1. Dark Matter: A Mini Review
Jin Min Yang
杨 金 民
中国科学院理论物理研究所
Hong Kong

2. Outline Evidence of Dark Matter Candidates of Dark Matter
Experiments for Dark Matter
SUSY Dark Matter
Outlook

3. 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 (imply baryon mass density ~ 4 )
Supernovae probe: Hubble diagram indicate DM and DE in universe
Colliding clusters: observation of colliding clusters from bullet cluster

4.   0.3 GeV/cm3
V  220 km/s

5. candidates 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

6. 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

7. 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

8. Universe cools: n=nEQe-m/T
WIMP correct relic density of DM
Thermal equilibrium
  ff
Universe cools: n=nEQe-m/T
10-34 秒
Freeze out ~
0.1
BBN
1 秒
1013 秒
1018 秒

9. Note: so far all DM information is from astro observation !
(gravity effects of DM)
Nature (identity & property) of DM particle
experiments

10. 3、Experiments for Dark Matter
3.1 Astrophysical experiments
direct detection c c p e+ n g _
indirect detection
land-based
high altitude
space-based
3.2 Collider experiments (LHC, ILC)

11. 3.1 Astrophysical experiments
(a) direct detection

12. (b) indirect detection (anti-particle)

13. (c) indirect detection (photon)
ARGO-YBJ
W. de Boer

14. (d) indirect detection (neutrino)

15. 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

16. 4. SUSY Dark Matter

17. neutralino (WIMP)
LSP
gravitino (SuperWIMP)

18. 4.1 Neutralino (WIMP) Dark Matter
(a) Allowed parameter space:
Baer,Tata (2008)

19. (b) Astrophysical expts:
Baer,Tata (2008)

20. (c) Collider expts (LHC, ILC):
Baer,Tata (2008)
LHC
Baltz et al (2006)

21. (d) Collider + Astrophysical expts:
Baer,Tata (2008)
Baer, et al (2004)

22. 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)

23. (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)

24. 5. Outlook
Collider Experiments
WIMP Property

25. LHC (“best case scenario”)
ILC
LHC (“best case scenario”)
Planck
(~2010)
WMAP
(current)
LCC1
Battaglia (2005)

26. 谢谢！