Transcript Folie 1

Indirect Dark Matter Searches in the
Light of ATIC, FERMI, EGRET and PAMELA
Annihilation products from
dark matter annihilation:
Gamma rays
(EGRET, FERMI)
Positrons (PAMELA)
Antiprotons (PAMELA)
e+ + e-
(ATIC, FERMI, HESS, PAMELA)
Neutrinos
(Icecube, no results yet)
e-, p drown in cosmic rays?
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
1
Expansion rate of universe determines
thermal relic annihilation cross section
Thermal equilibrium abundance
Comoving number density
Actual abundance
T>>M:
f+f->M+M; M+M->f+f
T<M:
M+M->f+f
T=M/22: M decoupled, stable density
(wenn annihilation rate  expansion rate,
i.e. =<v>n(xfr)  H(xfr) !)
WMAP -> h2=0.1130.009 ->
<v>=2.10-26 cm3/s
DM increases in Galaxies:
1 100 GeV WIMP/coffee cup 105 <ρ>.
DMA (ρ2) restarts again..
T=M/22
Only assumption:
WIMP = STABLE THERMAL RELIC!
x=m/T
G. Steigman
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
2
Example of DM annihilation (SUSY)


f 
~
f
f 
A
W 


f 

W 
f 
0
f
Z
Z
≈37
gammas
Z
Dominant
 +   A  b bbar quark pair
Sum of diagrams should yield
<σv>=2.10-26 cm3/s to get
correct relic density
Wim de Boer, Karlsruhe
f
Quark-fragmentation known!
Hence spectra of positrons,
gammas and antiprotons known!
Relative amount of ,p,e+ known
as well.
SUSY09, Northeastern Univ., Boston, June 5, 2009
3
The PAMELA Satellite Experiment (launched July 2006)
Transition
Radiation
Detector
Resurs Dk1
Satellite
20.5
cm2sr
~10 T
(removed for
tech.reasons)
1.2 m
Anticoincidence
Shield
Silicon
Tracker and
Permanent
Magnet
Si-W
Electromagnetic
Calorimeter
~450 kg
Bottom
Scintillator
Neutron Detector
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
300 - 600 km
Time of Flight
Counters
4
PAMELA, positron and antiproton measurements
Positron fraction
Nature 458:60,2009,arXiv:0810.4995
Positrons: excess
Wim de Boer, Karlsruhe
Antiproton/proton ratio
(O. Adriani et. al., PRL (2009)[0810.4994])
+prelim. new data, Boezio, Pamela-WS 2009
Antiprotons: NO excess
SUSY09, Northeastern Univ., Boston, June 5, 2009
5
ATIC Balloon experiment, Nature 2008
Kaluza-Klein DM decays to
lepton pairs ->peak in electron
spectrum with tail from energy losses
KK x-section  Y4
so mainly decay to
leptons and u-quarks
Baltz, Hooper, hep-ph/0411053
Baltz, Zurek, 0902.0593
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
6
FERMI measures GeV gamma rays + electrons

e e–
+
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
7
FERMI electron spectrum: NO BUMP at 600 GeV
Simulating the LAT response to a spectrum with an “ATIC-like” feature:
Alexander Moiseev
Pamela workshop
May 11, 2009
This demonstrates that the Fermi LAT would have been able to reveal
“ATIC-like” spectral feature with high confidence if it were there.
Energy resolution is not an issue with such a wide feature
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
8
Cherenkov telescopes measure TeV gamma rays
HESS
MAGIC
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
9
HESS, May 2009
Electron spectrum falls off above 1 TeV
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
10
Interpretations
Many possibilities:
Background from hadronic showers
with large electromagnetic component
 astrophysical sources
 pulsars


