スカ ラ ー暗黒物質の 対消滅から 生じ る ガン マ線 藤間 崇 ダラ ム大学 (Durham University) Institute for Particle Physics Phenomenology (IPPP) 益川塾セミ ナ ー T. T., Phys.Rev.Lett. 111 (2013) 091301, A. Ibarra, T. T., M. Totzauer, S. Wild, Phys.Rev.D. 90 (2014) 043526 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 1 / 39 Outline Outline Introduction DM Production Detectability of DM Internal Bremsstrahlung of Majorana DM Scalar DM with vector like fermion Gamma-ray Signatures Summary 藤間 崇 (IPPP) Internal bremsstrahlung χχ → f f γ Monochromatic gamma-rays χχ → γγ, γZ 益川塾セミ ナ ー 22th Sep. 2014 2 / 39 DM production Dark Matter There are many evidences for DM. Rotation curves of spiral galaxies CMB observations Collision of bullet cluster Large scale structure of the universe WIMP: the most promising DM candidate. Many experiments focus on WIMP detection. Direct detection Indirect detection Collider search 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 3 / 39 DM production Thermal Production of DM Thermal Production of DM ⇔ Evolution of number density is determined by Boltzmann equation. dn 2 + 3Hn = −hσv i n2 − neq dt ΓYeq dY =− dx Hx " Y Yeq 2 # same equation −1 , x≡ m , T Γ ≡ hσv i neq , Y ≡ n s Relic density is determined by cross section hσv i. σv is expanded by v . → σv = a + bv 2 + O (v 4) a: s-wave, b: p-wave 1.04 × 109 [GeV−1 ] Ωh2 ≈ √ g∗ mpl hσv i 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 4 / 39 DM production Ωh2 ≈ 0.12 ↔ Thermal Production of DM hσv i ≈ 3 × 10−26 [cm3 /s] = 3 × 10−9 [GeV−2 ] If DM is degenerated, co-annihilation effect should be considered. Other mechanisms Asymmetric Dark Matter DM mass is almost determined to be a few GeV. arXiv:0901.4117, 1308.0338 Production by decay of metastable particle Possible to have DM with rather large ineteractions arXiv:0810.4147 DM mass region 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 5 / 39 Detectability of DM Direct detection Detectability of Dark Matter (i) Direct detection Looking for scattering event with nuclei Nuclei are made from quarks. → interactions with quarks are important. Many experiments are lauching. LUX, XENON100, CDMSII, DAMA, CoGeNT, CRESST, KIMS. detection rate: X ρ⊙ 1 Z dσ dR = vf⊙ (v + ve )d 3 v dER m m dE DM det v >vmin R nuclei d σ/dER : cross section (Particle physics dependence) ρ⊙ , v : DM local density, DM velocity (Astrophysics dependence) 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 6 / 39 Detectability of DM Direct detection DA l it e CDMS M IC 10 1 10 2 CoGeNT (2012) 10 3 CDMS Si (2013) 10 4 10 5 10 6 10 7 10 8 10 9 10 10 10 11 10 12 10 13 10 104 14 ( 2 0 1 2) (2 0 13 ) 012) LE (2 SIMP DAMA 2) P (201 COUP (2012) N-III ZEPLI 009) Ge (2 II S CDM (2012) n100 Xeno (2013) LUX CR ES ST EISS EDELW COHER EN 7 T Be N Neutrinos EU TRI (2011) NG E N O SCATT RI 8B Neutrinos COHER U ENT NE G TERIN TR I NO 1 10 SCAT RI NO NEUT os E NT eutrin NB N C O HE R ING pheric SC ATTER Atmos 100 S and D 1000 WIMP nucleon cross section pb Current limits arXiv:1307.5458 WIMP Mass GeV c2 N σSI . 