暗黒物質対消滅起源のガンマ線暗黒物質対消滅起源のガンマ線

研究会「研究会「 CANGAROOCANGAROO 望遠鏡によるガンマ線天文学の新展開」望遠鏡によるガンマ線天文学の新展開」日時：　２００３年１２月１１日（木）日時：　２００３年１２月１１日（木） -- １２日（金）１２日（金）

場所：　京都大学 基礎物理学研究所 湯川記念館場所：　京都大学 基礎物理学研究所 湯川記念館 3F 3F 大講演大講演室室

久野純治　 (東京大学宇宙線研究所）

1, Introduction1, Introduction

Fit to the WMAP , CBI, ACBAR,2dFGRS and Lyman α forest data

2dFGRS 　 v.s. N-body simulation for Large-scale structure formation

What is this dark matter?

Evidence of cold dark matterEvidence of cold dark matter

Candidate of dark matterCandidate of dark matter

MACHO (almost excluded)MACHO (almost excluded) MicrolensingMicrolensing Wide binaries Wide binaries

Neutrino (Not cold)Neutrino (Not cold) It might be hot dark matter, thus It might be hot dark matter, thus

Unknown stable particle Unknown stable particle Relics in the early hot universe.Relics in the early hot universe. WIMP (Weakly interacting massive particleWIMP (Weakly interacting massive particle) (Cold)) (Cold) SUSY particleSUSY particle, Kaluza-Klein particle, Wimpzilla,,,, Kaluza-Klein particle, Wimpzilla,,, Axion (Cold)Axion (Cold)

7.510 30M M M 45M M

0.01 ( 1 )m eV

(Chaname et al)

SUSY dark matterSUSY dark matter

Solves hierarchy problemSolves hierarchy problem

SUSY GUTsSUSY GUTs

Light Higgs bosonLight Higgs boson

Lightest SUSY particle(LSP) is Lightest SUSY particle(LSP) is

stable due to R parity. stable due to R parity.

SM particles; even, SUSY particles; oddSM particles; even, SUSY particles; odd

　→ 　→ Dark MatterDark Matter

Nature of LSPNature of LSP

It depends on the SUSY breaking mechanismIt depends on the SUSY breaking mechanism

Neutralino ;Neutralino ;

Bino -like or Higgsino -like in supergravityBino -like or Higgsino -like in supergravity

Wino -like in the anomaly mediationWino -like in the anomaly mediation

Gravitino in the gauge mediationGravitino in the gauge mediation

Direct search for DMDirect search for DM 　ｂｙ 　ｂｙ the nucleus elastic scatterithe nucleus elastic scatteringng

Dirac neutrino (sneutrino) mass > 100TEVDirac neutrino (sneutrino) mass > 100TEV

Dark matter should be Majorana fermion or real scalarDark matter should be Majorana fermion or real scalar

　　　　 if it has weak charge.if it has weak charge.

0 0 0 0 01 1 2 3 3 1 4 2a B a W a H a H 0

1( )0( )B 0( )H

03( )W

0( )G

DM genesisDM genesis

Thermal abundance Thermal abundance

is blocked when is blocked when

Smaller may mean Smaller may mean

larger annihilation rate.larger annihilation rate.

Notice co-annihilation may Notice co-annihilation may

enhances cross section whenenhances cross section when

SUSY particles masses are degenerate.SUSY particles masses are degenerate.

01

2(5 6) (1/100 )

10 eff

annihiration

GeV

v

( 0.27)DM

0 01 1 SM particles

01

1/ 20 .T m

0 01 1 1, ,SM particles SM particles

(Nath et al)

Non-thermal production Non-thermal production

DM is produced after by non-thermal DM is produced after by non-thermal process. process.

(for example, ) (for example, )

In this case, the larger annihilation rate, such as in In this case, the larger annihilation rate, such as in

Higgsino-like or Wino-like case, is favored.Higgsino-like or Wino-like case, is favored.

01

1/ 20T m

01, ,G Qball

01

01

2(5 6) 1/ 20 (1/100 )

10/ eff

annihiration

GeV

T m v

Detection of DMDetection of DMDirect detection by elastic scattering with nucleus.Direct detection by elastic scattering with nucleus.