positron acceleration in SNR
locality of sources
 dark matter annihilation



leptophilic?
bound states?
Kaluza-Klein
Wim de Boer, Karlsruhe
-> ap->0
-> apulsar
-> asec
-> aSNR
-> aDMA
SUSY09, Northeastern Univ., Boston, June 5, 2009
11
Truth?
Depends on whom you ask!
My assumption:
|Data>= ap->0 |Background> + aDMA |DMA>
+ asec |SNR> + alocal |SNR(x)> + apulsar |Pulsar>
Unitarity must be fulfilled. However, will now
show that each component has enough uncertainty
to saturate observations
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
12
Cosmic ray spectra
<2
orders of magn.
E-3.3
E-2.7
E-3.0
3 orders of magn.
e- mainly from SNR
e+ mainly p+p   e
p+p 3p+p+X
1 TeV
Lipari, PAMELA Workshop, 2009
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
13
G.F. 5000 cm2 sr
Exposure > 3 yrs
dP/P2 ~ 0.004  2.5 TV, p rejection = 10-5 (ECAL +TRD); Δx=10µm; Δt=100ps
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
14
2009
Wim de Boer, Karlsruhe
2010
SUSY09, Northeastern Univ., Boston, June 5, 2009
15
AMS to be launched in 2010
AMS
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
16
AMS on ISS
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
17
The AMS superconducting Magnet at CERN (2008)
He Tank
Coils
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
18
Magnet inside vacuum tank
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
19
Current Status (May 2009)
The magnet is at 1.7 K
The system is fully leaktight to superfluid helium
The magnet is being commissioned
and other detector components will be
integrated in 2009. Flight to ISS 2010.
Note: all components have been integrated in2008 in
spare vacuum vessel and have been thoroughly
tested. They worked as expected.
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
20
The Alpha Magnetic Spectrometer on ISS
AMS
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
21
AMS proton contamination
S. Haino, INFN Perugia
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
22
What a little dash of protons can do!
Gregory Tarle at PPC09, 20.5.09
Moskalenko & Strong
PAMELA claims p rejection of 10-5. CAUTION! This is not verified using
independent technique in flight.
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
23
ap->0 :GEANT proton/electron separation
single diffractive x-section
pp/ppbar exp.
FERMI Geant
10 mb
Ferro, Sobol,
Totem-Note 2004-5
M. Schmanau, Karlsruhe
100
1000 GeV
√s
Hard to simulate p+p->p+0+X (diff. scatt.)
Looks very much like electron. Only TRD can distinguish.
Especially dangerous for photon detectors with “converter”
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
24
aDMA:DM interpretation of FERMI e-data
TeV DM decaying to low scale
particle, which can only
decay leptonically
TeV DM forms bound state
to get large boost factor via
Sommerfeld enhancement
Models e.g. by
Arkani-Hamed,Finkbeiner,Slatyer,Weiner
arXiv:0810.0713
Nomura and Thaler,
arXiv:0810.5397
Fit by Bergstrom et al.arXiv:0905.0333
See also talk by G. Kane, tuesday
on wino DM with non-thermal history
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
25
Conclusion sofar
ap->0 : hadronic showers with large
electromagnetic component
(e.g. from diffractive scatt.)
cannot be excluded as background
and can be large enough to explain
rise in electrons and positrons.
Need TRD to suppress this background
aDMA : can find non-standard models,
but need large boost factors
to find signal in ELECTRONS
and LEPTOPHILIC model to obtain
small contribution to ANTIPROTONS
What about astrophysical explanations?
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
26
asec :Secondary positron acceleration in SNR
P. Blasi, arXiv:0903.2794
e+
It can work!
e-
Idea:
secondary particles are produced
in SNR and might as well be
accelerated there ->.
source of HE secondary positrons
and electrons
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
27
aloc :3-component e- sources: spiral arm, disc, local
Shaviv et al., arXiv:0902.0376,2009
e loose energy rapidly
(dE/dt  E2),
hence they are “local”
3-component structure
explains e-spectrum,
Pamela/Fermi anomalies
and why nothing in pbar
It can work!
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
28
apulsar :Pulsars
D. Grasso et al., arXiv:0905.0636
See also: Yuksel, Kistler, Stanev, 2008;
Aharonian, Atoyan and Völk, 1995;
Kobayashi et al., 2004)
More in talk by
Profumo on monday
Note: rotating strong
B-field-> synch. rad->
+B->(e+ + e-) -> N ->
N+B->N(e+ + e-)
So pulsars strong source
for (e+ + e-), NO pbar.
But:escape fract. unknown.
Wim de Boer, Karlsruhe
It can work!
SUSY09, Northeastern Univ., Boston, June 5, 2009
29
How much DMA signal can still be in pbar?
F. Donato, D.
Maurin, P. Brun,
T. Delahaye and P.
Salati,
Phys.Rev.Lett.102:07
1301,2009
Answer:
in isotropic propagation models very little.
In anisotropic prop. models significant pbar
