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Dark Matter - 中国科学院理论物理研究所

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Dark Matter - 中国科学院理论物理研究所
Dark Matter: A Mini Review
Jin Min Yang
杨 金 民
中国科学院理论物理研究所
2008.7.23 Hong Kong
Outline
• Evidence of Dark Matter
• Candidates of Dark Matter
• Experiments for Dark Matter
• SUSY Dark Matter
• Outlook
1、 Evidence of Dark Matter
• Galactic clusters: need DM to bind them (1930s, Zwicky)
• Galaxy rotation curves: need a diffuse halo of DM (1970s, Rubin &Ford)
• Gravity lensing: strong and weak lensing show DM in universe
• Hot gas in clusters: need DM to bind the hot gas
• CMB: CMB power spectrum show composition of universe (WMAP)
• Large scale structure formation: a universe composed of CDM and DE
• BBN: light elements abundances agree with observation if
nB/n ~ 610-10 (imply baryon mass density ~ 4 )
• Supernovae probe: Hubble diagram indicate DM and DE in universe
• Colliding clusters: observation of colliding clusters from bullet cluster
  0.3 GeV/cm3
V  220 km/s
What we know about DM so far ?
•
•
•
•
neutral
cold (part of it can be warm)
weak interaction (with itself and with ordinary matter)
profile (around us 0.3GeV/cm3 V  220 km/s)
Identity of DM particle ?
candidates
2、Candidates of Dark Matter
Q-balls: topological solitons in QFT (Coleman, Kusenko)
Neutrinos: sterile (Kusenko, 2006)
Black hole remnants: tiny BHs produced in early universe
Wimpzillas: massive beasts (Kolb et al)
Axions: Peccei-Quinn solution to strong CP
WIMPs: lightest neutralino in SUSY with R-parity
lightest KK excitations in EDT with KK-parity
lightest T-odd particle in LHT with T-parity
SuperWIMPs: gravitino in SUSY with R-parity
axino—fermionic partner of axion
lightest KK graviton in EDT
Why WIMP is popular and favored ?
(1) naturally predicted in new physics models
(SUSY, Extra-dimension, LHT)
• lightest neutralino in SUSY with R-parity
• lightest KK excitations in extra-dimension
• lightest T-odd particle in LHT with T-parity
(2) naturally give the correct relic density of DM
WIMP
correct relic density of DM
Thermal equilibrium
  ff
Universe cools: n=nEQe-m/T
Freeze out
10-34 秒
~ 0.1
BBN
1 秒
1013 秒
1018 秒
Note: so far all DM information is from astro observation !
(gravity effects of DM)
Nature (identity & property) of DM particle
experiments
3、Experiments for Dark Matter
3.1 Astrophysical experiments
• direct detection
• indirect detection
land-based
high altitude
space-based



3.2 Collider experiments (LHC, ILC)
_
p

e+ n

3.1 Astrophysical experiments
(a) direct detection
(b) indirect detection (anti-particle)
(c) indirect detection (photon)
ARGO-YBJ
W. de Boer
(d) indirect detection (neutrino)
3.2 Collider study of dark matter
Tevatron (now)
LHC (2008)
ILC
(???)



model-dependent study
model-independent study (possible)
model-dependent study
Birkel,Matchev,Perelstein, 2004
4. SUSY Dark Matter
LSP
neutralino (WIMP)
gravitino (SuperWIMP)
4.1 Neutralino (WIMP) Dark Matter
(a) Allowed parameter space:
Baer,Tata (2008)
(b) Astrophysical expts:
Baer,Tata (2008)
(c) Collider expts (LHC, ILC):
LHC
Baer,Tata (2008)
LHC
Baltz et al (2006)
(d) Collider + Astrophysical expts:
Baer,Tata (2008)
Baer, et al (2004)
4.2 Gravitino (SuperWIMP) Dark Matter
(1) Interaction:
(gaugino & gauge boson)
(fermions)
Suppressed by  E/M* (extremely weak !)
(2) Relic density:
(thermal)
(late-decay of NLSP)
Weinberg (1982)
Cyburt, Ellis, Fields, Olive (2003)
Kawasaki, Kohri, Moroi (2005)
Feng, Rajaraman, Takayama, Su (2003)
(3) Astrophysical expts:
Null results ! (due to extremely weak interaction)
(4) Collider expts:
Detect NLSP (meta-stable)
NLSP (stau)
SM particle
LHC
Hamaguchi, kuno, Nakaya, Nojiri (2004)
Feng, Smith (2004)
5. Outlook
Collider Experiments
WIMP Property
ILC
LHC (“best case scenario”)
WMAP
(current)
Planck
(~2010)
LCC1
Battaglia (2005)
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