Cosmological and astrophysical probes of dark matter annihilation Institute for Cosmic Ray Research, University of Tokyo Kazunori Nakayama J.Hisano, M.Kawasaki, K.Kohri and KN, Phys.Rev.D79,063514(2009)[0810.1892] J.Hisano, M.Kawasaki, K.Kohri and KN, Phys.Rev.D79,043516(2009)[0812.0219] M.Kawasaki, K.Kohri and KN, to appear in Phys.Rev.D [0904.3626] J.Hisano, KN, and M.J.S.Yang, Phys.Lett.B678,101(2009)[0905.1552] ACP
[email protected] IPMU (2009/07/02)
Contents • First part • PAMELA/Fermi results & constraints on DM annihilation scenario
• Second part • Neutrino signals from GC • Diffuse gamma-ray background
First Part : Quick Summary
Energy content of the Universe after WMAP
What is the dark matter? Can it be detected?
Collider Direct detection DM-nucleon Scattering Indirect detection DM annihilation Cosmic Ray Signals
Detecting dark matter signal DM + DM → e± , γ, p¯, ν, . . . ±
e
γν We are here
0.4 0.3
+
-
Positron fraction !(e ) / (!(e )+ !(e ))
PAMELA observation
+
0.2
0.1
0.02
Muller & Tang 1987
excess in cosmic-ray positron flux
MASS 1989 TS93 HEAT94+95 CAPRICE94 AMS98 HEAT00 Clem & Evenson 2007 PAMELA
0.01 0.1
1
10
100
Energy (GeV)
Adriani et al.,arXiv:0810.4995
ux ha ver eas rd ng ia-
on cal ea ng
de da ux ya ata
were observed, with the highest energy event at 2.3 TeV. The total background is also shown in the figure as the open triangles and is a combination of unresolved protons, unidentified c-rays and atmospheric secondary electrons produced in the material (,4.5 g cm22) above the instrument. ATIC becomes background limited for electrons only above several teraelectronvolts.
ATIC/PPB-BETS observations
excess in electron+positron flux
1,000
Ee3.0dN/dEe (m−2 s−1 sr−1 GeV2)
s gy in e
100
ATIC BETS, PPB-BETS HEAT AMS 10
10
100 Energy (GeV)
1,000
Figure 3 | ATIC results showing agreement with previous data at lower energy and with the imaging calorimeter PPB-BETS at higher energy. The J.Chang al. Nature the electron differential energy spectrum measured by ATICet(scaled by E3) at(2008)
Fermi observation
Inconsistent with ATIC results. Still there may be excess. Fermi LAT collaboration, 0905.0025
E3 dN/dE (GeV2 m-2 s-1 sr-1)
HESS observation ! E ± 15%
102
ATIC PPB-BETS Kobayashi H.E.S.S. H.E.S.S. - low-energy analysis Systematic error Systematic error - low-energy analysis Broken power-law fit
102
103
Consistent with Fermi results.
Energy (GeV)
HESS collaboration, 0905.0105
Dark Matter : Decay or Annihilate Decaying DM DM need not be completely stable. DM lifetime with τ ∼ 1026 sec can explain PAMELA.
nDM ∼ 10−29 cm3 s−1 Flux ∝ τ
Annihilating DM DM may have weak scale annihilation cross section. −24 −23 3 −1 !σv" ∼ 10 − 10 cm s Cross section with can explain PAMELA. 2 −29 3 −1 Flux ∝ nDM "σv# ∼ 10
cm s
Positron fraction
Total flux
[GeV2 m−2 s−1 sr−1 ]
χχ → µ+ µ− : mχ = 1.2TeV, "σv# = 1.2 × 10−23 cm3 s−1
Positron fraction
Total flux
[GeV2 m−2 s−1 sr−1 ]
χχ → τ + τ − : mχ = 1.5TeV, "σv# = 3.5 × 10−23 cm3 s−1
It is important to investigate
Relation to other signals
• Gamma-rays from Galactic center • Diffuse extragalactic gamma-rays • Anti-protons • Synchrotron radiation γν • Neutrinos from Galactic center
e±
DM DM # Μ$ Μ! , NFW profile 10!20
DM DM # Τ$ Τ! , NFW profile 10!20
GC!VLT
GC!VLT
10!22
GR!Γ GC!Γ
10!24
M
ρDM (r) ∼ 1/r
GC!radio !26
10
102
A
EL
Σv in cm3 !sec
Σv in cm3 !sec
ASgr dSph!Γ EL
M PA
103
10!22
$ !