10−9 [pb] ∼ 10−45 [cm2 ] at mDM ∼ 30 GeV. Results are inconsistent between LUX and DAMA, CoGeNT, CDMS-Si. Neutrino induced background set lower bound. (solar, atmospheric, diffuse supernova neutrinos) 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 7 / 39 Detectability of DM Collider search (ii) Collider search Ex. neutralino in SUSY LHC limit ATLAS-CONF-2013–049 p ℓ ℓ˜ ℓ˜† p χ χ ℓ pp → ℓ˜† ℓ˜ → ℓℓ + missing energy DM mass region mχ . 180 GeV is excluded for mℓ˜ ≈ 300 GeV. 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 8 / 39 Detectability of DM Indirect detection (iii) Indirect detection Propagation of charged particle Propagation equation: ∇ (K (E , x)∇f ) + ∂ [b(E , x)f ] + Q(E , x) = 0 ∂E K (E , x): diffusion coefficient → effect due to magnetic field b(E , x): energy loss coefficient → synchrotron radiation, ICS Q(E , x): source term of DM For DM annihilation nχ2 dN → Q(E , x) = hσv i 2 dE A. Ibarra, ICTP Summer School 2013 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 9 / 39 Detectability of DM Indirect detection Propagation of gamma-ray r⊙ ρ2⊙ d Φγ dN prompt γ: = Jhσvγ i 2 dEγ 8πmχ dEγ r ⊙, ρ⊙ , J: astrophysics dependence mχ , hσvγ i, dN/dEγ : particle physics dependence A. Ibarra, ICTP Summer School 2013 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 10 / 39 Detectability of DM Indirect detection 10-25 10-26 <σv>χχ→γ γ (95% CL) (cm3/s) <σv>γ γ 95% CL Limit (cm3s-1) Upperbounds for cross section into γγ 3.7 year R16 Einasto Profile Observed Upper Limit Expected Limit Expected 68% Containment Expected 95% Containment Weniger [20] Limit 10-27 10-28 10-25 HESS Einasto Fermi-LAT Einasto 10-26 10-27 10-28 10-29 10-30 10 Fermi Coll., arXiv:1305.5597 102 10-29 mχ (GeV) 10-2 10-1 1 10 mχ (TeV) H.E.S.S. Coll., arXiv:1301.1173 σv . 10−29 ∼ 10−26 cm3 /s in DM mass region 10 GeV . mDM . 10 TeV 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 11 / 39 Detectability of DM Gamma-ray spectra Gamma-ray spectra from DM annihilation Line spectrum ex. χχ → γγ, χχ → Z γ 2 suppression factor ∼ αem Internal bremsstrahlung χχ → f f γ When chiral suppression is effective, it becomes important. suppression factor ∼ αem Box type spectrum ex. χχ → SS → 4γ (S: light mediator) if mχ ≫ mS , box type if mχ ≈ mS , Eγ ∼ mχ /2 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 12 / 39 Detectability of DM Gamma-ray spectra Gamma-ray spectra from DM annihilation Bringmann & Weniger H2012L DEE = 0.15 10 DEE = 0.02 1 box B qq,ZZ,W W VI x2dNdx ΓΓ 0.1 0.01 0.02 0.05 0.10 0.20 0.50 1.00 2.00 x = E mΧ T. Bringbann, C. Weniger arXiv:1208.5481 Sharp gamma-ray spectrum is important for DM signal. 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 13 / 39 Detectability of DM Gamma-ray spectra Gamma-ray excesses Significance is 3.3σ at 133 GeV. A few GeV γ-ray excess Fermi Collaboration, arXiv: 1305.5597 Lower significance by Fermi Collaboration. This peak could be a fake. Better instruments are needed. 