PAMELA/ATIC cosmic-ray
anomalies and new physics
1. Apr. 2009
@実験理論共同研究会「LHC が切り拓く新しい物理」

Fuminobu Takahashi(IPMU, Univ. of Tokyo)
Collaborators: Chen, Hamaguchi, Komatsu, Nojiri, Shirai, Torii, Yanagida
arXiv:0809.0792, 0810.4110, 0811.0477, 0811.3357, 0812.4200,0901.1915, 0901.2168, 0902.4770

Plan of talk
1.Introduction
2.PAMELA and ATIC/PPB-BETS anomalies
3.Dark Matter Models
Annihilation and decay of dark matter
Hidden gauge boson
4.Conclusion

Introduction

Dark Matter
How can we know the presenceof “dark” matter?

Gravity

It's not just a good idea.
It's the law!

Dark Matter
The presence of DM has
been firmly established.

ΩDM ∼ 0.2
CMB observation
Rotation curves
Structure formation
Big bang nucleosynthesis(taken from WMAP webpage)Many

Dark Matter Candidates

Must be electrically neutral, long-lived and cold.
No DM candidates in SM.

SUSY
LSP is long-lived if R-parity is a good symmetry.
e.g.) neutralino, gravitino, right-handed sneutrino, axino, etc..

Little Higgs, UED, etc.
The lightest T-parity/KK-parity particles

OthersQ-ball, saxion, moduli, sterile ν,etc...

Dark matter may not be completely dark.
ColliderDirect detection
Indirect search:annihilation/decay of dark matter

Uncertainty
in propagation/clumpiness.

(http://pamela.roma2.infn.it/index.php)

Dark matter may not be completely dark.
ColliderDirect detection

STE!
?
B
Indirect search:erBuPannihilation/decay of dark mattertP
a/nCgiIsT
AM&DdAnLuEofM
PA aveUncertainty
hin propagation/yamclumpiness.
(http://pamela.roma2.infn.it/index.php)

PAMELA and ATIC/PPB-BETS

Launched on the 15th of June 2006.
An altitude between 350 and 610 Kmwith an inclination of 70°.
Expected to operate at least by Dec.
2009 (3 years).

Energy range:
Positron: 50 MeV - 270 GeV
Antiproton: 80 MeV - 190 GeV

geometricacceptance
TOF (S1)CARD
CAT
TOF (S2)

trackingsystem(6 planes)

magnetspectrometerB

anticoincidenceCAS

TOF (S3)Z

calorimeter~16.3 X0
~0.6 lI

YX

scint. S4
neutrondetector

protonantiproton

This is what PAMELA observed.
0.4July2006Feb. 2008

0.3+

-Positron fraction !(e ) / (!(e )+ !(e ))Positron fraction

0.2+

151,672 e9,430 e+
in 1.5-100GeV

0.1

0.02

Muller & Tang 1987
MASS 1989
TS93
HEAT94+95
CAPRICE94
AMS98
HEAT00Clem & Evenson 2007
PAMELA

0.01
0.1

1

10100

Energy (GeV)

Adriani et al, arXiv:0810.4995

To appear
tomorrow inNature

PAMELA found an excess-0.2

Primary source!

+0.3+

Positron fraction !(e ) / (!(e )+ !(e ))in the positron fraction!

0.1

charge-dependent
solar modulation

0.02

PAMELA0.01
110

Adriani et al, arXiv:0810.4995

Expectedb.g.100
Energy (GeV)Polar Patrol Balloon (PPB)PPB-BETS: 2004
http://ppb.nipr.ac.jp/Advanced Thin Ionization
Calorimeter (ATIC)ATIC-1: 2001
ATIC-2: 2003
ATIC-4: 2008
http://atic.phys.lsu.edu/aticweb/index.html

ATIC found excess+in the (e + e ) spectrum
PPB-BETS ATIC

Epeak =600-700GeV

Chang et al, Nature Vol.456 362 2008 [ATIC]Torii et al, arXiv:0809.0760 [PPB-BETS]

HESS

HESS

The PAMELA data suggests that there is alocal primary source for positrons.
The positron spectrum needs to be a very
hard one.
Then, we should expect that the electron
spectrum may be also significantly modified at
E > 100GeV.