　　　　 DAMA, EDELWEISS, CDMS, Zeplin, …… DAMA, EDELWEISS, CDMS, Zeplin, ……

Indirect detection of neutrinos, antiproton, positron, and Indirect detection of neutrinos, antiproton, positron, and gamma raygamma ray from DM annihilation in our Galaxy, Sun, or from DM annihilation in our Galaxy, Sun, or Eearh.Eearh.

Collider experiment Collider experiment

LHC starts on 07’.LHC starts on 07’.

It determine mass and properties of the DM candidate.It determine mass and properties of the DM candidate.

0 01 1N N

0 01 1 , , ,p e

2, Dark matter distribution2, Dark matter distribution

N-body simulation provides N-body simulation provides uniuniversal cuspy profileversal cuspy profile for the hal for the halo DM density distributon (Navao DM density distributon (Navarro, Frenk & White, 96,97).rro, Frenk & White, 96,97).

02

0 0

099 1.51.5

0 0

( )( / )(1 / )

( )( / ) (1 / )

NFW

M

rr r r r

rr r r r

Navarro, Frenk &White

Moore

High resolution N body simulationHigh resolution N body simulationLarge N and small time stepsize are required.Large N and small time stepsize are required.

( (10) )N O M

Time evolution

Recent simulation observeddeviation from the universal profile for 0.01 .Vr r

(Figures;Fukushige and Makino)

Cusp/Core problemCusp/Core problem

Rotation curve measure ment of Low Surface-brightRotation curve measure ment of Low Surface-brightness Galaxies by HI and Halpha.ness Galaxies by HI and Halpha.

Data prefer soft cores .Data prefer soft cores .

Early suspicion on observation;Early suspicion on observation; beaming, pointing error,beaming, pointing error, small sample, inconsistencysmall sample, inconsistency among observations, etc.among observations, etc.

de Blok(2003): These problemsde Blok(2003): These problemsno more exit.no more exit.

Measurement of gravitational Measurement of gravitational lense constrains DM profile flense constrains DM profile for clusters.or clusters.

Sand et al showSand et al show

Objection :Ellipticity (Dalal et Objection :Ellipticity (Dalal et al)al)

A little good news.A little good news.

for large radius is favorefor large radius is favored.d.

(CL0024+11654, Kneib et al)(CL0024+11654, Kneib et al)

31/ r

0.54

Our galaxyOur galaxy

Our galaxy is High surface-brightness galaxy.Our galaxy is High surface-brightness galaxy.

(Baryon rich, Bar, BH )(Baryon rich, Bar, BH )

It is difficult to say something, especially DM It is difficult to say something, especially DM profile around the galactic center.profile around the galactic center.

http://www.astronomynotes.com/ismnotes/rotcurv2-big.gif

3, Gamma ray from DM annihilation3, Gamma ray from DM annihilationin Galactic centerin Galactic center

Gamma ray from DM annihilationGamma ray from DM annihilation

line spectrum:line spectrum:

continuum spectrum:continuum spectrum:

Merit and DemeritMerit and Demerit

Merit: Characteristic spectrum, e.g. line.Merit: Characteristic spectrum, e.g. line.

Sensitive to heavier DMSensitive to heavier DM

Demerit: Cross section depends on DM propartieDemerit: Cross section depends on DM proparties.s.

Sensitive to DM halo profile.Sensitive to DM halo profile.

0 0 01 1 , Z

0 0 0 0 01 1 , ,W W Z Z

Gamma ray fluxGamma ray flux

01

12 -2 -1 -1

2

' '27 3 -1

'

2

-3lineof sight

( )9.3 10 cm sec GeV

100GeV

10 cm sec

where

1

8.5kpc 0.3GeVcm

VV VV

VV

DM

d EJ

dE

vdN

m dE

J d dl

Galactic Halo profileGalactic Halo profile

Dependence on DM profile is huge.Dependence on DM profile is huge.2

-3lineof sight

1

8.5kpc 0.3GeVcmDMJ d dl

5099 1.51.5

0 0

302

0 0

10modifed 2isothermal

0

-3 30 0

( ) 10( / ) (1 / )

( ) 10( / )(1 / )

( ) 3 10(1 / )

for 8.5kpc, ( ) 0.3GeVcm and 10 .

M

NFW

DM

r Jr r r r

r Jr r r r

r Jr r

R R

In the following, I take the moderate value, that is 310 .J

DM annihilation cross sectionDM annihilation cross section

Annihilation cross section to fermions is suppressed bAnnihilation cross section to fermions is suppressed by the fermion mass due to the S wave annihilation.y the fermion mass due to the S wave annihilation.