藤間 崇 (IPPP) D. Hooper et al, arXiv:1402.6703 益川塾セミ ナ ー γ-ray excess around a few GeV hσv ibb ∼ 10−26 cm3 /s which is same order with that needed for thermal relic. 22th Sep. 2014 14 / 39 Detectability of DM Gamma-ray spectra Gamma-ray Background from Galactic Center Acceleration of proton and electron by supermassive black hole Scattering with interstellar medium → producing pion Pion decay π 0 → 2γ Inverse Compton Scattering (e ± γ → e ± γ) gamma-ray source: CMB, starlight Millisecond pulsars → Background modeling 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 15 / 39 Internal Bremsstrahlung Internal Bremsstrahlung 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 16 / 39 Internal Bremsstrahlung Internal Bremsstrahlung of Majorana Dark Matter Consider Majorana DM χ L = y η + χPL f + h.c. Cross section for χχ → f f is expanded by v : σvf f ≈ a + bv 2 σvf f ≈ y 4 mf2 1 1 + µ2 2 y4 + v , 32πmχ2 mχ2 (1 + µ)2 48πmχ2 (1 + µ)2 µ≡ mη2 >1 mχ2 When mf ≪ mχ , s-wave can be negligible. → chiral suppression Relative velocity v in the present universe is v ∼ 10−3 Relic density of DM is determined by p-wave → y is fixed. 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 17 / 39 Internal Bremsstrahlung Internal Bremsstrahlung The total amplitude is separated by two parts. i M = i MFSR + i MVIB Differential cross section (interference term is neglected) d σvfFSR d σvfVIB d σvf f γ fγ fγ = + , dx dx dx FSR : broad spectrum VIB : Eγ ∼ mχ sharp peak spectrum 藤間 崇 (IPPP) 益川塾セミ ナ ー x≡ Eγ , mχ 22th Sep. 2014 18 / 39 Internal Bremsstrahlung Concrete formula for the differential cross section FSR : VIB : dσvfFSR fγ dx dσvfVIB fγ dx ! 2 4mχ2 (1 − x) αem 1 + (1 − x) = σvf f log + (Hadronization) π x mf2 αem y 4 x 2x (1 − x) = − 2 2 32π mχ (µ + 1)(µ + 1 − 2x) (µ + 1 − x)2 µ+1 (µ + 1)(µ + 1 − 2x) log − 2(µ + 1 − x)3 µ + 1 − 2x FSR : model independent 101 100 x2 dN/dx Energy spectra If FSR ≪ VIB, characteristic signal. Majorana DM → chiral suppression µ + µ− (γ) τ + τ− ( γ ) ¯bb(γ,g) 10-1 10-2 10-3 10-2 10-1 100 x = E/mχ arXiv:1203.1312 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 19 / 39 Internal Bremsstrahlung Why hard gamma is emitted? Momentum notation: Initial state: χ(p1 ), χ(p2 ), Final state: f (k1 ), f (k2 ), γ(k3 ) When mf /mχ ≪ 1 and mη /mχ ≈ 1, i i i ≈ 2 ≈ iM ∼ 2 2 2 (p1 − k1 ) − mη mχ − mη − 2mχ Ef −2mχ Ef Emitted f has soft energy. χχ → f f γ is understood as almost 2-body process χχ → (f )f γ. Energy is taken by f γ (Eγ ≈ Ef ≈ mχ ). → Hard gamma emission. 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 20 / 39 Internal Bremsstrahlung How about Dirac DM? 1 y4 + O(v 2) πmχ2 (1 + µ)2 when s-wave exists, FSR is always dominant. For complex scalar DM, p-wave dominant (same as Majorana DM). σvf f = How about real scalar DM? σvf f = y 4 mf2 1 + 2µ 2 1 y 4 mf2 − v 4πmχ2 mχ2 (1 + µ)2 6πmχ2 mχ2 (1 + µ)4 y4 1 + v 4 + O(v 6) 2 4 60πmχ (1 + µ) Summary dominant term 藤間 崇 (IPPP) Majorana Dirac p-wave s-wave real scalar d-wave 益川塾セミ ナ ー compelx scalar p-wave 22th Sep. 2014 21 / 39 Scalar Dark Matter Model Scalar Dark Matter Model 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 22 / 39 Scalar Dark Matter Model The model with scalar Dark Matter New particles Real singlet scalar χ (DM), Z2 = −1 Vector like charged fermion ψ (mediator), Z2 = −1, Y = −1 Interactions LY = y χψPR f + h.c. mχ2 2 λφ † 2 λχ 4 λ 2 † φφ + χ + χ φφ χ + V = mφ2 φ† φ + 2 2 4! 