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

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)?

2-12-05 Durham

2-12-05 Durham

SUSY dark matter

• The lightest Neutralino

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 M GUT theories) or at the EW scale ( effMSSM ) (e.g., coming from SUGRA 2) Effect of experimental constraints?

masses of superpartners Low energy observables ( (g-2) m , b  s g , B S  m + m , … ) 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, H 1 , H 2 The detection properties of the neutralino depend on its composition 2-12-05 Durham

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 2-12-05 Durham

Neutralinos

2-12-05 Durham m Hd 2 m Hu 2 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 M GUT Non-universal soft terms (e.g., in the Higgs sector) m Hu 2 m Hd 2  

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 2-12-05 Durham m Hd 2 m Hu 2 M I M GUT Non-universal soft terms (e.g., in the Higgs sector) Or intermediate scales m Hu 2 m Hd 2  

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 M 1 << M 2 , m M 1  m < M 2 2-12-05 Durham

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 2-12-05 Durham

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 2-12-05 Durham

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.

2-12-05 Durham

2-12-05 Durham

SUSY dark matter

• The lightest Neutralino • The Gravitino

Gravitinos

• The gravitino can be the LSP in Supergravity The gravitino mass depends on the SUSY-breaking mechanism Anomaly-Mediated (

AMSB

) Gravity-mediated (

GMSB

) Gaugino-Mediated Gauge-Mediated m 3/2 =

O

(10 4 – 10 5 GeV) >> m, M m 3/2 =

O

(10 2 – 10 3 GeV) ~ m, M m 3/2 =

O

(10 -2 – 10 2 GeV) m, M m 3/2 =

O

(10 -10 – 10 -8 GeV) << m, M Gravitino not LSP Gravitino LSP in some regions of the parameter space Gravitino LSP 2-12-05 Durham

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)   g   Z ,   W • 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 2-12-05 Durham