ダークマターとCTA

Physics Department, Tohoku University Physics Department, Tohoku University

（郡 和範）Kazunori KohriKazunori Kohri

http://map.gsfc.nasa.gov/media/060916

Dark Matter?

2CDM 0.1Ω ∼h

0

ii

c

ρρ

Ω ≡

What is Dark Matter?• It is massive (ρ∝a-3)

• It is stable (τ>> 10 18 sec)

• It does not scatter off photons so much( Is it a bound-state?)

• It is neutral (from experiments of sea water m<106 GeV)

• The velocity dispersion is small [cold dark matter (CDM)]

Candidate of particle (cold) dark matter• Stable or long-lived new particle

• Oscillating scalar field

• Neutralino• Gravitino• Right-handed sneutrino• Axino• …

• Axion• Moduli• …

Another candidates

• Primordial black hole• Brown dwarf• WIMPZILLA• Integral constant in Horava-Lifshitz gravity• Quark nugget (strange-quark matter)• Solutions in (relativistic-) Modified

Newtonian Dynamics (MOND)• …

Rotation curve

二間瀬敏史著 「なっとくする宇宙論」

( )M r r∝ Begeman, Broils,Sandars etal (91)

Dark Halo

gas

Stars (visible component)

Gravitational lens in colliding cluster of galaxies

• Red: Baryon observed by X-ray produced by bremsof thermal electron

• Blue: DM observed by gravitational lens

(2007)

Time-evolution of fluctuation III

Ma and Bertschinger (95)

See also 松原隆彦 「シリーズ 現代の天文学3 宇宙論 ＩＩ 宇宙の進化」

-6 -5 -4 -3 -2 -1

Log a

(II) Horizon reentry before matter-radiation equality epoch

∝a

∝a２

aEQ

Cluster baryon fraction

• Cluster can have a representative distribution in the Universe of both baryon and DM

• Ωbh2 is independently known, fgas was observed by X-ray from Oxygen

Ωm~ 0.2

Combined Figure

Riess et al (98), Lahav-Liddle PDG (09)

Fermion Boson

Introduction toIntroduction to SUSYSUSYSupersymmetry (SUSY)

Solving “Hierarchy Problem”

Realizing “Coupling constant unification in GUT”

quark squark

lepton slepton

gravitino graviton

photino photonneutralino

Depending on SUGRA models

12-13 orders of magnitude !!!

Hierarchy ProblemsHierarchy Problems

≈ 14 1510 - 10 GeVXM

≈ 2 310 -10 GeVWM

GUT-scale

Weak-scale

Higgs mass 22 20 2

2 ( )Wd Vm O Md

ϕϕ υλ

ϕ= ≈ ≈

( )ϕ λ ϕ ϕ υ= −2† 2 /2V

where Higgs’s potential

ϕ

Vϕ

~υc.f) Masses of fermions and vector bosons

ψ ψ ϕ ϕ~ , ~Zm h m g

Radiative correction to Higgs mass Radiative correction to Higgs mass in Quantum Field Theoryin Quantum Field Theory

ϕδ λΛ + Λ2 2 2 2~m gλϕ ϕ

ϕ

ϕ ϕg g

W

Λ 15Cut off scale ~ ~ 10 GeVXM

+

( )ϕδ22 15~ 10 GeV ?m

Quadratic divergence

How can we resolve the problem?How can we resolve the problem?Weak scale in the tree level, ( )

( )21

220

2 5

2~ 10 GeV

~ 10 GeV

m

mϕ

ϕ

δ

( )ϕϕ ϕ δ+

222 2 15 0 ~~ 10 GeV ?m mm

To retain the hierarchy, we require an accidental cancellation,

( )ϕ ϕ ϕ ϕδ δ δ+ + + +22 2 2 2 2

0 1 2 3 ... ~ 10 GeV ?m m m m

⎡ ⎤⎣ ⎦215(10 GeV)O

Fine tuning!Fine tuning!