2 where φ is the SM Higgs doublet. DM χ interacts with SM particles through y and λ. (The other parameters: mχ and mψ ) h(x) After φ gets VEV → φ(x) = hφi + √ 2 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 23 / 39 Scalar Dark Matter Model Constraint on coupling λ ✶✵ χ χ ✶ λ ▲❯❳ 10−1 ❳❊◆❖◆✶❚ h 10−2 q q 10−3 1 10 102 mχ [●❡❱] 103 104 The coupling λ should be suppressed from the constraint of direct detection. cλ2 mp4 1 . 7.6 × 10−46 [cm2 ] at mχ ∼30 GeV σp = 4 2 4πmh (mχ + mp ) LUX Collaboration, arXiv: 1310.8214 where c = 0.345 and mp is proton mass. The coupling is limited as λ . 10−2 in all DM mass region. 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 24 / 39 Scalar Dark Matter Model Thermal relic density of DM χχ → hh, χχ → h → f f are subdominant. The most important channel is χχ → f f mediated by ψ. The cross section is expanded as σv = a + bv 2 + cv 4 + O(v 6 ) σvf f = y 4 mf2 y 4 mf2 1 + 2µ 2 1 − v 4πmχ2 mχ2 (1 + µ)2 6πmχ2 mχ2 (1 + µ)4 + 1 y4 v 4 + O(v 6 ), 2 60πmχ (1 + µ)4 µ≡ · when mf ≪ mχ , s-wave and p-wave are negligible. → chiral suppression · This can be interpreted from J and CP conservation. 藤間 崇 (IPPP) 益川塾セミ ナ ー mψ2 mχ2 22th Sep. 2014 25 / 39 Scalar Dark Matter Model Interpretation of d-wave CP and total angular momentum J should be conserved between initial and final states. s-wave initial state: CP=even, J = 0 (J PC = 0++ ) → possible effective operator: OS ∼ χχf f But suppressed by mf since f f corresponds to mass term. p-wave initial state: CP=odd, J = 1 (J PC = 1−+ ) Any J PC = 1−+ bi-linear operator cannnot be constructed for final state. ↔ OP ∼ χ∂i χ f γ i f = 0 Note: p-wave exists for complex scalar DM. 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 26 / 39 Scalar Dark Matter Model Thermal relic density of DM ❚❤❡r♠❛❧ ❨✉❦❛✇❛ ❝♦✉♣❧✐♥❣ y✱ ❢♦r Contours for several mass splittings mψ /mχ = 1.01, 1.1, 2, 3, 5 (λ = 0). micrOmegas is used (co-annihilations are included). λ=0 101 5.0 3.0 2.0 100 mψ /mχ = 1.01 y 1.1 10−1 10−2 1 10 102 103 104 mχ [●❡❱] When masses are degenerated, co-annihilation effect is important. DM mass √ is bounded (mχ . 2 TeV) by perturbativity (y . 4π). 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 27 / 39 Gamma-ray Spectra Gamma-ray Signatures Possible processes χχ → f f γ Internal bremsstrahlung T. T, arXiv:1307.6181 F. Giacchino, L. Lopez-Honorez, M.H.G. Tytgat, arXiv:1307.6480 χχ → γγ, χχ → γZ Monochromatic gamma-ray line A. Ibarra, T. T, M. Totzauer, S. Wild, arXiv:1405.6917 F. Giacchino, L. Lopez-Honorez, M. Tytgat, arXiv:1405.6921 Both gamma-ray emissions are expected to be stronger than Majorana case since y is large enough. 