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Dark Matter

Evidence

Possibilities

Detection ?

Mathieu Langer

(Many thanks to Gianfranco Bertone,

Institut d’Astrophysique de Paris)

Cosmological parameters : status

- Combination of ‘independent’ data
- Universe spatially flat :
‘Cosmological Constant’ : ~ 0.7

‘Matter’ : ~ 0.3

(rem : baryons ~ 0.04)

First Evidence : Velocity dispersion of galaxies in clusters

Coma cluster of Galaxies

Fritz Zwicky, 1933

Motions require more than

100 times more mass than visible!

Galactic rotation curves

Vera Rubin, 1970s

Rotation curves & Dark Matter

Image UV GALEX, A. Gil de Paz, 2006

disc vs. halo DM

- Mass/Luminosity ratio?
(Stellar pop. synth.)

- DM : density profile ?
(simulations,

poorly constrained at centre)

Broeils, 1992, A&A

Measure of a cluster density profile

- Image : X emission
- X emission is a function of density n, x ~ n2
- Question: What density profile can give the observed X ray emission ?

Line: Best Fit

Points: Observations

Abell 2319 – Image ROSAT

[millions of light years]

- Procedure:
- Identify the cluster centre
- Average azimuthally X emission
- Fit the emission profile
- Deduce the required density

First 3D map of DM distribution !

- High fidelity maps of DM distribution on large scales, resolved in angular resolution and depth thanks to the Cosmic Evolution Survey of the HST
- (2 degrees2)
- Shape of 71 galaxies per arcmin2
- shear field
- total projected mass
- Follow-up observations by VLT, Subaru, Cerro Tololo & Kitt Peak to get the redshifts

Massey et al., Nature, 7 Janvier 2007

“Direct proof” : the Bullet Cluster

- Optical image of merging clusters (here: 1E 0657-558)
- Reconstruct the shear and the convergence (grav. lensing)
- Projected density maps
- (green contours)

200 kpc

Clowe et al. ApJL 2006

“Direct proof” : the Bullet Cluster

- X-ray image of the same cluster, 1E 0657-558, by Chandra
- Green contours : convergence (prop. to the projected density)
- White contours : peaks of at 68.3%, 95.5% and 99.7% C.L.

200 kpc

Clowe et al. ApJL 2006

Presence of non-luminous gravitating mass !

1% Stars

7% Gas in virialised structures

Baryons

7% Warm/hot gas in IGM

Don’t know what Dark Matter is?

Ask a Particle Physicist!

85% DARK MATTER

Non-baryonic

Kaluza-Klein DM in RS

Axion

Axino

Gravitino

Photino

SM Neutrino

Sterile Neutrino

Sneutrino

Light DM

Little Higgs DM

Wimpzillas

Cryptobaryonic DM

Q-balls

Mirror Matter

Champs (charged DM)

D-matter

Cryptons

Self-interacting

Superweakly interacting

Braneworld DM

Heavy neutrino

NEUTRALINO

Messenger States in GMSB

Branons

Chaplygin Gas

Split SUSY

Primordial Black Holes

…

“WIMPs”!

“Dark Matter” candidates

L. Roszkowski

WIMP : identity file

- Full name : Weakly Interacting Massive Particle
- Rem : generic name

- Interactions : gravitational, weak nuclear (i.e. « weaker than weak » cross-sections)
- Mass : high enough so as to be cold today
- Life time : stable / sufficiently long to have remained until now
- Relic density : Boltzmann equation + freeze-out
- Nature? SUSY? KK Extra-dimensions? New Physics!