Maybe, the PAMELA and ATIC/PPB-BETS
excesses arise from the same origin.

Possible candidates
Dark Matter decay or annihilation
Nearby pulsars, gamma-ray burst,microquasars, or unknown astro.
source.
Profumo 0812.4457, Ioka 0812.4851
Kawanaka,Ioka,Nojiri 0903.3782

DM or pulsars?
The annihilation/decay of DM is often accompanied withanti-protons, gamma-rays, neutrinos. The observation on
those particles will be complementary check.
If the positron/electron excess is dominated by a few
nearby pulsars, we may be able to observe directional
anisotropy of O(0.1-1)%.

Need more data!!

Dark Matter Models

Dark matter must account forDark matter must account for1)the observed electron + positron flux witha hard spectrum,Dark matter must account for1)the observed electron + positron flux witha hard spectrum,2)while avoiding anti-proton (neutrino, gamma)
overproduction.

Electron + Positron flux:
Propagation through the galactic magnetic field is describedby a diffusion equation∂fe∂
2= K(E)∇ fe (E, x) +[b(E)fe (E, x)] + Q(E, x)∂t∂E

diffusionenergy loss

sourceelectron/positron

Dark MatterphotonCross-section,Decay rate∂∇ · [K(E, !r)∇fe ] +[b(E, !r)fe ] + Q(E, !r) = 0∂E

diffusiondiffusion K(E)= K0

energy b(E) =loss
E0 = 1 GeV

sourceq =energy loss!

EE0E2,E0 τE"δ

source,L[kpc]

τE = 10 sec
16dNe (E)Q(E, !r) = q · (ρ(!r)) ·dEp
1 mX τ X!σv"
2m2X

20 kpcfor decay
for annihilation

Annihilating DM scenario!σv" = O(10−23) cm /sec
3m ∼ 600 − 800 GeV(for unit boost factor)

Decaying DM scenario
Lifetime: τ ∼ 10 sec
26m ∼ 1.2 − 1.6 TeV

Annihilating DM scenario
The mass should be (600-800)GeV.
The needed annihilating cross section is!σv" = O(10−23) cm /sec
3! "σv#thermal $ 3 × 10−26cm /sec
3cf. thermal relic abundance:Ωdm h ∼ 0.1
2!

"σv#f o3 × 10−26 cm3 s−1"−1

In the thermal case, some enhancement is necessary.
Or DM may be non-thermally produced.

Annihilating DM scenario
The mass should be (600-800)GeV.
The needed annihilating cross section is!σv" = O(10−23) cm /sec
3! "σv#thermal $ 3 × 10−26

cm /sec
3cf. thermal relic abundance:Ωdm h ∼ 0.1
2!

"σv#f o3 × 10−26 cm3 s−1"−1In the thermal case, some enhancement is necessary.
Or DM may be non-thermally produced.

Boost factor:
The DM distribution may be clumpy, according
to the N-body simulation.
2
Γ = !σv" nDM

can be enhanced.

Sommerfeld effect:Arkani-Hamed et al, 0810.0713

Breit-Wigner tailIbe, Murayama, Yanagida, 0812.0072

Decaying DM scenario
Dark matter particle withMass:m ∼ 1.2 − 1.6 TeV

Lifetime: τ ∼ 10 sec
26

Independent of the boost factor.
The longevity of DM is a puzzle,
especially if the mass is above 1TeV.