contribution from DMA allowed!
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
30
Present models: isotropic propagation
Isotropic propagation leads to
“propagation enhancement”:
of charged particles: trapping of charged
particles in “leaky” Galaxy for a long time->
Flux of gamma rays from DMA 
Flux of antiprotons in such propagation models,
Although we KNOW from LEP that fragmentation
gives many more photons than antiprotons
Is this right?
Not nessarily!
CONVECTION = negligible with isotropic
propagation in contrast to observation
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
31
Propagation including Convection
This does not allow for
significant convection, since
CR‘s do not return to disc->
too little secondary production
from CR hitting gas in disc
CRs propagation can be
described by diffusion and
convection, very much like a
drop of ink inside streaming
water (with water
velocity=convection velocity)
Present models use isotropic
propagation, i.e. same diffusion
constant in halo and disc.
Wim de Boer, Karlsruhe
HOWEVER, significant
convection observed by ROSAT
Radiaactive clocks like 10Be
determine time from source to
Sun (107 yrs) Need slow
diffusion in disc, but particles
in halo drift to outer space
with convection
With convection little flux of
charged particles from DMA,
since particles drift away.
SUSY09, Northeastern Univ., Boston, June 5, 2009
32
NATURE 452, 17. April 2008,
“Blown away by cosmic rays”, D.Breitschwerdt
Cosmic Rays (CR) form a plasma. If blowing in a given direction,
it will take other particles with it, thus exerting pressure.
This CR pressure drives all halo particles to intergalactic space,
thus reducing strongly the flux of charged particles from DMA.
Fit to ROSAT data,
Everett et al.
NGC 253
arXiv:0710.3712v1
Convection of few 100 km/s not allowed in GALPROP, since
particles will not return to disc and produce secondaries.
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
33
Best evidence for convection from absence of
511 keV emission from the Galactic disc
INTEGRAL/SPI observed bright
511 keV emission from the
bulge of the Milky Way (1.3 x
1043 positrons injected per
second), but almost nothing
from disc
Sources of low energy positrons
(low energy, else they do not
annihilate):
Radioactive nuclei from SNIa
and other stellar objects, see
Prantzos,arXiv:0809.2491
Wim de Boer, Karlsruhe
Explanation:
DiffusionE so MeV
positrons do not diffuse.
Convection independent
of energy, so they can
disappear by convection
from disc to halo. Here
no electrons to annihilate.
SUSY09, Northeastern Univ., Boston, June 5, 2009
34
Propagation including “ROSAT” convection
“ROSAT” convection
GALPROP convection
propagation
enhancement:
DM: GC
(Bergstrom, Edsjo, Gustafsson
and Salati, JCAP, astro-ph/0602632)
Summary: preferred propagation perp. to disk can reduce
contribution of charged particles from DMA by large factor
and can be consistent with B/C and 10Be/9Be
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
35
Secondary production (B/C) and
cosmic clocks (10Be/9Be)
B/C determines grammage
10Be/9Be
B/C=secondary/prim.determines
grammage (smaller than disk!)
In diffusion dom.: by large halo
In convection dom.: by slow
diffusion in disk.
Wim de Boer, Karlsruhe
determines escape time
10Be
(t1/2 = 1.51 Myr) is cosmic
clock: lifetime of cosmics 107 yrs.
In diffusion dom.: by large halo
In convection dom.: by slow diff.
SUSY09, Northeastern Univ., Boston, June 5, 2009
36
Diffuse gamma rays
Great advantage of pointing to the
source and propagation is
„straightforward“ without dependence
on magnetic field and diffusion.
Astrophysical point sources can be
pinpointed and subtracted.
For newest FERMI data on DMA:
see Winer on Wednesday, June 10
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
37
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
38
Diffuse gamma rays from FERMI
20% EGRET
100%
Published
FERMI data
on VELA pulsar:
agrees within errors
with EGRET at 3 GEV
astro-ph/0812.2960
Why diffuse spectrum disagrees 100% with EGRET at 3 GeV
while VELA spectrum agrees with EGRET at 3 GeV within 20%?
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
39
Summary
Charged particles do not point to source, so many indistinguishable
sources possible. Also propagation uncertainties large.
|Data>= ap->0 |Background> + aDMA |DMA>
+ asec |SNR> + alocal |SNR(x)> + apulsar |Pulsar>
At present all coeff. between 0 and 1 possible.
Need additional data to distinguish:
a) LHC will constrain aDMA
b) FERMI gamma rays will tell about astrophysical
sources and DMA via diffuse gamma rays
(propagation “straightforward”)
c) Positron fraction will distinguish between alocal
and (asec ,apulsar)
d) AMS-02 with TDR will tell about background
Wim de Boer, Karlsruhe
SUSY09, Northeastern Univ., Boston, June 5, 2009
40