Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 1
Dark Matter shining by Galactic gamma rays and its possible implications for the LHC
From EGRET excess of diffuse Galactic gamma rays• Determination of WIMP mass• Determination of WIMP halo (= standard halo + DM ring)
Confirmation:• Rotation curve• Canis Major/Monoceros stream• Gas flaring
PREDICTIONS• for LHC (if SUSY)• for direct searches• for solar neutrinos
Ingredientsto this analysis
Gamma ray spectrafor BG + DMAParticle Physics
Cosmology
Astrophysics
23%DM, thermalhistory of WIMPs Annihilation cross sectionTidal disruption of dwarfs
CosmicsGamma rays
AstronomersRotation curveTidal streamsGas flaring
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 2
• 95% of the energy of the Universe is non-baryonic 23% in the form of Cold Dark Matter
• Dark Matter enhanced in Galaxies and Clusters of Galaxies but DM widely distributed in halo-> DM must consist of weakly interacting and massive particles -> WIMP’s
• Annihilation with <σv>=2.10-26 cm3/s, if thermal relic
From CMB + SN1a + surveys
DM halo profile of galaxycluster from weak lensing
If it is not darkIt does not matter
What is known about Dark Matter?
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 3
Colliding Clusters Shed Light on Dark Matter
http://www.sciam.com/
August 22, 2006
Observations with bullet cluster:
•Chandra X-ray telescope shows distribution of hot gas•Hubble Space Telescope and others show distribution of Dark Matter from gravitational lensing•Distributions are clearly different after collision-> •dark matter is weakly interacting!
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 4
Do we have Dark Matter in our Galaxy?
RotationcurveSolarsystem
rotation curveMilky Way
1/r
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 5
Simple 3-Komponent Galaxy: p+e+Wimps
Interactions:
p+e <->H electromagnetic x-sectionp+p -> X strong x-section: 10-25 cm2
p+W -> p+W x-section:<10-43 cm2 (direct DM searches)W+W -> X x-section: 10-33 cm2 (Hubble expansion)
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 6
Expansion rate of universe determines WIMP annihilation cross section
Thermal equilibrium abundance
Actual abundance
T=M/22Co
mo
vin
g n
um
ber
d
ensi
ty
x=m/TGary Steigmann/ Jungmann et al.
WMAP -> h2=0.1130.009 -> <v>=2.10-26 cm3/s
DM increases in Galaxies:1 WIMP/coffee cup 105 <ρ>. DMA (ρ2) restarts again..
T>>M: f+f->M+M; M+M->f+fT<M: M+M->f+fT=M/22: M decoupled, stable density(wenn Annihilationrate Expansions- rate, i.e. =<v>n(xfr) H(xfr) !)
Annihilation into lighter particles, likequarks and leptons -> 0’s -> Gammas!Only assumption in this analysis:WIMP = THERMAL RELIC!
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 7
Example of DM annihilation (SUSY)
Dominant + A b bbar quark pairSum of diagrams should yield<σv>=2.10-26 cm3/s to getcorrect relic density
Quark fragmentation known!Hence spectra of positrons,gammas and antiprotons known!Relative amount of ,p,e+ known as well.
f
f
f
f
f
f
Z
Z
W
W 0
f~
A Z
≈37 gammas
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 8
IF DM particles are thermal relics from early universethey can annihilate with cross section as large as <v>=2.10-26 cm3/s which implies an enormous rate of gamma raysfrom π0 decays (produced in quark fragmentation) (Galaxy=1040 higher rate than any accelerator)
Expect significant fraction of energetic Galactic gamma rays to come from DMA in this case.Remaining ones from pCR+pGAS-> π0+X , π0->2γ
(+some IC+brems)This means: Galactic gamma rays have 2 componentswith a shape KNOWN from the 2 BEST studied reactionsin accelerators: background known from fixed target exp. DMA known from e+e- annihilation (LEP)
Conclusion sofar
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 9
R
Sundisc
Basic principle for indirect dark matter searches
R
Sun
bulge
disc
From rotation curve:
Forces: mv2/r=GmM/r2
or M/r=const.for v=cons.and(M/r)/r2
1/r2
for flat rotation curve
Expect highest DM densityIN CENTRE OF GALAXY
Divergent for r=0?NFW profile1/rIsotherm profile const.
IF FLUX AND SHAPE MEASURED INONE DIRECTION, THEN FLUX ANDSHAPE FIXED IN ALL (=180) SKY DIRECTIONS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
R1
THIS IS AN INCREDIBLE CONSTRAINT, LIKE SAYING I VERIFYTHE EXCESS AND WIMP MASS WITH 180 INDEPENDENT MEAS.
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 10
Instrumental parameters:
Energy range: 0.02-30 GeVEnergy resolution: ~20%Effective area: 1500 cm2
Angular resol.: <0.50
Data taking: 1991-1994
Main results: Catalogue of point sourcesExcess in diffuse gamma rays
EGRET on CGRO (Compton Gamma Ray Observ.)
Data publicly available from NASA archive
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 11
Two results from EGRET paper
Enhancement in ringlike structure at 13-16 kpc
Called “Cosmic enhancement
Factor”Excess
101 Eγ GeV
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 12
Background + signal describe EGRET data!