The lightest particle charged under
an approximate discrete symmetry(LSP, LKP) Gravitino, sneutrino, neutralino
Chen, FT 08
Takayama-Yamaguchi 00
Ibarra-Tran 08,
Ishiwata-Matsumoto-Moroi 08,09

Hamaguchi FT, Yanagida 09

A hidden-sector particle
A composite particle

Chen, FT, Yanagida 0809.0792
Feldman et al, 0810.5762
FT, Komatsu, 0901.1915

Hamaguchi, Nakamura, Shirai, Yanagida 0811.0737
Hamaguchi, Shirai, Yanagida 0812.2374

Why is lifetime O(10^26) sec?
Why does DM mainly decay into leptons?

Constraints on Dark
Matter Models

No excess in antiprotons

Should mainly annihilate/decay into leptons.

Most of the observed antiprotons
are considered to be secondaries.

-3

10p/p

Quark, W, Z, Higgs
productions tend to lead totoo many antiprotons.

IMAX 1992
BESS 2000
HEAT-pbar 2000
CAPRICE 1998
CAPRICE 1994
BESS-polar 2004
MASS 1991
BESS 1995-97
BESS 1999
PAMELA10-4

1

10
kinetic energy (GeV)

102

Adriani et al, arXiv:0810.4994

How to avoid the anti-proton constraint ?
The dark matter particle decays or annihilates mainly
into leptons (e.g. due to a symmetry).

e.g.) a hidden U(1) gauge boson,
leptophilic dark matter

Maybe the dark matter particle has a lepton number.
e.g.) right-handed sneutrino.

The lepton number as well as a discrete symmetry
responsible for the longevity of dark matter are
explicitly broken altogether.
e.g.) gravitino LSP w/ R-parity violation

Dark matter particle first decays into lighter
particle, which is prevented kinematically from
Arkani-Hamed et al, 0810.0713
decaying into hadrons.
Pospelov et al, 0810.1502

The solar system may be very close to a DM clump.
Hooper et al, 0812.3202

How to avoid the anti-proton constraint ?
myS

Thedarkmatterparticledecaysorannihilates
mainlyyrte
m into leptons (e.g. due to a symmetry).

e.g.) a hidden U(1) gauge boson,
leptophilic dark matter

Maybe the dark matter particle has a lepton number.
e.g.) right-handed sneutrino.

The lepton number as well as a discrete symmetry
responsible for the longevity of dark matter are
explicitly broken altogether.
e.g.) gravitino LSP w/ R-parity violation

Dark matter particle first decays into lighter
particle, which is prevented kinematically from
Arkani-Hamed et al, 0810.0713
decaying into hadrons.
Pospelov et al, 0810.1502

The solar system may be very close to a DM clump.
Hooper et al, 0812.3202

How to avoid the anti-proton constraint ?
myS

Thedarkmatterparticledecaysorannihilates
mainlyyrte
m into leptons (e.g. due to a symmetry).

e.g.) a hidden U(1) gauge boson,
leptophilic dark matterMaybe
DM the dark matter particle has a lepton number.

cine.g.) right-handed sneutrino.
otpeLThe lepton number as well as a discrete symmetry

responsible for the longevity of dark matter are
explicitly broken altogether.

e.g.) gravitino LSP w/ R-parity violation

Dark matter particle first decays into lighter
particle, which is prevented kinematically from
Arkani-Hamed et al, 0810.0713
decaying into hadrons.
Pospelov et al, 0810.1502

The solar system may be very close to a DM clump.
Hooper et al, 0812.3202

How to avoid the anti-proton constraint ?
mySThedarkmatterparticledecaysorannihilates
mainlyyrtem into leptons (e.g. due to a symmetry).

e.g.) a hidden U(1) gauge boson,
leptophilic dark matterMaybe
DM the dark matter particle has a lepton number.

cine.g.) right-handed sneutrino.
otpe
LThe lepton number as well as a discrete symmetryL

responsible for the longevity of dark matter are2
Z
+ explicitly broken altogether.

e.g.) gravitino LSP w/ R-parity violation

Dark matter particle first decays into lighterparticle, which is prevented kinematically fromArkani-Hamed et al, 0810.0713decaying into hadrons.
Pospelov et al, 0810.1502