10!24
GC!radio !26
10
102
DMGC!radio DM # Μ Μ , isothermal profile GR!Γ Sgr dSph!Γ
10
104
10!20
LA
E
GR!Γ A L Sgr dSph!Γ
Sensitively depends on DM halo profile.
E
M
Σv in cm !sec
10!22
PA
10!22
3
Σv in cm3 !sec
M PA
103
DM mass in GeV DMGC!radio DM # Τ$ Τ! , isothermal profile GC!Γ
GC!Γ
!20
Sgr dSph!Γ GC!Γ GR!Γ
104
DM mass in GeV
PA
Constraints on DM ann models.
10!24
10!24
ρDM (r) ∼ 1/(1 + r2 )
10!26
10!26
102
103 DM mass in GeV
104
102
103 DM mass in GeV
104
G.Bertone et al., 0811.3744
What we have done : • Neutrino-induced muon flux from Galactic center
• Diffuse extragalactic gamma-rays from dark matter annihilation
Both give useful constraints on DM models, rather insensitive to DM halo profile J.Hisano, M.Kawasaki, K.Kohri and KN, arXiv:0812.0219 M.Kawasaki, K.Kohri and KN, arXiv:0904.3626 J.Hisano, KN, and M.J.S.Yang, arXiv:0905.1552
DM DM # Μ$ Μ! , NFW profile 10!20
DM DM # Τ$ Τ! , NFW profile 10!20
GC!VLT
GC!VLT
M PA
10!22
GR!Γ GC!Γ
10!24
A
EL M A
Σv in cm3 !sec
Σv in cm3 !sec
ASgr dSph!Γ EL P
10!22
GC!Γ GR!Γ 10!24
GC!radio
GC!radio
!26
!26
10
10 2
10
10
3
10
4
102
DM mass in GeV
M
GC!Γ 10!20
A EL
GR!Γ A Sgr dSph!Γ L
E
M PA
PA
Σv in cm !sec
10!22
10!22
3
Σv in cm3 !sec
104
DMGC!radio DM # Τ$ Τ! , isothermal profile
GR!Γ Sgr dSph!Γ
10!20
103 DM mass in GeV
DMGC!radio DM # Μ$ Μ! , isothermalGC!Γ profile
e
Sgr dSph!Γ
10!24
10!26
10!24
10!26 102
103 DM mass in GeV
104
102
103 DM mass in GeV
104
G.Bertone et al., 0811.3744
DM DM # Μ$ Μ! , NFW profile GC!VLT
Σv in cm3 !sec
ASgr dSph!Γ EL
M PA
10!22
10!20
ν
GR!Γ GC!Γ
10!24
GC!VLT
A
EL M A
Σv in cm3 !sec
10!20
DM DM # Τ$ Τ! , NFW profile
P
10!22
GC!Γ GR!Γ 10!24
GC!radio
GC!radio
!26
!26
10
10 2
10
10
3
10
4
102
DM mass in GeV
M
GC!Γ 10!20
A EL
GR!Γ A Sgr dSph!Γ L
E
M PA
PA
Σv in cm !sec
10!22
10!22
3
Σv in cm3 !sec
104
DMGC!radio DM # Τ$ Τ! , isothermal profile
GR!Γ Sgr dSph!Γ
10!20
103 DM mass in GeV
DMGC!radio DM # Μ$ Μ! , isothermalGC!Γ profile
e
Sgr dSph!Γ
10!24
10!26
10!24
10!26 102
103 DM mass in GeV
104
102
103 DM mass in GeV
104
G.Bertone et al., 0811.3744
DM DM # Μ$ Μ! , NFW profile GC!VLT
Σv in cm3 !sec
ASgr dSph!Γ EL
M PA
10!22
10!20
ν
GR!Γ GC!Γ
10!24
GC!VLT
P
10!22
10!24
GC!radio
!26
!26
10
10 2
10
10
3
10
4
102
DM mass in GeV
