Download - Dark matter annihilation and detection
![Page 1: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/1.jpg)
Dark matter annihilation and detection
X.J. Bi (IHEP)
2006.8.28
![Page 2: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/2.jpg)
Outline
• Annihilation signals from the subhalos and the detection.
• GeV excess of diffuse gamma by EGRET and its possible explanation.
• Positron excess of HEAT and its possible explanation.
• An interesting dark matter model which predicts a heavy charged stable particle.
![Page 3: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/3.jpg)
Subhalos in the MW halo • The DM annihilation flux is pro
portional to the DM density square
• A wealth of subhalos exist due to high resolution simulations.
Moore et al
2v
![Page 4: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/4.jpg)
The first generation object
Diemand, Moore & Stadel, 2005:• Depending on the nature of
the dark matter: for neutralino-like dark matter, the first structures are mini-halos of 10-6 M⊙.
• There would be zillions of them surviving and making up a sizeable fraction of the dark matter halo.
• The dark matter detection schemes may be quite different!
![Page 5: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/5.jpg)
-rays from the subhalos
Reed et al, MNRAS357,82(2004) -rays from subhalos-rays from subhalos
-rays from smooth bkg-rays from smooth bkg
source
sun GC
![Page 6: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/6.jpg)
Statistical results
•The curves are due to different author’s simulations.
•The threshold is taken as 100 GeV.
•The susy factor is taken an optimistic value for neutralino mass between 500 GeV and 1TeV.
•Results are within the field of view of ARGO.
![Page 7: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/7.jpg)
Instruments with large field of view and their
sensitivities
• GLAST
• ARGO/HAWC
![Page 8: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/8.jpg)
Complementary capabilities
ground-based space-based ACT EAS Pair angular resolution good fair good duty cycle low high high area large large small field of view small large large+
can reorient energy resolution good fair good, with smaller systematic
uncertainties
Gamma ray detection from DM annihilation
my estimateHAWC~0.04ICRAB
![Page 9: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/9.jpg)
Sensitivity at ARGO( 95% C.L.)
![Page 10: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/10.jpg)
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.
![Page 11: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/11.jpg)
GeV excess of spectrum• Based on local s
pectrum 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.
![Page 12: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/12.jpg)
• Hard proton or electron injection index
![Page 13: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/13.jpg)
Contribution from DM
![Page 14: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/14.jpg)
Fit the spectrum
• B~100
• Fi,j -----
Enhancement by substructures
Adjust the propagation parameters
![Page 15: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/15.jpg)
With and without subhalos
dlrsol
mo )(..
2cos
![Page 16: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/16.jpg)
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
![Page 17: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/17.jpg)
Results of different regions
![Page 18: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/18.jpg)
HEAT and positron excess• HEAT fou
nd a positron excess at ~10 GeV
B~100-1000
![Page 19: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/19.jpg)
Enhancement by subhalos
• The average density (for annihilation) is improved with subhalos.
• The corresponding positron flux is improved.
![Page 20: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/20.jpg)
Result • The positron fraction can be explained still
need a boost factor of about 2~3
![Page 21: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/21.jpg)
Uncertainties in positron flux• Large uncertainties from propagation
• Uncertainties by the realization of the subhalos distribution.
![Page 22: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/22.jpg)
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.
QiQQ q
~),(ˆ
Q~
CQQ
![Page 23: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/23.jpg)
Shift symmetry and interaction• To keep the shift symmetry the quintesssence fiel
d can only coupled with matter field derivatively. We consider the following interactions and derive their supersymmetric form:
FQFM
c
plQ
~L
FQ
Q~~ 5
~~ L
..|ˆ 2 cheQc gV
L iCQQ ˆˆ
![Page 24: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/24.jpg)
quintessinoquintessinoSMSM
101066
Non-thermal production of quintessinoNon-thermal production of quintessino
WIMP WIMP quintessino + SM particles quintessino + SM particles ((WIMP=weakly interacting massive paricle)WIMP=weakly interacting massive paricle)
WIMPWIMP Since the interaction of quintessino is usually suppressed by Planck scale, it is generally called superWIMP.
e.g. Gravitino LSPe.g. Gravitino LSP quintessinoquintessino LKK gravitonLKK graviton
![Page 25: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/25.jpg)
Candidates of NLSPCandidates of NLSP
neutralino/chargino NLSPneutralino/chargino NLSP slepton/sneutrino NLSPslepton/sneutrino NLSP
BBNBBN
EMEM
hadhad
BrBrhadhad O(0.01) O(0.01) Brhad O(10-3)
WIMP WIMP quintessino + SM particles quintessino + SM particles
Charged slepton, sneutrinoCharged slepton, sneutrinoOr neutralino/charginoOr neutralino/chargino
EM, had. cascade
change CMB spectrum
change light element
abundance predicted by BBN
Charged slepton NLSP are allowed by the modelCharged slepton NLSP are allowed by the model
101055 s s t t 10 1077 s s
![Page 26: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/26.jpg)
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.
![Page 27: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/27.jpg)
Look for heavy charged particles
• A charged scalar particle with life time of 101055 s s t t 10 1077 s 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.
![Page 28: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/28.jpg)
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
~
~
~
~
65 1010 ~ ~Buchmuller et al 2004
Kuno et al., 2004
Feng et al., 2004
![Page 29: Dark matter annihilation and detection](https://reader036.vdocuments.mx/reader036/viewer/2022062314/56813dff550346895da7d9f6/html5/thumbnails/29.jpg)
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.