Blue: background uncertainty
Background + DMA signal describe EGRET data!
Blue: WI MP mass uncertainty
50 GeV
70
I CI C
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 13
Analysis of EGRET Data in 6 sky directions
A: inner Galaxy (l=±300, |b|<50)B: Galactic plane avoiding AC: Outer Galaxy
D: low latitude (10-200)
E: intermediate lat. (20-600)F: Galactic poles (60-900)
A: inner Galaxy B: outer disc C: outer Galaxy
D: low latitude E: intermediate lat. F: galactic poles
Total 2 for all regions :28/36 Prob.= 0.8 Excess above background > 10σ.
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 14
Fits for 180 instead of 6 regions180 regions:80 in longitude 45 bins4 bins in latitude 00<|b|<50
50<|b|<100
100<|b|<200
200<|b|<900 4x45=180 bins >1400 data points. Reduced 2≈1 with 7% errorsBUT NEEDED IN ADDITION to 1/r2 profile, substructurein the form of 2 doughnut-likerings in the Galactic disc!
ONE RING COINCIDES WITHORBIT FROM CANIS MAJORDWARF GALAXY which loosesmass along orbit by tidal forces
OTHER RING coincides with H2 ring
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 15
2002,Newberg et al. Ibata et al, Crane et al. Yanny et al.
1/r2 profile and rings determined from inde-pendent directions
xy
xz
Expected Profile
v2M/r=cons.and
(M/r)/r2
1/r2
for const.rotation
curveDivergent for
r=0?NFW1/r
Isotherm const.
Dark Matter distribution
Halo profile
Observed Profile
xy
xz
Outer Ring
Inner Ring
bulge
tota
lDM
1/r2 halodisk
Rotation Curve
Normalize to solar velocity of 220 km/s
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 16
Halo density on scale of 300 kpc
Sideview Topview
Cored isothermal profile with scale 4 kpc Total mass: O(1012) solar masses
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 17
Halo density on scale of 30 kpc
Sideview Topview
Enhancement of inner (outer) ring over 1/r2 profile 6 (8).Mass in rings 0.3 (3)% of total DM
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 18
How does DM substructure formfrom tidal disruption of dwarf
galaxies?
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 19
The Milky Way and its satellite galaxies
Canis Major
Tidal force ΔFG 1/r3
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 20
Tidal streams of dark matter from CM and Sgt
CM
Sgt
Sun
From David Law, Caltech
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 21
Canis Major Dwarf orbits from N-body simulationsto fit visible ring of stars at 13 and 18 kpc
Canis Major leaves at 13 kpc tidal stream of gas(106 M☉ from 21 cm line), stars (108 M☉ ,visible), dark matter (1010 M☉, EGRET)
Movie from Nicolas Martin, Rodrigo Ibatahttp://astro.u-strasbg.fr/images_ri/canm-e.html
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 22
N-body simulation from Canis-Major dwarf galaxy
prograde retrograde
Ob
serv
ed
sta
rsR=13 kpc,φ=-200,ε=0.8
Canis Major (b=-150)
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 23
Gas flaring in the Milky Way
no ring
with ring
P M W Kalberla, L Dedes, J Kerp and U Haud, http://arxiv.org/abs/0704.3925
Gas flaring needs EGRET ring with mass of 2.1010M☉!
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 24
Enhancement of inner (outer) ring over 1/r2 profile 6 (8).Mass in rings 0.3 (3)% of total DM
Inner Ring coincides with ring of dust and H2 -> gravitational potential well!
H2
4 kpc coincides with ring ofneutral hydrogen molecules!H+H->H2 in presence of dust->grav. potential well at 4-5 kpc.
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 25
Objections against DMA interpretation
Rotation curves in outer galaxy measured with different method than inner rotation curve. Can you combine? Also it depends on R0.
Answer: first points of outer RC have same negative slope as inner RC so no problem with method. Change of slope seen for every R0.
R0=8.3 kpc
R0=7.0v
R/R0
Innerrotationcurve
Outer RC
Black hole at centre: R0=8.00.4 kpc
Sofue &Honma
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 26
Bergstrom et al. astro-ph/0603632, Abstract:
we investigate the viability of the model using the DarkSUSY package to compute the gamma-ray and antiproton fluxes. We are able to show that their (=WdB et al) model is excluded by a wide margin from the measured flux of antiprotons.
Problem with DarkSUSY (DS):1) Flux of antiprotons/gamma in DarkSUSY: O(1) from DMA. However, O(10-2) from LEP data Reason: DS has diffusion box with isotropic diffusion -> DMA fills up box with high density of antiprotons2) Priors of DARKSUSY.(and other propagation models as well): a) static galactic magnetic fields are negligible b) gas is smoothly distributed c) propagation in halo and disk are the sameALL priors likely wrong and can change predictions for DM searches by ORDER OF MAGNITUDE (and still ok with all observations!)
Do antiproton data exclude interpretation of EGRET data?