M
104
DMGC!radio DM # Τ$ Τ! , isothermal profile GC!Γ
GR!Γ Sgr dSph!Γ
10!20
103 DM mass in GeV
DMGC!radio DM # Μ$ Μ! , isothermalGC!Γ profile 10!20
A EL
GR!Γ A Sgr dSph!Γ L
E
M PA
PA
Σv in cm !sec
10!22
10!22
3
Σv in cm3 !sec
Sgr dSph!Γ GC!Γ GR!Γ
GC!radio
e
diffuse γ
A
EL M A
Σv in cm3 !sec
10!20
DM DM # Τ$ Τ! , NFW profile
10!24
10!26
10!24
10!26 102
103 DM mass in GeV
104
102
103 DM mass in GeV
104
G.Bertone et al., 0811.3744
Second part : Neutrino Flux J.Hisano, M.Kawasaki, K.Kohri and KN, Phys.Rev.D79,043516(2009)[0812.0219] J.Hisano, KN, and M.J.S.Yang, Phys.Lett.B678,101(2009)[0905.1552]
Neutrino Signal from DM Annihilation + − ¯ χχ → W W , bb, l l , . . . +
−
→ e , γ, p¯, ν, . . . ±
Ritz, Seckel (88),Kamionkowski (90),... Bertone,Nezri,Orloff,Silk (04), Yuksel,Horiuchi,Beacom,Ando(07)
Interaction inside the Earth detector
ν
µ
from GC Earth
Search for up-going muons Limits from Super-K
SK limit on upward muon flux from GC direction x 10
-12
Baksan Limit IMB Limit Kamiokande Limit MACRO Limits Super-K Limits
0.12
-2
-1
Flux Limit (cm sec )
0.1
0.08
0.06
0.04
0.02
0
0-5
0-10
0-15
0-20
0-25
0-30
Cone Half Angle From Galactic Center (Degrees)
S.Desai et al., Phys.Rev.D70,083523 (2004)
Muon flux from DM Nµ =
!
dFνµ f (Eνµ ) dEνµ dEνµ
µ
(a) Neutrino flux from DM: dFνµ dEνµ
(b) Probability of νµ → µ :
f (Eνµ )
SK detector
ν
Rock
(a) Neutrino flux from GC dFνµ dEνµ
! # (ν ) R! ρ2! " dNF µ = !σv"F J∆Ω 2 8πm dEνµ F
(ν ) dNF µ
Neutrino spectra : DM halo profile dependent part :
dEνµ
J∆Ω =
matter annihilaTypical value ications to some is performed inof J∆Ω ns.
!
=
! i
dΩ ∆Ω
"
Pνi νµ
!
l.o.s.
(ν ) dNF i
dEνi
#
Eνi =Eνµ
Neutrino oscillation " #2 dl(ψ) ρ(l) R! ρ! 2
!J2 "Ω ∆Ω NFW isothermal
5◦ 10◦ 15◦ 20◦ 25◦ 6.0 10 14 17 20 1.3 4.3 8.0 11 15
!J1 "Ω ∆Ω
5◦ 10◦ 15◦ 20◦ 25◦
(b) Probability of f (Eνµ ) ∼
!
νµ → µ dσνµ p→µX (rock) R(Eµ ) dEµ np dEµ
G2F s Cross section : ∼ ∝ Eνµ π
Number density of proton in the rock : −3 n(rock) = 1.3N cm A p
Muon range : R(Eµ )
νµ
µ W
N
N
!
Energy loss of muon in matter Dutta, Reno, Sarcevic, Seckel, Phys.Rev.D63,094020 (2001)
dEµ = −α(Eµ ) − β(Eµ )Eµ dX 2 −1 α(E ) ! 2 MeVcm g Ionization loss : µ −6 2 −1 β(E ) ! 10 cm g µ Radiative loss :
(Brems, pair creation, ...)
