SMILE2+とSubGeV & MeV WIMPレビュー

5th/July/2019@Waseda DM Meeting
T. Tanimori on behalf of SMILE-Project,
Cosmic-ray group, Physics Division, Kyoto University, Japan1

2Contents➢ Indirect Search in GeV gmainly Fermi results➢ MeV Sub-MeV DMとは？
➢ MeV g region の特徴➢ SMILE 2+ 紹介➢ SMILE2+ 実験の解析
➢ まとめ

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C. Boehm @Wein 20166

Astronomical sources7◼ 1. gammas from pion decays( ex. Stellar bulge, molecular clounds etc)
◼ millisecond pulsars in bulges
F. Calore@Fermi.sym.2018

Normalized spectra of 39 MSPs.

Y.Xing and Z.Wang 2016

GeVからMeVへ

8◼ GeV

Galactic Center Region
astnophysical sources 多数、
Steller-bulge, Sgr A*,
Molecular Clouds, Millisecond
Pulsars,,,,EGRETFermi◼ MeV region <30MeV

gammas mainly fromInverse Compton and Bremss.
from electron, positron
B. LACKI , S.HORIUCHI J F. BEACOM 2014 arXiv:1206.0772v3

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MeV ~Sub-GeV DM
Mass limit DM >~3MeV from CMB obs.
XX → gg, π0π0->ggg, γϕ-> ggg, ϕϕ → gggg
XX →e+e-, π+π-, μ+μ-, ϕϕ-> e+e-e+-eSignal gammas from DM ,direct g& radiative g from decayed e＋ GEV DM からのe+ e-からのsecondary gammas
GeV より拡散が小さい！

それ以外●Axion Like Particles (ALPs)
10MeV gammas from SN （カットする）●PBHthermail MeV gamma

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Electron Tracking Compton Camera (SMILE-II)

electronMicro Pixel
Chamber

30cm-cubic Gas Time Projection Chamber+ Scintillator Array for scattered g--- tracking of recoil electron --Measuring all parameters of Compton process
1.well-defined 2D-PSF similar to Xray & GeV
2. dE/dx + kinematical test using a
3. large Field of View (>4str)
 is a Half Power Radius (HPR)

PSF(1o)PSF(10o)

Measured data(ARM 5o)

Sub-MeV gamma-ray Imaging
Loaded-on-balloon Experiment (SMILE-Project)
From basic research of nuclear g imaging
spectroscopy to Satellite observation withsub-m Crab sensitivity (4orders improvements)
200㎝2

Satellite-ETCC

SMILE-I
SpectrumTwo order
BG rejection
By dE/dx cut

2006 SMILE-I
10cm cubic ETCC

Effective Area
1㎝2

SMILE-Ⅲ
SMILE-II+
SMILE-II+ 30cmETCC
2016~2020?

SMILE-II

SMILE-II 2010~16

0.01㎝230cm
ETCC

SMILE-I~1 m～60㎝

SMILE-2+

Aim : certificate imaging spectroscopy of ETCC using celestial objects
Targets : e± annihilation line from the galactic center region / Crab nebula
SMILE-2+ balloon, Flight Model, ETCC

gandoraFlight duration ~29 hourslevel flight~26 hours©googleSMILE-II+ Exp. 2018 4/7~8 in Alice Spring
Detection Area

escaped e- event
gamma-rayfully contained e- event
gamma-raygas detectore- track

e- track

αhit pixelhit pixel

pixel scintillator arrays

pixel scintillator arrays

Ratio of obtained events 3 : 2

Event rate after kinematicalcut [events/sec]

Zenith [degree]Time Variation of detection rate of gamma-ray events• Fly horizontally 26 times

90
60

GCSunCrabGC

30
0
Used only in this time
window108642Preliminary

0
4/7
03:00

Level flight
4/7
09:00

4/7
15:00

4/8
4/8
4/7
21:00 03:00 09:00• Height ~39 km• Galaxy center field ~8 time
Event selection Preliminary
Single hit in PSA
Fiducial volume
de/dx cutKinematical test
Zenith<60°

Enhancement looks consistent
with the observation ratio of thecosmic diffusion and galactic
diffusion of about 3:1• After 7 o’clock 4/8
heavy nose in TPC
Now we used data before 7

Cosmic background MeV gammas

Zenith angle more z>60 degrees => more 105 gamma rays
Backgrounds of air diffuse & equipment gamma ray are expectedless than a few 10% in total.

DM探査➢ 0.5-5MeVのスペクトル変化➢ 全天の2/3をカバー、今後、超銀河団、銀河団、矮小銀河等との相関を調べる。

Excess gamma rays from Galactic Center
Analysis of the event rate in the ON and OFF
Select the high Declination center of the field 4/7 9:00-13:00 (ACST) Galactic
coordinatesof view to OFF
zenith angle (only available for 30 °)(Currently, because there is indeterminable inthe azimuth direction, only the fieldtime
information is used)

OFFON A
4/7 18:00-20:30 (ACST)

events/sec/keV

ON B

ON C

4/7 22:00-24:30 (ACST)

4/8 4:00-6:30 (ACST)

events/sec/keV

spectrum

spectrum

10-3
10-4
10-5
10-6100

ON-A
OFF
Residual

10-3

events/sec/keV

ON-B
OFF
Residual

spectrum

10-3

10-4

10-410-510-510-6300 50 1000 keV 100
030050 1000
010-6keV 100ON-COFF
Residual30050 1000
0An excess of ~ 511 keV & diffuse components in G.C. is observed.