The solar system may be very close to a DM clump.
Hooper et al, 0812.3202

How to avoid the anti-proton constraint ?
myS

Thedarkmatterparticle
decaysorannihilates
mainlyyrt
em into leptons (e.g. due to a symmetry).

e.g.) a hidden U(1) gauge boson,
leptophilic dark matterMaybe
DM the dark matter particle has a lepton number.

cine.g.) right-handed sneutrino.
otpeL
The lepton number as well as a discrete symmetryLresponsible for the longevity of dark matter are
2Z+ explicitly broken altogether.

.
pupe.g.) gravitino LSP w/ R-parity violationsc
Darkmatter particle first decays into lighter
itaK

m particle, which is prevented kinematically fromein
decaying into hadrons.

Arkani-Hamed et al, 0810.0713
Pospelov et al, 0810.1502

The solar system may be very close to a DM clump.
Hooper et al, 0812.3202

How to avoid the anti-proton constraint ?
mySThedarkmatterparticle
decaysorannihilates
mainlyyrte
m into leptons (e.g. due to a symmetry).

e.g.) a hidden U(1) gauge boson,
leptophilic dark matterMaybe
DM the dark matter particle has a lepton number.

cine.g.) right-handed sneutrino.
otpeL
The lepton number as well as a discrete symmetryL

responsible for the longevity of dark matter are2
Z
+ explicitly broken altogether.

.
pupe.g.) gravitino LSP w/ R-parity violation

scDarkmatter particle first decays into lighter
itam particle, which is prevented kinematically fromeniKArkani-Hamed et al, 0810.0713
decaying
into hadrons.
MDPospelov et al, 0810.1502
ypm
The solar system may be very close to a DM clump.
uClHooper et al, 0812.3202

Gamma-rays
EGRET on CGRO(Compton Gamma Ray Observatory) satellite
detected the gamma rays in the 20MeV-30GeV range.
Diffuse ex.galactic γ -ray BG

excess@~ 10GeV?

(1991-2000)
Strong, Moskalenko and Reimer (`04)

Contributions fromunID point sources?

No excess in neutrinos from Galactic Center
Hisano, Kawasaki, Kohri, Nakayama,0812.0219

Tighter constraints on the annihilating DM scenario.

Synchrotron radiation from Galactic center
Ishiwata, Matsumoto, Moroi, 0811.4492

Big bang nucleosynthesis
Hisano, Kawasaki, Kohri, Nakayama,0810.1892
Hisano, Kawasaki, Kohri, Moroi, Nakayama, 0901.3582

Hidden U(1) Gauge Boson

Hidden-gauge-boson DMChen, Takahashi, Yanagida (2008)
arXiv:0809.0792, 0811.0477

U(1)B-L

U(1)H HiddenSMkinetic mixing

AHx(B-L) ifi-fi

Lifetime OK

1 (H) (H)µν 1 (B) (B)µν λ (H) (B)µν
L(4D) = − Fµν F− Fµν F+ Fµν F4421 21 2µµ+ m AHµ AH + M ABµ AB ,22kinetic mixing

We can make A’s canonical and express them in terms of the2mass-eigenstates:m!
AB ! AB − λM!
A,H2

Coupling to SM fermions:
2mµ!µLint = qi AB ψ̄i γµ ψi ⊃ −λ qi 2 AH ψ̄i γµ ψi ,M
B-L chargeτ ! 1 × 10

26

sec!
"iNi qi2

#−1 $

λ0.01

%−2 &m
1.2 TeV'−5 $M1015 GeV%4,

Lepton dominated decay modes!