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 27
it is shown that Galactic cosmic rays can be effectively confined throughmagnetic reflection by molecular clouds,Chandran, 1999
Another propagation model including static magnetic fields and gas clouds and anisotropic diffusion
Galactic magnetic field (A0)
Fast propagation along regular field lines will reduceantiproton flux from DMA, while grammage and lifetimeare determined by trapping in magnetic fields
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 28
Escape time of cosmic rays andgrammage (distance x density)
10Be (t1/2 = 1.51 Myr) is cosmicclock: lifetime of cosmics 107 yrs.
In GALPROP: by large haloIn CHANDRAN: by long trapping.
B/C=secondary/prim.determines grammage (smaller than disc!)In GALPROP: by large haloIn CHANDRAN: by reflectingmolecular clouds
B/C determines grammage
10Be/9Be determines escape time
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 29
CHANDRAN model GALPROP model
Preliminary results from GALPROP with isotropic and anisotropic propagation
Summary: with fast propagation perp. to disc (e.g. by convection,fast diffusion or static magnetic fields) one reduces contributionof charged particles from DMA by large factor and can be consistent with B/C and 10Be/9Be
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 30
What about Supersymmetry?
Simplest model: mSUGRA with 5 parameters:m0, m1/2, tan β, A0, sign µ
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 31
EGRET excess interpreted as DM consistent with WMAP, Supergravity and electroweak constraints
Bulk
Too largeboostfactorfor EGRETdata
StauLSP
h<114
LSP largely Bino DM may be supersymmetric partner of CMB
Charginos, neutralinos and gluinos light
WMAP
EGRET
Stau coannihilation
mA resonance
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 32
mSUGRA cross sections
tot [pb]
tan=50 A0=0
Main production channels:Contributions of different production channelsnormalized to the total SUSY cross section
Total mSUGRA cross section(LO) K
NLO =1.3-1.7
MET+ Njets+ Nleptons
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 33
mSUGRA topologies
<MET>
Heff= MET+ET jets
+ETleptons
mSUGRA averaged observables in m0-m
1/2 plane
<Njets> ET>30 GeV
<N>muons PT>10 GeV/c
<PT>
highest muon <E
T > highest jet
Different event topology in different regions according to masses and couplings..
tan=50 A0=0CMS FAMOS
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 34
Detector performanceDetector performance
Inclusive trigger efficiencies in mSUGRA plane L1 Stream
143
292e 17
Jet+MET 88+45Jets1(1,2,3,4) 177,86,70
.......
LL thresholds, GeV
12e
HLT Stream LL thresholds, GeV197
e 292e 17
Jet+MET 180+123Jets1(1,2,3,4) 657,247,113
.........
12
L1 with respect to MC HLT with respect to L1
Main trigger streams for SUSY
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 35
Celestial bodies collect DM in their cores by their high density.Annihilation can result in flux of HIGH energy neutrinos from sun (from b-decays or from Z-decays).
Neutrinos can be detected by large detectors,like Super-Kamiokande, Amanda, Ice-Cube, Baksanby the charged current interactions with nuclei,which yields muons in the detectors.
Indirect DM detection from solar neutrinos
EG
RET
SUN
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 36
WIMPs elastically scatter off nuclei => nuclear recoilsMeasure recoil energy spectrum in target
Direct Detection of WIMPs
0
0
H,Z
EGRET?CDMS
XENON10
If SUSY particle spectrumknown, elastic scattering X-section can be calculated
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 37
Clustering of DM
An artist picture of what we should see if oureyes were sensitive to 3 GeV gamma rays and wewere flying with 220 km/s through the DM halo
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 38
8 physics questions answered SIMULTANEOUSLY if WIMP = thermal relic
• Astrophysicists: What is the origin of “GeV excess” of diffuse
Galactic Gamma Rays?• Astronomers: Why a change of slope in the galactic rotation
curve at R0 ≈ 11 kpc? Why ring of stars at 13 kpc? Why ring of molecular hydrogen at 4 kpc? Why S-shape in gas flaring? • Cosmologists: How is DM annihilating?A: into
quark pairs
How is Cold Dark Matter distributed?• Particle physicists: Is DM annihilating as expected in
Supersymmetry?
A: DM substructure
A: DM annihilation
A: standard profile + substructure
A: Cross sections perfectly consistent with mSUGRA for light gauginos, heavy squarks/sleptons
Wim de Boer, Karlsruhe
HEP2008, Chile, Jan. 8, 2008 39
Summary
>>10σ EGRET excess shows intriguing hint that:
WIMP is thermal relic with expected annihilation into quark pairs
SPATIAL DISTRIBUTION of annihilation signal is signature for DMAwhich clearly shows that EGRET excess is tracer of DM by fact thatone can construct rotation curve and tidal streams from gamma rays.
DM becomes visible by gamma rays from fragmentation(30-40 gamma rays of few GeV pro annihilation from π0 decays)
Results rather model independent, since only KNOWN spectral shapes of signal and background used, NO model dependent calculations of abs.fluxes.Different shapes or unknown experimental problems may change the gamma ray flux and/or WIMP mass, BUT NOT the distribution in the sky.
DM interpretation strongly supported independently by gas flaring
DM interpretation perfectly consistent with Supersymmetry
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