Typical propagation distance : Eµ ∼ 1 km(Eµ /1TeV) Rµ ∼ α(Eµ )ρrock
Muon range in the rock Propagation distance [km]
10
all loss ionization loss
∝
1
0.1 10
100
E
1000
10000
Muon energy [GeV]
Eµ ! 1 TeV Eµ ! 1 TeV
Rµ ∼ 1 km(Eµ /1TeV) deviation from linearity
Probability of f (Eνµ ) ∼
νµ → µ
!
dσνµ p→µX (rock) R(Eµ ) dEµ np dEµ
f (Eνµ ) ∝
G2F s ∼ ∝ Eνµ π 2 Eνµ
∝ Eµ
Higher energy neutrinos are more likely converted into muon
Monochromatic neutrino : χχ → ν ν¯ is constrained more severely than + − − secondary neutrino : χχ → µ µ , µ → νµ ν¯e e
Limits from SK : Annihilation into left-handed leptons is not favored. − + Annihilate into left handed leptons (ν ν¯ + lL lR ) − + Annihilate into right handed leptons (lR lL )
J.Hisano, M.Kawasaki, K.Kohri, KN (2008)
!σv"J∆Ω [cm3 s−1 ]
νµ ν¯µ
Gray : current SK bound
(for θ = 5 ) ◦
+ −
µ µ !σv"J∆Ω [cm3 s−1 ]
Contour : Muon flux (×10−15 cm−2 s−1 )
Total muon flux Nµ =
!
dFνµ f (Eνµ ) dEνµ dEνµ
∝ m−2 χ
Nµ ∼ const.
!σv"J∆Ω [cm3 s−1 ]
νµ ν¯µ
Contour : Muon flux (×10−15 cm−2 s−1 ) PAMELA & Fermi
(for θ = 5 ) ◦
Total muon flux
+ −
µ µ !σv"J∆Ω [cm3 s−1 ]
Gray : current SK bound
Nµ =
PAMELA & Fermi
!
dFνµ f (Eνµ ) dEνµ dEνµ
∝ m−2 χ
Nµ ∼ const.
Lesson from neutrino Construct a DM model which fits PAMELA/Fermi data (either ann or decay) Check if your model produce monochromatic neutrinos with similar rate or not If yes, your model may conflict with SK bound irrespective of DM density profile Check carefully the SK bound!
Σv in cm3 !sec
DMGC!radio DM # Τ$ Τ! , isothermal profile GC!Γ 10!20 GR!Γ LASgr dSph!Γ
E
AM
P
!22
10
10!24
10!26 102
103
104
DM mass in GeV
G.Bertone et al., 0811.3744
Σv in cm3 !sec
DMGC!radio DM # Τ$ Τ! , isothermal profile GC!Γ 10!20 GR!Γ LASgr dSph!Γ
E
AM
P
!22
10
10!24
10!26 102
103
104
DM mass in GeV
G.Bertone et al., 0811.3744
P.Maede et al., 0905.0480
Σv in cm3 !sec
DMGC!radio DM # Τ$ Τ! , isothermal profile GC!Γ 10!20 GR!Γ LASgr dSph!Γ
E
AM
P
!22
10
10!24
10!26 102
103
104
DM mass in GeV
G.Bertone et al., 0811.3744
P.Maede et al., 0905.0480
Neutrino constraint becomes standard.
Σv in cm3 !sec
DMGC!radio DM # Τ$ Τ! , isothermal profile GC!Γ 10!20 GR!Γ LASgr dSph!Γ
E
AM
P
!22
10
Caution : This figure considers only secondary neutrino from tau decay.
10!24
10!26 102
If DM annihilates into line neutrino, constraint becomes 10 10 more DM mass in GeV stringent. 3
4
G.Bertone et al., 0811.3744
P.Maede et al., 0905.0480
Neutrino constraint becomes standard.