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 28 / 39 Gamma-ray Spectra Internal Bremsstrahlung Internal bremsstrahlung · differential cross section dσvf f γ dx = 2x αem y 4 x (1 − x) − 2 2 4π mχ (µ + 1)(µ + 1 − 2x) (µ + 1 − x)2 Eγ (µ + 1)(µ + 1 − 2x) µ+1 , x≡ − log 2(µ + 1 − x)3 µ + 1 − 2x mχ 101 100 x2 dN/dx · When µ . 4, a sharp peak appears around Eγ ∼ mχ T. Bringmann et al., arXiv:1203.1312 µ + µ− (γ) τ + τ− (γ) ¯bb(γ,g) 10-1 10-2 10-3 10-2 10-1 100 x = E/mχ 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 29 / 39 Gamma-ray Spectra Gamma-ray Lines Line spectra: χχ → γγ, γZ In the limit of v → 0, these analytically can be calculated. Initial state: p1 = p2 = (mχ , 0) ≡ p, Final state: k1 , k2 Flow of calculation 1 G. Bertone et al. arXiv:0904.1442 In general, i M is decomposed as Mµν = p µ p ν A + k1µ k1ν B + k2µ k2ν C + · · · + g µν Aγγ(γZ ) 2 3 where i M = i ǫ∗µ (k1 )ǫ∗ν (k2 )Mµν . only Aγγ(γZ ) remains. Simplify Aγγ(γZ ) by Passarino-Veltman reduction cross sections: σvγγ = α2em y 4 |Aγγ |2 , 32π 3 mχ2 藤間 崇 (IPPP) σvγZ = α2em y 4 tan2 θW 16π 3 mχ2 益川塾セミ ナ ー m2 1 − Z2 |AγZ |2 4mχ 22th Sep. 2014 30 / 39 Gamma-ray Spectra Aγγ = 2 + Li2 Gamma-ray Lines 1 1 1 − Li2 − − 2µArcsin2 √ , µ µ µ 2 µ = mψ /mχ2 > 1 ξ ξ 2 2 B0 mZ2 ; 0, 0 − B0 mZ2 ; mψ , mψ 4−ξ 4−ξ 2ξ 2µξ 2 2 2 2 + − B0 mχ ; 0, mψ B0 4mχ2 ; mψ , mψ (4 − ξ)(1 − µ) (4 − ξ)(1 − µ) 2 2 2 2 4 − 4µ − ξ , mψ , mψ +mψ C0 mZ2 , 4mχ2 , 0; mψ 1−µ 2 mψ m2 (4 + ξ)(−2 + 2µ + ξ) 2 2 + C0 −mχ2 + Z , mχ2 , 0; mψ , 0, mψ 2 (1 − µ)(4µ + ξ) 2 2 mZ2 4ξ(1 + µ) 2 2 2 2 2 ξ(1 + µ) C0 −mχ + − , mχ , mZ ; 0, mψ , 0 +mχ 2(1 + µ) (4 − ξ)(4µ + ξ) 2 mZ2 4(1 + µ) 2 2 2µ(1 − µ) + ξ 2 2 2 2 C0 −mχ + +mχ − , mχ , mZ ; mψ , 0, mψ 2(1 − µ) 4−ξ 2 AγZ = 2 − where B0 and C0 are Passarino-Veltman integrals. when ξ ≡ mZ2 /mχ2 → 0, AγZ → Aγγ 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 31 / 39 Gamma-ray Spectra Cross Sections Cross sections DM mass dependence µ = 1.1, y = 1 µ = 25, y = 1 10−28 10−24 10−29 10−30 10−26 10−27 2 · γγ hσvi [cm3 /s] hσvi [cm3 /s] 10−25 f f¯γ 10−28 10−29 10−32 10−33 γZ 10−30 10−34 10−31 1 10 10−35 1 10 102 103 104 2 · γγ 10−31 mχ [GeV] γZ f f¯γ 102 103 104 mχ [GeV] Mass splitting is fixed to µ = 1.1 (left), µ = 25 (right). σvγγ and σvγZ are same order. Detectability of χχ → γγ, γZ depends on experimental energy resolution. 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 32 / 39 Gamma-ray Spectra Cross Sections Cross sections µ = mψ2 /mχ2 dependence mχ = 150 GeV, y = 1 mχ = 500 GeV, y = 1 10−26 10−27 f f¯γ 10−27 10−29 2 · γγ hσvi [cm3 /s] hσvi [cm3 /s] f f¯γ 10−28 10−28 10−29 γZ 10−30 10−31 2 · γγ 10−30 γZ 10−31 10−32 10−32 10−33 10−33 10−34 1 10 100 1 µ 10 100 µ DM mass is fixed to 150 GeV (left) and 500 GeV (right). when µ & 10, σvf f γ < σvγγ,(γZ ) due to µ dependence of the cross sections. σvf f γ ∝ 藤間 崇 (IPPP) y4 1 , µ4 mχ2 σvγγ , σvγZ ∝ 益川塾セミ ナ ー y4 1 µ2 mχ2 22th Sep. 2014 33 / 39 Gamma-ray Spectra Cross Sections Total Energy spectrum (10% energy resolution) d hσv if f γ 1 d hσv iγγ d hσv iγZ dNγ = +2 + dx hσv i dx dx dx µ = 1.1 µ=4 