SUSY & LSP…

- Supersymmetry?
- Extension of the Poincaré algebra:
Q |Boson = |Fermion , Q |Fermion = |Boson

{Q, Q} P , [H,Q] = 0

- Unification of gauge couplings, mass hierarchy (Higgs)
- Keep B & L conservation R-parity, R = (-1)3B+L(-1)2S
- SM particles : R = +1 SUSY particles : R = -1

- Extension of the Poincaré algebra:
- R-parity conservation ( if )
- Lightest Supersymmetric Particle stable!
- “Natural” candidate for Dark Matter

- MSSM + R-parity Neutralino :

Extra Universal Dimensions (EUD)

- Kaluza-Klein : extra dimensions
- EUD : all fields propagate in the 5th dim.

Periodical conditions

Momentum quantification

Compactification of extra dim.

at each pt. of 3D space

Dark Matter — related experiments: 2006 World Census

Boulby Mine

Soudan Mine

Frejus

Baikal

LHC

Sudbury

Canfranc

MILAGRO

Gran Sasso

Tevatron

Antares

STACEE

Nestor

VERITAS

Nemo

TIBET, ARGO-YBJ

MAGIC

TACTIC

PACT

GRAPES

Neutrino Telescopes

Observing Satellites

Gamma-ray Telescopes (non-ACT)

Gamma-ray Telescopes (ACTs)

Direct Detection Exps.

HESS

CANGAROO

Colliders

PAMELA

Fermi

IceCube (South Pole)

G. Bertone, Particle DM: what comes next?, Seminar @ Tuebingen U.

DAMA

ZEPLIN

CDMS

Direct detection : Principle & Status

n

Detector (bolometer)

- Collision of a WIMP on a nucleus
- Light
- Heat
- Charge

Background noise,

cryogenics, …

- Gamma Telescopes
- Ground (CANGAROO, HESS, MAGIC, MILAGRO, VERITAS)
- Space : Fermi (GLAST) satellite
- Future Cherenkov Telescope Array?
- Neutrino Telescopes
- Amanda, IceCube
- Antares, Nemo, Nestor
- Km3
- Antimatter Satellites
- PAMELA
- AMS-2
- Other
- Synchrotron
- SZ effect
- Effects on stars…

Indirect Detections

Indirect detection : Dark Matter annihilations

X = DARK MATTER

SM = STANDARD MODEL PARTICLE

Early Universe

Today

X

SM

X

SM

X

SM

X

SM

Rough estimate of the relic density:

Electroweak-scale cross sections can reproduce correct relic density. LSP in SUSY scenarios KK DM in UED scenarios are OK!!

-ray flux from the GC

We can conveniently re-write the-ray flux from the GC as

where J contains all information onAstrophysics

and theDM profileis usually parameterised as

Note : density profile at the very centre may be sharper due to central BH

*Adiabatic* growth of a Black Hole:

BHs as “Annihilation Boosters”!

r-

r-sp

Conserve Mass & Angular Momentum:

sp=

9-2

4-

An intuitive description of Dark Matter “Spikes”

Bertone & Merritt 2005

Evidence for a Supermassive Black Hole at the Galactic Centre

Genzel et al. 2003

M= 3.6 x 106Solar Masses

AnnihilationRadiation

SUSY

(E. Nezri et al, 2001)

To calculate the fluxes, details of annihilations are required. Neutralino annihilations cross-sections can be obtained numerically (DarkSUSY, microMEGA, etc.)

UED

(Servant & Tait, 2002)

Servant & Tait obtained annihilation cross-sections for B(1) particles. In the non-relativistic limit, dependent only on the B(1) mass.

-ray flux from the GC

GB, Servant & Sigl, 2003

Predictions for KK dark matter and neutralinos in the case of a NFW profile without central spike. Fluxes are always below the EGRET normalisation, but within the reach of several future experiments.

Possibility of constraining B(1) mass. Importance of the dark matter density profile.

GB, Servant & Sigl 2003

What about baryonic Dark Matter ??Black Holes? Brown Dwarves? Failed Stars?

Toy derivation of scalar Lagrangian

(J.Virzi, UC Berkeley)

- Heuristic derivation showing how mass terms appear – infinite tower of KK modes

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