Possible improvement at SK High-energy neutrino-induced muons are detected through Cherenkov light Energy of each muon is not measured However, SK can distinguish muon events by event shape : shower and non-shower Higher energy muons more likely observed as showering muon DM-originated neutrinos more likely produce shower events than atmospheric neutrinos
Simulation
3 kind of muon events :
10000
Through-going shower mu
Showering Non-showering
dN/d(logE)
Stopping
5000
Through-going nonshower mu Stopping mu Probability for shower
0 1
10
2
3
10 10 E! (GeV)
10
S.Desai et al., Astropart.Phys.29,42 (2008)
4
10
5
atmos : Honda et al.,2005
-1
-2 -1
-1
Flux [GeV cm s sr ]
10-7
DM atmos BG
-8
10
-9
10
10-10 10-11 10-12 1 10
2
10
3
Eν[GeV]
10
4
10
atmos : Honda et al.,2005
-1
-2 -1
-1
Flux [GeV cm s sr ]
10-7
DM atmos BG
-8
10
Non-shower -9 10 muon
Shower muon
10-10 10-11 10-12 1 10
2
10
3
Eν[GeV]
10
4
10
atmos : Honda et al.,2005
-1
-2 -1
-1
Flux [GeV cm s sr ]
10-7
DM atmos BG
-8
10
Non-shower -9 10 muon
Shower muon
10-10 10-11 10-12 1 10
2
10
3
Eν[GeV]
10
4
10
Shower muon events contain relatively large contribution from DM-produced neutrino
Ratio between Shower muon and Total muon
atmospheric : Nµshower /Nµtotal ! 0.12
!σv"J∆Ω [cm3 s−1 ]
νµ ν¯µ
Gray : current SK bound
(for θ = 5 ) ◦
+ −
µ µ !σv"J∆Ω [cm3 s−1 ]
Contour : Muon flux −15 −2 −1 (×10 cm s )
A factor improvement is expected on the annihilation cross section May soon reach to PAMELA/Fermi region? Hisano, KN,Yang 0905.2075
!σv"J∆Ω [cm3 s−1 ]
νµ ν¯µ
Contour : Muon flux −15 −2 −1 (×10 cm s ) PAMELA & Fermi
+ −
!σv"J∆Ω [cm3 s−1 ]
µ µ
Gray : current SK bound
(for θ = 5 ) ◦
A factor improvement is expected on the annihilation cross section PAMELA & Fermi
May soon reach to PAMELA/Fermi region? Hisano, KN,Yang 0905.2075
Comments on IceCube Huge detector High statistics Located at South Pole cannot see Galactic center through upward muons Use downward muons? Atmospheric muon BG is 10^6 larger than DM signal
A planned extension : DeepCore Future: Deep Core Primary purpose : better sensitivity •To improve low E event efficiency -- indirect DM search, atm. ! osc, etc.. on low-energy neutrino • total 6 strings (75 m apart)
cf. nominal strings: 125 m apart Inner detector with • 60 DOMs/string denser instrumentation -- high QE DOMs (~ 35% more light yield) -- DOMs are densely spaced
Use original detector • 4 ! as detector: muon veto
-- veto surrounding bottom inner core (6 DC + 7 IC)
Remove atmospheric muon BG
-- explore southern sky as well as Galactic Center
Dark09, Christchurch, New Zealand
IceCube Talk Seo, Stockholm Univ.
27
S.Seo, Talk at Dark2009
Expected sensitivity of DeepCore (5yr) 5000
1000 Boost
500
"
$
Μ #Μ
5 Σ Detection 2 Σ Limit
100 50
PAMELA
Fermi 10
500 1000 1500 2000 2500 3000 3500 M Χ !GeV"
Spolyar, Buckley, Freese, Hooper, Murayama, 0905.4764
Summary DM interpretation of PAMELA/Fermi Confirm/constrain by other signals Neutrino-induced muon Flux Useful constraints on annihilating/decaying DM. Shower/non-shower separation may be a useful way to extract DM information. SK III, DeepCore, KM3NeT
Second Part II : Diffuse gamma-rays
M.Kawasaki, K.Kohri and KN, to appear in Phys.Rev.D [0904.3626]
Gamma-Ray Flux
Gamma-Ray Flux Galactic center
Gamma-Ray Flux Galactic center
Extra Galactic diffuse
Continuum Gamma-Rays from DM ann. Internal Brems.
