Search for Dark Matter with CTA

Kaz Kohri
郡 和範
Theory Center, KEK and SOKENDAI, Tsukuba

Planck Satellite
Invisible matter

Visible matter

Not even matter

Candidate of Dark Ma/er
My favorite DM (推しダークマター)• WIMP• Axion• Primordial Black Hole• ...
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Kaz Kohri (KEK)WIMP
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Kaz Kohri (KEK)Weakly-Interac@ng Massive Par@cle(WIMP)• σann is close to that of Weak Interac@on [~(TeV)-2 ]• ΩWIMP coincides ΩDM,obs (if <σv>~3 ×10-26 cm3/s )• The Lightest SUSY Par@cle (LSP ) can be WIMP
χ = c 1B! + c 2W! + c 3H! 1 + c 4H! 2⇔ photon, Z-boson, Higgs

Bino, Wino, Higgsino 1, Higgsino 2
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Kaz Kohri (KEK)1) Produc@on of WIMP in the early
Universe• Le[ from the cosmic expansion (freeze-out)

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Kazunori Kohri (KEK/Sokendai)

Thermal freeze out of WIMP

∝a3

ρDMs=m∝a3

ρ χ / s ∝ Exp[-m/T]nχsρ χ / s → const.

⎛ σv ⎞⎛ m ⎞⎟xF ≡~ 24 + ln ⎜⎟ + ln ⎜−2⎜ TeV ⎟⎜⎝ TeV ⎟⎠TF⎝⎠m

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Kaz Kohri (KEK)

Only weakly-dependent onmass and cross section

Canonical Cross section σ v canonicalBoltzmann equation

Freezeout ( expansion rateρχs=mFnχs∼mF~3Hσv s⎛⎞ρχσv⎜⎟Ωχ ≡∼ 0.25 ⎜2⎟
ρ total
0.1⎜⎟⎝
TeV ⎠(Ω does not depend on mχ

σv

canonical
19/03/14= 3 × 10−26cm 3sec~

0.34(TeV)2)> annihilation rate )−1F1m~×σ v mPlanck TF⎛ σv ⎞⎛ m ⎞⎟xF ≡~ 24 + ln ⎜⎟ + ln ⎜−2 ⎟⎜⎜⎟TFTeV⎝ TeV ⎠⎝⎠mSuggesting TeV –scale Physics, e.g., SUSYm SUSY particles ~ Δm Higgs ~ O (1)TeV

Higgs mass and SUSY breaking

M: uni. gaugino mass
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We need a higher SUSY breaking
with >>10 TeVKaz Kohri (KEK)
Ibanez et al, arXiv:1301.5167

SUSY breaking scales• Gravitino mass represents the scale of SUSYbreaking
W! tends to be the LSP⎧ >> O (1)TeVanomaly mediation⎪Fm3/2 ∼∼ ⎨ >∼ O (102 )GeV-O (1)TeV gravity med.
Mp ⎪2
<O(10)GeV-O(1)TeVgauge med.
⎩gravitino tends to be the LSP
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Kaz Kohri (KEK)Mass matrix of neutralinos• Mass matrix• Mass parameters, e.g., in anomaly-mediated
SUSY breaking

Giudice, Luty, Murayama, Rattazzi, 1998
Randall and Sundram, 1998

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Kaz Kohri (KEK)M  : M2  : M3 = 3.3 : 1 :  − 10
 1Should we s@ck to canonical σ?
σ < σ canonical• Such a larger relic density can be diluted
by entropy produc@on e.g, by massivedecaying par@cles (moduli, gravi@no, ...)

σ > σ canonical• Such a smaller relic density can be
replaced by non-thermally-produced DMe.g, by massive-decaying par@cles(moduli, gravi@no, ...)
We may allow even a decaying DM with lifetime of > 1026 sec throughanother interactions or a parity violation (e.g., R-parity violation in SUSY)
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Kaz Kohri (KEK)Products from DM annihila@on/decay• DM → WW (Wino neutralino LSP or ...)⎧→ q + q → p + p + n + n + π + + π − + π 0 + ...
⎪→ p + p + e − + ν + γ + ...
⎨⎪→ ℓ ± + ν → e − + ν + γ + ...
⎩• DM → b bbar (neutralino LSP, or ...)
→ p + p + n + n + π + + π − + π 0 + ...
→ p + p + e − + ν + γ + ...

• DM → leptons (slepton LSP, νR, , scalar νR, , or ...)
19/03/14→ ℓ ± + ν → e − +Kaz
ν Kohri+ γ (KEK)+ ...

Future TeV-gamma observa@on
Cherenkov Telescope Array (CTA)
One order of magnitude be/er sensi@vity at TeV

19/03/14Kaz Kohri (KEK)Fermi bounds on annihila@on into WW
M. L. Ahnen et al., MAGIC and Fermi-LAT Collaborations, arXiv:1601.06590[astro-ph.HE]

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Kaz Kohri (KEK)BBN and CMB constraints on winoannihila@ons

Hisano, Kawasaki, Kohri, Moroi, Nakayama, 2008; 2009
Kawasaki, Kohri, Moroi, Takaesu, 2015

CMB
canonical

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Kaz Kohri(KEK)
See also, Hisano,S.Matsumoto,
M.M.Nojiri, O.Saito, 2004

Line searchDMe!ffDMe

Br(DM+DM → γ +γ ) ≡σ (DM+DM → γ +γ )σ total~ α 2 ~ 10−4

Note that Br to line gammas can be 0.01 – 0.1 for wino LSP
because wino couples to gauge boson
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Kaz Kohri (KEK)HESS constraints on line-emission by annihila@ng
DM for both general and Wino cases
H.E.S.S. Collaboration: H. Abdalla, F. Aharonian et al, arXiv:1810.00995 [astroph.HE]

canonical

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canonical

Kaz Kohri (KEK)Sensi@vity of CTA
General cases

Line gamma casecanonical

CTA collaboration, John Carr et al,arXiv:1508.06128 [astro-ph.HE]
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Lefranc et al, arXiv:1608.00786 [astro-ph.HE]
Kaz Kohri (KEK)Point source or Diﬀusive source?
• However, Fermi observed each dwarf
Spheroidal galaxy to be a point source inO(0.1°) x O(0.1°)• CTA can resolve the spa@al structure muchbe/er in future, e.g., in 0.03° x 0.03°• The limit should have been stronger bymeasuring it to be a point source
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Kaz Kohri (KEK)Nagisa Hiroshima’s talk slide

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Kaz Kohri (KEK)Nagisa Hiroshima’s talk slide

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Kaz Kohri (KEK)Summary• CTA improves the sensi@vity at 100 GeV – 100
TeV approximately by a factor of more than one
order of magnitude• CTA can resolve the spa@al structure of dwarf
spheroidal to constrain WIMP dark ma/er for theﬁrst @me. Then, we deﬁnitely need informa@on
for density proﬁles of dSphs• By using CTA, we will be able to discriminate atrue dark ma/er model from the others among
WIMP, PBHs, ALPs and so on in near future
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Kaz Kohri (KEK)