In total,

$ 10,110,087,734,958.95-) $ 10,110,087,734,957.70

$ 1.25

GDP in USA (2002)?

Solution in SUSYSolution in SUSYIn exact SUSY, the quadratic divergence is canceled by both boson and fermion loops.

2thϕ ϕ

t

+ 0=ϕ ϕ

tth th

Exact SUSY2 2

2

1(4 ) thπ

Λ2 22

1 (4 ) thπ

− Λ

Even if SUSY,

ϕδπ

⎛ ⎞Λ⎜ ⎟⎜ ⎟⎝ ⎠

∼ 2

2

22 2

2

1ln

(4 )t

t

th m

mm

We don’t need a fine tuning when

∼ ∼ ∼2 2 2... ( )t Wb

mm OM

SUSY GUTSUSY GUT

The coupling constants are unified at

≈ 1610 GeVXM

A lot of new particles ,which do not obey the asymptotic free, appear at

μ ≥ 210 GeVMartin, ”A Supersymmetry Primer”

Lightest SUSY particle (LSP)• R-parity conservation

i)Decay

ii) Pair annihilation/production

τ χ τ→ +

χ χ+ ↔ +f f

(-1) (-1)×

(-1)× (-1)

(+1)

(+1) ×(+1)

Thermal freezeoutBoltzmann equation

frezeout

3χ σ∼ Hn

v

( )2

20.10.1

TeVχ

σ⎛ ⎞⎜ ⎟Ω ⎜ ⎟⎜ ⎟⎝ ⎠

∼v

h

Freezeout / 30χ∼T m

Ωχ does not depend on mχ

Kolb & Turner

Predicting TeV Physics!!! 26 33 10 /v cm sσ −= ×

Positron Excess (PAMELA satellite reported)

Adriani et al, arXiv:0810.4995v1 [astro-ph]

/ ( ~0.6 proton diffusion)e e E δ δ+ − −∝

Electron and positron flux by ATIC2

Chang et al (08)

Electron and positron flux by Fermi

Abdo et al, Fermi LAT Collaboration, arXiv:0905.0025, PRL102 (09) 181101

Hisano, Kawasaki,

Kohri, Moroi, Nakayama (09)

Positron excess

in DM annihilation

Diffusion model

Fitted to B/C ratio

24 23 310 10 /v cm sσ − −−∼

Hisano, Kawasaki,

Kohri, Moroi, Nakayama (09)

Electron/positron cutoff

in DM annihilation

23 310 /v cm sσ −∼

Kawasaki, Kohri, Nakayama (09)Gamma-ray signal from GC by DM annihilation

Kawasaki, Kohri, Nakayama (09)

Extragalactic diffuse Gamma-ray by DM annihilation

Fitting by Papucci and StrumiaPapucci, Strumia, arXiv:0912.0742 [hep-ph]

See also Chen, Mandal and F. Takahashi, arXiv:0910.2639 [hep-ph]

CTA?

Courtesy of Kazunori Nakayama

Result of Papucci and StrumiaPapucci, Strumia, arXiv:0912.0742v1 [hep-ph]

Extragalactic diffuse-gamma

CTA?

Direct detection by CDMSII

2recoil

1~ ~ (10)keV2μE v O

-3~ 220km/s (v/c~10 )v

Ge DM

Ge DM

~ m mm m

μ+

Ge 72.6 um =

Ge DMm m

arXiv:0912.3592v1 [astro-ph.CO]

M < O(100) GeV? (Farina et al)

Background

0.8 ±0.1(stat) ±0.2(syst)

arXiv:0912.5038v1 [hep-ph]Marco Farina, Duccio Pappadopulo, Alessandro Strumia

ConclusionConclusion• Fermi may not exclude the possible scenarios

for the positron/electron excess by the DM annihilation/decay because of the upper limit on the sensitivity (<300 GeV)

• CTA will be able to verify those scenarios

• CTA may have a sufficient sensitivity to detect gamma-rays associated with DM annihilation even with its canonical annihilation cross section (~3×10-26 cm3/s)