+
χ
e
Final state charged particle always emit photon. + −
χχ → l l + − χχ → l l γ
γ χ
−
e
Cascade decay + −
+
χχ → τ τ , W W
−
→ hadrons(π , π , ρ, . . . ) ±
0
2γ
Extra-Galactic component
Ullio, Bergstrom, Edsjo, Lacey (2002)
Dominant contribution is summation over the DM ann. in external clustering objects
γ We are here
!
dΦγ . dE
"
ext
!σv" = 8π
ρ¯2m m2χ
#
dz(1 + z)3 dN γ 2 ∆ (z) ! H(z) dE
∆ (z) : Enhancement factor 2
(∆2 (z) = 1 : homogeneous DM)
∆ (z) ∝ 2
!
dn(z) dM M dM
!
drρ2M (r)
Number of clustering objects : Press-Schechter theory Universal DM halo profile Press, Schechter (1974) (Moore, NFW, ...) Sheth, Mo, Tormen (2001)
2 ∆ (z) Enhancement factor
Moore 10
7
2
! (z)
106 10
1 ρ(r) ∼ 1.5 r (1 + r1.5 )
Moore NFW Burkert
NFW
5
1 ρ(r) ∼ r(1 + r)2
104 10
Burkert
3
0
1
2
3
4
5 z
6
7
8
9 10
1 ρ(r) ∼ (1 + r)(1 + r2 )
About 10^5-10^6 enhancement for DM annihilation rate
◦ ◦ 10 < |b| < 90 Gamma-rays from
Extragalactic component is comparable to Galactic component
±
e
τ
±
±
µ
W±
M.Kawasaki, K.Kohri, KN, 0904.3626
Constraints on annihilation cross section
Cuspy profile : extragalactic is weaker than GC bound Cored profile : extragalactic is stronger than GC bound Fermi will soon make the bound stronger
Effects of Inverse Compton scattering CMB photon e± + γCMB → e± + γ
Profumo, Jeltema,0906.0001 Belikov, Hooper, 0906.2251
+ −
τ τ
Second peak around Eγ(IC) ∼ γe2 ECMB
!m "2 DM ∼ 0.1 GeV 1 TeV
More stringent constraint
Summary DM interpretation of PAMELA/Fermi Confirm/constrain by other signals, as Neutrino-induced muon Flux Useful constraints on annihilating/decaying DM. SK III, DeepCore, KM3NeT Gamma-ray Flux Both Galactic and extra-Galactic gamma-rays may be significant in DM ann scenario. Fermi
Back-up Slides
Astrophysical source Pulsar (single or sum) Gamma-ray burst Sum of all pulsars
Hooper, Blasi, Serpico, arXiv:0810.1527 Profumo, arXiv:0812.4457 K.Ioka, arXiv:0812.4851
Geminga pulsar
Hooper, Blasi, Serpico, arXiv:0810.1527
DM or Astrophysics?
Imin
Imax − Imin δ= Imax + Imin
Anisotropy in CR flux
Imax
Point source
!
K(E) ∼ 0.01% 1 kpc ∼ R Rc
"!
E 1 GeV
"0.6
Anisotropy from nearby Pulsar
i m r e F
r y 5
Hooper, Blasi, Serpico, arXiv:0810.1527
!=2, MED diffusion setup, ST model B0355+54
Vela Monogem (B0656+14)
Positron Fraction
Loop I
0.1
Cygnus L. Geminga
0.01 10
100
1000
10000
Energy [GeV]
S.Profumo, arXiv:0812.4457
Press-Schechter theory dn = dM
!
" # " # 2 2 ρ¯m δc 1 dσ(M ) δc − exp − 2 . 2 π M σ(M ) dM 2σ (M )
M : halo mass fraction of mass in halos heavier than M
1
10
-1
σ(M ) : dispersion of density field δc ∼ 1.686 : critical overdensity
fraction of mass in each mass interval
1 σ (M ) = 2π 2 2
10
z=0 z=2 z=4
-2
2
4
Ullio et al. (2002)
6
8
10
12
14
log 10 (M / M !! )
!
W 2 (kM )P (k)k 2 dk
Predict number of collapsed objects with mass M