Nc (B-L)^2

Quarks

Leptons

1/31

Positron Fraction

Chen, Nojiri, Takahashi, Yanagida (2008)

Electron + positron spectrum:
Chen, Nojiri, Takahashi, Yanagida (2008)

Hidden-gauge-boson DM

Hidden U(1) Gauge Boson
High predictivity on the branching ratios.
Correct lifetime is naturally derived.
Lepton dominated decay modes with
suppressed antiproton flux!
The anti-proton production can be avoided if we
consider the hidden U(1) gaugino!
Shirai, Takahashi, Yanagida (2009)

Conclusion

Conclusions
The origin of PAMELA and ATIC/PPB-BETS signals may beDM decay or annihilation.

Annihilation:!σv" = O(10−23) cm /sec
3Enhancement of 100 - 1000 is needed forthe thermal relic DM.
Or DM may be produced non-thermally.

Decay:

τ = O(10 sec)
26

Conclusions
Cross-check in the gamma-rays and antiprotons will be
important.
One plausible candidate is a hidden U(1) gauge boson/gaugino that mixes with U(1)B-L.

Preliminary Fermi Data

Fermi (formerly GLAST)
Launched on 11th of June, 2008.

20MeV-300GeVFirst-Light sky map with 95 hrs (4 days).

Equivalent to EGRET’s 1st year!!
Many point sources will be identified,
all the data will be released in next August.

Gravitino DM

Gravitino DM with broken R-parity can fit PAMELA
Ishiwata, Matsumoto, Moroi `08[see also Ibarra and Tran`08]

Φ e+ / (Φ e- + Φ e+ )1

[diffusion models]

electron-like Rp

M2

m3/2 = 1.2 TeV

τ3/2 = 10 26sec.

MED
M1

0.1

0.01

110100E [GeV]

1000

Hamaguchi, FT, Yanagida, `09

The gravitino DM can also explain the ATIC data:
Hamaguchi, FT, Yanagida, `09electron-like Rp

m3/2 = 1.2 TeV

τ3/2 = 10 26sec.

100[diffusion models]M23E22

Φ [GeV /m sec str]

1000

MED
M1
1010100

E [GeV]

1000

Gravitational Dark Matter Decay
FT, Eiichiro Komatsu: arXiv:0901.1915

Dark matter particle withm ∼ 1.2 − 1.6 TeV

Mass:Lifetime: τ ∼ 1026 sec
1Γ ∼32π!

vMP"2m ∼ 1.2 TeV

m3σ,
MP2v ∼ 10 GeV
9Then, the abundance is naturally explainedby the coherent oscillations.
Ωφ h = 0.2A
2! g "− 14 !
∗100v
109 GeV"2 ! mσ

1 TeV

" 12.

Three lines meet at one point!!!

Dark Matter Model Selection
Chen, Hamaguchi, Nojiri, FT, Torii
arXiv:0812.4200

Initial source spectrum of electrons is modeldependent:
(i)

dNedE

(ii)

(iii)

E

1000

flat

monochromaticE 3 Φ [GeV2/m2sec str]

E 3 Φ [GeV2/m2sec str]

1000

100(c)(a)(b)

10100(c)
(b)

10100

1000

10(a)
1001000

E [GeV]E [GeV]1000

E 3 Φ [GeV2/m2sec str]

double-peak[diffusion models]
(a)
(b)
(c)

100(c)(b)
1010(a)100E [GeV]

1000

M2MED

M1Decaying DM with
τ = 3.3 × 1026 sec m = 1.4 TeV
τ = 1.1 × 1026 sec m = 1.6 TeV

M1 model

250(i)

(ii)

200

3E

22

Φ [GeV /m sec str]

300

(iii)

150

(decay)

(i)
(ii)
(iii)

100
50

0

100

mono

(annihilation)
mono

flat
doubleflat
double

200

300

400

500

E [GeV]

600

700

800

Smearing EffectFermi: 10% energy resolution
CALET: (7/sqrt[E/10GeV] + 1)%

CALET 5yr data may be able to tell thedifference between double-peak and flat ones.
Solid:
double-peakDotted:Flat w/ 800GeV
Dashed:Flat w/ 820GeV