Sizable cross section to continum gammais expected Sizable cross section to continum gammais expected whenwhen

Cross section depends on propaties of the DM.Cross section depends on propaties of the DM.

Case 1:Bino-like DM. Case 1:Bino-like DM.

Interaction is very weak.Interaction is very weak.

MSUGRA + thermal production favor this.MSUGRA + thermal production favor this.

Case 2: Higgsino or Wino DM.Case 2: Higgsino or Wino DM.

These have SU(2) weak charge.These have SU(2) weak charge.

01

.Wm m

Bino-like DMBino-like DM

Line spectrum.Line spectrum.

Sensitive to slepton mass.Sensitive to slepton mass.

Continuum spectrumContinuum spectrum

MSUGRA simulation byMSUGRA simulation by

Feng et al.Feng et al.

01

22

2 4W l

mv

c m

4

12 -2 -13 3

100GeV2.0 10 cm sec

10 10l

J

m

01

61,97,120, 202GeV.m

Higgsino or Wino DMHiggsino or Wino DM

They have SU(2) weak charge and acompany with They have SU(2) weak charge and acompany with SU(2) partner, those are chargino, When they arSU(2) partner, those are chargino, When they are heavier than W boson mass, the masses are degee heavier than W boson mass, the masses are degenerate.nerate.

Annihiration cross section to 2 gamma’s is independAnnihiration cross section to 2 gamma’s is independent of the DM mass at the leading order.ent of the DM mass at the leading order.

This means that line gamma search is sensitive toThis means that line gamma search is sensitive to

heavier DM.heavier DM.

However, this behavior is strange since However, this behavior is strange since

.

2

2 2

1 14 For Wino(Higgsino)

4 W W

vs m

01

2

4.v

vm

Non-relativistic effectsNon-relativistic effectsDM is highly non-relativistic . Thus, the cross DM is highly non-relativistic . Thus, the cross section is sensitive to existence of bound state under section is sensitive to existence of bound state under Yukawa potential induced by W exchange.Yukawa potential induced by W exchange.

3( / 10 )v c

3 1 0 0( sec ) 2v cm for

Wino-like

Higgsino-like Leading order cal.

0.1GeVm

1GeVm

3/ 10v c

Bound state

2 / 2 0E mv

W-exchangedYukawa potential

Zero energy resonance enhances the cross section.

Line spectrum ( ).Line spectrum ( ).

310

Wino-like Higgsino-like

-2 -1 3(cm sec ) 10Flux

0.1m GeV

0.1m GeV

1m GeV 1m GeV

Continuum spectrum ( )Continuum spectrum ( )

Wino-like Higgsino-like

Pho

ton

ener

gy (

GeV

)

2 1 1( sec )Flux cm GeV 2 1 1( sec )Flux cm GeV

There are already some regions constrained by the EGRET.

1710

17101510

15101310

13101110

1110

910

1910

30.1GeV , 10m

The shaded regions correspond to S> BG.5 2.7

. . / 9.1 10 ( /1GeV) (EGLET)B Gd dE E

EGLETEGLETGamma ray spectrum from Galactic center observed by EGLET is not well fit to the standard explanation of diffused gamma,

It might come from DM annihilation.

0, 2 (index=2.72)p He X

(Cesarini et al)

4, Summary4, Summary

After WMAP measurement, DM search is very important subjecAfter WMAP measurement, DM search is very important subject. Gamma from DM annihilation is sensitive to relatively heavier t. Gamma from DM annihilation is sensitive to relatively heavier DM, and it has different dependence from other DM searches.DM, and it has different dependence from other DM searches.

Will gamma from DM annihilation at Galactic center be observeWill gamma from DM annihilation at Galactic center be observed or not ? Or, can we discriminate particle physics models or asd or not ? Or, can we discriminate particle physics models or astronomical models? At present, it is hard to answer them, becautronomical models? At present, it is hard to answer them, because gamma ray signal depend on detail of both models.se gamma ray signal depend on detail of both models.

If DM candidate is discovered at new collider (LHC?) or DM-like If DM candidate is discovered at new collider (LHC?) or DM-like gamma ray is observed, DM astronomy will be started.gamma ray is observed, DM astronomy will be started.