1. Dark matter annihilation and the Milky Way diffuse gamma
X.J. Bi (IHEP)
I will briefly introduce a few my recent works related with DM annihilation and indirect detection.

2. Outline Introduction to dark matter annihilation.
GeV excess of diffuse gamma by EGRET and its possible explanation.
Positron excess of HEAT and its possible explanation.

3. Cosmology/astrophysics/particle physics
Particles exists until today is stable particle. SM stable particle are photons, neutrinos, proton, electron. How to present in the universe? If there are new physics, new stable particle, what will occur? Freeze out and form so called DM.

4. High temperature like the high energy colliders produce all kinds of new particles and leave hints in the universe. A simple belief the SM is not the final theory tell us that the there must be DM (matter we do not know) in the universe. In galaxies, high density lead to annihilation again.
From de Boer

5. Evidences — cluster scale
Cluster contains hot gas which is at hydro static equilibrium. It’s temperature follows,
However, X-ray emission measures the temperature and M/Mvisible=20

6. Evidences — cluster scale
Weak lensing measures the distortion of images of background galaxies by the foreground cluster, which measures the cluster mass.
Sunyaev-Zeldovich distortion measures the distortion of CMB passing through cluster, which measure the temperature of the gas and therefore the mass of the cluster.
…other measurements

7. Evidences — galaxy scale
From the Kepler’s law, for r much larger than the luminous terms, you should have v∝r-1/2 However, it is flat or rises slightly.
The most direct evidence of the existence of dark matter.
Corbelli & Salucci (2000); Bergstrom (2000)

8. Evidences — cosmological scale
WMAP measures the anisotropy of CMB, which includes all relevant cosmological information. A global fit combined with other measurements gives
(SN, LSS…) the cosmological
paramters precisely.
mh2=
m=
Spergel et al 2003

9. Non-baryonic DM
From BBN and CMB, it has Bh2= Therefore, most dark matter should be non-baryonic. DMh2=
Non-baryonic dark matter dominates the matter contents of the of the Universe.

10. Energy budget of the universe

11. Problems related with dark matter
What particle form dark matter?
Is there one or many spices of dark matter particles?
What are the dark matter’s quantum numbers?
How and when was it produced?
How to explain the observed value of ?
How is dark matter distributed?
The role in structure formation; How does structure form?
The two sides are closely related: The nature certainly affect the structure formation, ex. hot, cold and warm are different, interacting, decaying dark matter have implications in structure formation.
The evidences come from gravitational effects, which however shed no light on the nature of DM. On the study of effects other than gravity, we will show latter that particle physics and astrophysics/cosmology are closely related.

12. cosmology CMB, LSS, lensing …
Astrophysics, high energy gamma, neutrino
Particle physics
Dark matter
Collider physics

13. Constrains on the SUSY parameter space
The blue stripe is allowed by WMAP
J. Ellis et al (2004)

14. Gamma rays Monoenergetic line Continuous spectrum
A smoking gun of DM ann. The flux is suppressed due to loop production.
Can be used to detect the DM. search for these signal use new instruments.
Larger flux. Need careful analysis of the background

15. Neutrinos from the sun or the earth
Density at the solar center is determined by the scattering, insensitive to the local density
The present data gives
constraints on the
parameter space
IceCube can cover most
paramter space

17. Diffuse gamma rays of the MW
COS-B and EGRET (20keV~30GeV) observed diffuse gamma rays, measured its spectra.
Diffuse emission comes from nucleon-gas interaction, electron inverse Compton and bremsstrahlung. Different process dominant different parts of spectrum, therefore the large scale nucleon, electron components can be revealed by diffuse gamma.

18. GeV excess of spectrum
Based on local spectrum gives consistent gamma in 30 MeV~500 MeV, outside there is excess.
Harder proton spectrum explain diffuse gamma, however inconsistent with antiproton and position measurements.

19. Hard proton or electron injection index

20. Contribution from DM
In this work it is suggested that the excess is explained by dm annihilation The six regions can all be explained well. They fit the normalization factors and give these results.

21. Fit the spectrum B~100 Fi,j ----- Enhancement by substructures
Adjust the propagation parameters
The fit the egret data by nomornalizing the flux of the bkg and the flux of DM. they find the DM flux should be enhanced a factor of aobut 100 and the nomorlization factor for bkg is between 2 to 0.5. in our work we calculate the absolute the flux of DM and bkg and try to explaind the data directly. The dm flux can be enhanced after taking into account of the subhalos. The bkg is not need to be nomorlized.