keV

Excess gammas from Galactic Center
Analysis of the event rate in the ON
and OFF time zones
OFF of the View Center is far from thegalactic plane
Select two time zones
Ground coordinate zenith angle (onlyavailable for 30 °)OFFTime zoneA

4/8 4:00-6:30 (ACST)

ONTime zone Galactic coordinates
OFFTime zoneB

4/7 9:00-13:00(ACST)

4/7 21:00-23:00(ACST)

events/sec/keV

events/sec/keV
Energy Spectrum

10-3

Energy Spectrum ON
OFF-A
residual

10-4

10-5
10-6
100

10-3ONOFF-B
residual

10-4

4.90 σ10-5

Excess : 11.5 σ
300 50

1000

3000
keV

10-6100

5.36 σExcess: 10.3 σ
300 501000

keV3000

Comparison of significance with other observations
COSI 2016

10−3Balloon
46 Days~34 km

10−4Siegert et al. 2016
500 510 520 keV

10−510−6

INTEGRAL/SPI

BG 1/8V

events/sec/ke

SMILE-2+Chiu et al. 2017100

500 1000keV

SMILE-2+ 511 keV bin~5 σ511 keV bin over duffuse ~2 σSame time with COSI : ~5 σ ×・511 keV line 58 σ・3-gammas 29 σ・combined

65 σ

6.1 ×105 sec= 20~48 σ
6.4 ×103 sec

INTEGRAL/SPI same time: ~5σ ×

1.6 × 109 cm2 sec /75cm²= 140~295
6.4 ×103 sec

Eff. Area

ΔE/E

Normalized Sensitivity to SPI

75cm2<1%１COSI~10cm2<1%

5 x Conventional CC with Veto

SM2+

1cm2

13%

100ー200 xInstum.
SPIσ

Coded Mask with Veto
ETCC with no-vetogalactic diffuse gamma rays
events/sec/keVEnergy Spectrum
差分10-3COMPTEL

10-4

INTEGRL

10-5
10-6100300 500 1000

3000keVAll excess : 10～11σStrong+(2011)clarify the radiation mechanism of thediffuse Mev gamma rays

Expected Sensitivity based on well-defined PSF
SMILE2 + = > Crab, Galaxy 511keV Galaxy diffuse & cosmic background
MeV gamma Detected by the sensitivity as planned = > The world's first inMEV!!
PSF by HPR
we have certificated a high realiability of ETCC
ETCC-Satellite 50cm-cubic ETCC (CF4 3atm)with >5RL Scinti. x 4 modules
Effective Area ~200cm2@1MeV and PSF:HPR-2o

For Continuum g (106 sec)

ラインガンマ線はさらに1桁近い感度向上。

６０Ｍｐｃ SN~20SNe/year

New MeV gamma Astronomy
beynond 1mCrab

Summary◆ SM2＋ in the ETCC technology demonstrated in theCompton area (50kev-30MeV) imaging spectroscopic
technique for the first time, as well as x-ray, GEV,◆ GeV 領域 Astrophysical sourcesが多く、DMとの判断が困難。
◆ GeV、sub-GeV. MeV のDM信号は30MeV以下の電子の寄与のみの領域が最も判別が確かであり、今後重要となる。
◆ GeV-MeV 全天探査が可能、銀河と他の銀河、銀河団などが同時に測定できる。
◆ SM2+のデータ DM関係で、Galactic Diffuse gamma（スペクトル、分布）, Cosmic Diffuse gamma（スペクトル、分布）,PBH in Solar system の論文は出す◆ Balloon SMILE-3 project with NASA long duration
balloon ＝＞ 5times better sensitivity than COMPTEL◆ 2020年代 sau-MeV, MEV はSMILEの独断場の可能性大！

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Primordial Black Holes in Solar System M M3
~~ 1010 yr  15  10 g 315
 10 g 
dE
10g
20-1

  ~ 100 MeV ~ 10 erg s dt
 M 
 M 
215

Primordial B.H. still surviving
would emit ~20MeV thermal M~ 1015 g , ~ 1020 erg/s
Density ~104 pc-3 (flat 分布で）104 pc-3 -> ~10 BH <Oort cloud (104AU)
Condensation Factor in Galactic halos x ~106＝＞ 100AU 球に~10BHs

Satellite-ETCC g線１０個 (1MeV)s-1 @1AU for 1020erg/s
ＢＨが106ｓの間同じ天球位置として、検出限界100g@106s
この場合、300ＡＵのＢＨまで観測可能 数10個のＢＨが見える。
さらに太陽系の増幅効果、ディスク（黄道面）分布、太陽近傍集中1桁以上の増加、さらにコメット軌道（数日、明るい）、

[counts/sec/keV]

Crab (0.2-0.8MeV)

Trajectory of FoV of SM2;+ON-region
OFF-region
ON – OFF
Expected flux

10-4

Crab-

10-5
Crab-OFF

10-6102103 102

Sensitivity

Crab-ON

Here pointing is done only for Zenith

Enhancement of gamma-rays
Obs, time ~104sec, 3s=>Obs. time~106sec, ~0.1 Crab(3sdetection)

This results

Designedsensitivity inSM2+Achieved for the first time thatobserved sensitivity isconsistent with original design in
MeV gamma-ray telescopes

Comment
In COSI, 511keV signal from G.C. is obtained by
the subtraction of ~70times large 511kev
background peak.
In SMILE2+., as shown in light curve of gammas,
gamma rate of G.C. region was stronger than thebackground region ( side region of Galactic plane),28

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