101 101 10−1 100 Total f f¯γ γγ 10−2 x2 dNγ /dx x2 dNγ /dx 100 10−3 Total γγ 10−1 f f¯γ 10−2 10−3 γZ 10−4 0.1 γZ 10−4 0.1 1 x = Eγ /mχ µ=9 x = Eγ /mχ µ = 25 101 101 Total f f¯γ 10−2 γγ 10−3 10−1 f f¯γ 10−2 γγ 10−3 γZ 10−4 0.1 1 γZ 10−4 0.1 x = Eγ /mχ 藤間 崇 (IPPP) Total 100 x2 dNγ /dx x2 dNγ /dx 100 10−1 1 1 x = Eγ /mχ 益川塾セミ ナ ー 22th Sep. 2014 34 / 39 Gamma-ray Spectra Cross Sections Comparison with Gamma-ray Experiments mψ /mχ = 1.1, λ = 0, y = yt❤❡r♠❛❧ ❋❡r♠✐✲▲❆❚ ✴ ❍✳❊✳❙✳❙ ❋❡r♠✐✲▲❆❚ ✴ ❍✳❊✳❙✳❙ s❝❛❧❛r ❉▼✿ 10−26 f f¯γ s❝❛❧❛r ❉▼✿ ❈❚❆ 10−27 ▼❛❥♦✳ ❉▼✿ 10−28 f f¯γ s❝❛❧❛r ❉▼✿ 10−29 hσvi [❝♠3 /s] hσvi [❝♠3 /s] 10−26 mψ /mχ = 3, λ = 0, y = yt❤❡r♠❛❧ 2 · γγ ▼❛❥♦✳ ❉▼✿ 10−27 s❝❛❧❛r ❉▼✿ f f¯γ 10−28 10−29 2 · γγ ▼❛❥♦✳ ❉▼✿ 10−30 10−30 102 103 mχ ❬●❡❱❪ ❈❚❆ 2 · γγ 104 2 · γγ ▼❛❥♦✳ ❉▼✿ 102 f f¯γ 103 mχ 104 ❬●❡❱❪ Scalar DM χ is testable by future gamma-ray experiments such as CTA. Future experiments Energy range [GeV] Angular res [deg] Energy res [%] 藤間 崇 (IPPP) GAMMA400 0.1-3000 ∼0.01 ∼1 益川塾セミ ナ ー DAMPE 5-10000 0.1 at 100 GeV ∼1 at 800 GeV CTA >10 0.1 15 22th Sep. 2014 35 / 39 Constraints and Prospects Constraints DM relic density (Ωh2 ≈ 0.12) √ Perturbativity (y . 4π, 4π) Direct detection Collider search (ψψ production) Indirect detection (e + e − , anti-proton, gamma-ray) χχ → f f γ, f f Z For mψ /mχ = 1.01 For mψ /mχ = 1.1 mψ /mχ = 1.01, λ = 0 ✶✵ ✭♠❛①✮ mψ /mχ = 1.1, λ = 0 ✶✵ P❆▼❊▲❆ p¯/p λ = λ▲❯❳ (mχ ) 10−24 P❆▼❊▲❆ p¯/p ❋❡r♠✐✲▲❆❚ ❞✇❛r❢s 102 103 mχ [●❡❱] → weak constraint 藤間 崇 (IPPP) 104 hσvi✭♠❛①✮ [cm3 /s] y y ✶ 10−1 yt❤❡r♠❛❧ ❆▼❙ e+ /e− yt❤❡r♠❛❧ ❆▼❙ e+ /e− ✶ 10−1 102 103 mχ [●❡❱] 益川塾セミ ナ ー 104 (b¯b) 10−25 10−26 10−27 20 W +W − P❆▼❊▲❆ p¯/p (b¯b) hh 102 mχ ZZ ❬●❡❱❪ 22th Sep. 2014 103 36 / 39 Constraints and Prospects Allowed parameter space and future prospects λ = 0.0 λ = 0.03 Only narrow parameter region is remaining and will be tested by CTA and XENON1T. 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 37 / 39 Summary Summary Gamma-ray signatures from DM annihilations are characteristic. In the toy model we considered here, the annihilation cross section is dominated by d-wave. → Large cross sections for sharp gamma-rays are obtained. Only small parameter space is remaining. Most of the parameter space is testable by future gamma-ray and direct detection experiments. Future work Enhancement of internal bremsstrahlung of Majorana DM by cosidering co-annihilation. Strong ν flux via electroweak bremsstrahlung? χχ → ℓℓZ , χχ → ℓνW + 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 38 / 39 Backup Backup slide Fitting to 130 GeV gamma-ray excess 10-5 Fermi data 90.0%CL Fermi data 68.3%CL yL = 1.0 yL = 1.5 yL = 2.0 yL = 3.0 yL = 4.0 8 Fermi data Background VIB+FSR+Background VIB+FSR 7 6 µ Eγ2dΦγ/dEγ [GeVcm-2s-1sr-1] 10-4 5 4 10-6 3 2 -7 10 100 101 102 103 Eγ [GeV] 1 100 120 140 160 mχ [GeV] 180 200 χ2min = 65.57 (51 d.o.f) at mχ = 155 GeV, µ = 2.05. hσv if f γ = 4.72 × 10−27 cm3 /s. 藤間 崇 (IPPP) 益川塾セミ ナ ー 22th Sep. 2014 39 / 39
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