22. The SUSY factor The integrated flux due to different threshold energy.
Points are different SUSY model

23. With and without subhalos
The dm distribution. When we take the subhalo into account we get the flux of dm annihilation. This curve is the flux from smooth dm and thses are taking the subhalos into acount. They enhance the flux by 1~2 orders of magnitude.

24. Calculate cosmic rays
Adjust the propagation parameter to satisfy all the observation data and at the same time satisfy the egret data after adding the dark matter contribution
Adjust the propagation while satisfy the observations of b/c, electron, proton.

25. Results of different regions
The total spectrum fit the data excellently. The agreement between data and theoretical prediction is perfect.

26. HEAT and positron excess
HEAT found a positron excess at ~10 GeV B~
In another heat exp the posi fraction is also observed an excess above 8 gev. It is explained by dm annihilaton. The data is also fitted and the dm annhilation need a boost factor about 100~1000.

27. Enhancement by subhalos
The average density (for annihilation) is improved with subhalos.
The corresponding positron flux is improved.

28. Result
The positron fraction can be explained still need a boost factor of about 2~3

29. Uncertainties in positron flux
Large uncertainties from propagation
Uncertainties by the realization of the subhalos distribution.
We think that is not a problem again due to the large uncertainties in the theoretical calculation. Another uncertainty is we do not how the subhalos is distributed and we only give the average positron flux.

30. Conclusion
In any new physics beyond SM predicting new stable particle predicts the DM in the universe and the existence of DM is confirmed by astrophysics observations.
Taking the contribution from DM annihilation into account the EGRET data can be explained perfectly. (Without DM it is difficult to explain the GeV excess even there are large uncertainties of cosmic ray propagation).
Positron excess in HEAT can also be explained by adding contribution from DM annihilation.
Both the EGRET data and HEAT require DM subhalos with very cuspy profile.

31. Unified model of dark matter and dark energy
Possible candidates of dark energy are the cosmological constant or a scalar field --- the quintessence field (a dynamical fundamental scalar field).
The motivation is to build a unified model of dark matter and dark energy in the framework of supersymmetry.
requiring a shift symmetry of the system, the quintessence is always kept light and the potential is not changed by quantum effects. If is the LSP, it is stable and forms DM.

32. Shift symmetry and interaction
To keep the shift symmetry the quintesssence field can only coupled with matter field derivatively. We consider the following interactions and derive their supersymmetric form:
Stellar evolution, SN87A, familon search

33. Non-thermal production of quintessino
WIMP  quintessino + SM particles (WIMP=weakly interacting massive paricle)
quintessino SM
WIMP
Since the interaction of quintessino is usually suppressed by Planck scale, it is generally called superWIMP.
e.g. Gravitino LSP
quintessino
LKK graviton
106

34. OK Candidates of NLSP EM had Brhad  O(0.01) Brhad  O(10-3)
WIMP  quintessino + SM particles
EM, had. cascade
 change CMB spectrum
 change light element
abundance predicted by BBN
Charged slepton, sneutrino
Or neutralino/chargino
105 s  t  107 s
neutralino/chargino NLSP
slepton/sneutrino NLSP
BBN EM
had
Brhad  O(0.01)
Brhad  O(10-3) OK
Charged slepton NLSP are allowed by the model

35. Effects of the model
Suppress the matter power spectrum at small scale (flat core and less galaxy satellites).
Faraday rotation induced by quintessence.
Suppress the abundance of 7Li.
The lightest super partner of SM particles is stau.

36. Look for heavy charged particles
A charged scalar particle with life time of 105 s  t  107 s and mass 100 GeV< M < TeV is predicted in the model.
High energy comic neutrinos hit the earth and the heavy particles are produced and detected at L3C/IceCube
Due to the R-parity conservation, always
two charged particles are produced
simultaneously and leave two parallel
tracks at the detector.

37. Production at colliders
If is the LSP of SM, all SUSY particles will finally decay into and leave a track in the detector.
Collecting these , we can study its decay process. (We can even study gravity at collider.)
LHC/ILC can at most produce
Buchmuller et al 2004
Kuno et al., 2004
Feng et al., 2004

38. Conclusion
In the CDM scenario, LSS form hierarchically. The MW is distributed with subhalos.
Taking the contribution from DM annihilation into account the EGRET data can be explained perfectly. (Without DM it is difficult to explain the GeV excess even there are large uncertainties of cosmic ray propagation).
Positron excess in HEAT can also be explained by adding contribution from DM annihilation.
Both the EGRET data and HEAT require DM subhalos with very cuspy profile.
A DM-DE unified model requires stau being the NLSP (gravitino model). Make different phenomenology.