the NLSP (normally staus
  or neutralinos)

• Constraints from Nucleosynthesis

Late decays of the NLSP can generate highly
energetic electromagnetic and hadronic fluxes
which may alter significantly the abundances of
light elements (thus spoiling the success of Big
Bang Nucleosynthesis).
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Gravitinos

• In mSUGRA

All the regions where the neutralino is the NLSP
are excluded by BBN constraints. Only part of
those areas with stau NLSP are left.
In order to obtain the correct relic density of
dark matter thermal production alone is not
sufficient. Important contributions from
non-thermal production are also necessary.
In the remaining regions the Fermi vacuum is
metastable. The global minimum breaks charge
and/or colour.
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Summary

• The identification of dark matter is still an
  open problem pointing towards physics beyond the
  SM. Supersymmetric dark matter is one of the most
  attractive possibilities with an interesting
  future

• The lightest neutralino (both in the MSSM and
  NMSSM) could explain a hypothetical detection of
  WIMP dark matter in the next generation
  experiments

• Gravitino dark matter would lead to an
  interesting phenomenology
• Charged observable LSP (stau)
• No detection in dark matter experiments
• The Fermi vacuum may be metastable

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