Particle Dark Matter III Kathryn M Zurek LBL Berkeley Thursday, June 25, 15
Astrophysical and Cosmological Constraints on the Dark Matter (The DM sector is not as unconstrained as you thought) Thursday, June 25, 15
Check Cosmology What are good things to look for? We have a lot of information about the DM sector from the time of BBN (t = 1 sec) BBN CMB LSS Supernovae Galaxy curves (baryons) (curvature) (matter) (DE) (matter) Thursday, June 25, 15
1. BBN Baryon density Ω b h 2 0.005 0.01 0.02 0.03 0.27 4 He 0.26 0.25 Y p D 0.24 ___ H 0.23 10 − 3 Late-decaying or D/H p CMB BBN 10 − 4 3 He/H p annihilating DM can 10 − 5 10 − 9 ionize nuclei and 5 7 Li/H p 2 change the predictions 10 − 10 1 2 3 4 5 6 7 8 9 10 Baryon-to-photon ratio η × 10 10 Figure 20.1: The abundances of 4 He, D, 3 He, and 7 Li as predicted by the standard of BBN Kawasaki, Kohri, Moroi, hep-ph/0408426 BBN occurs at T ~ 1 MeV or t ~ 1 sec Particularly relevant for decay to gravitinos or for MeV mass (or lighter) DM Thursday, June 25, 15
2. CMB epoch CMB multipoles + LSS are consistent with baryon-photon fluid plus non-interacting matter matter- radiation Baryon density equality --> measurement of matter density sound speed = baryon to photon ratio Thursday, June 25, 15
2. CMB epoch DM interactions with baryo-photon fluid would damage agreement with observations of CMB Rutherford scattering: α 2 em � 2 d σ Xb = rel sin 4 ( θ ∗ / 2) , 4 µ 2 b v 4 d Ω ∗ This constrains DM milli-charge McDermott, Yu, KZ 1011.2907 Thursday, June 25, 15
3. DM Annihilations and CMB epoch A high rate of DM annihilations would inject ionizing photons into the CMB Epoch of *re*combination, not de-combination 6000 no DM annihilation DM 1 GeV e + e - 1000 GeV W + W - 2500 GeV XDM µ + µ - γ 4000 L(L+1) C L / 2 π [ µ K 2 ] γ DM Direct 2000 Final State photons Radiation 0 0 500 1000 1500 2000 Finkbeiner, Padmanabhan, Slatyer 0906.1197 L Thursday, June 25, 15
3. DM Annihilations and CMB epoch Powerful constraint on ionizing radiation injection rate = annihilation rate Finkbeiner, Padmanabhan, Slatyer 0906.1197 2 1 5 Ruled out by WMAP5 8 3 4 6 7 10 9 11 12 1 XDM µ + µ - 2500 GeV, BF = 2300 13 2 µ + µ - 1500 GeV, BF = 1100 3 XDM µ + µ - 2500 GeV, BF = 1000 4 XDM e + e - 1000 GeV, BF = 300 5 XDM 4:4:1 1000 GeV, BF = 420 Planck 6 e + e - 700 GeV, BF = 220 forecast 7 µ + µ - 1500 GeV, BF = 560 CVL 8 XDM 1:1:2 1500 GeV, BF = 400 9 XDM µ + µ - 400 GeV, BF = 110 10 µ + µ - 250 GeV, BF = 81 11 W + W - 200 GeV, BF = 66 12 XDM e + e - 150 GeV, BF = 16 13 e + e - 100 GeV, BF = 10 Thursday, June 25, 15
4. Large Scale Structure Dark matter halos are not exactly spherical! If DM had strong self-interactions, the resulting halo would be approx spherical Thursday, June 25, 15
4. Large Scale Structure Places constraint on DM self-interactions Require one scattering or fewer per DM particle over the age of the halo α 2 em � 4 d σ XX = rel sin 4 ( θ ∗ / 2) , m 2 X v 4 d Ω ∗ Feng et al, 0905.3039 n X σ XX v . τ − 1 halo Thursday, June 25, 15
4. Astrophysical objects If DM interacts with nucleons in object, it can scatter, lose energy and become trapped DM slowly thermalizes with object and sinks to center Thursday, June 25, 15
Annihilation Inside Equilibrium achieved when capture and N = C − AN 2 = 0 annihilation balance ˙ As long as capture and annihilation rate is large enough, this is achieved AN 2 = C tanh 2 ( t � / τ E ) √ CA τ E = Capture rate prop to scattering rate � � � 270 km / s � � 1 GeV � C � ≃ 1 . 3 × 10 25 s − 1 ρ DM 0 . 3 GeV / cm 3 v ¯ m DM �� � � � � σ H σ He × S ( m DM /m H ) + 1 . 1 S ( m DM /m He ) 10 − 40 cm 2 16 × 10 − 40 cm 2 Gould, ApJ 388 , 338 (1991) Thursday, June 25, 15
Collection Inside What if annihilation does not occur? (ADM) Then only collection occurs N = Ct ≃ � 100 GeV � � � � � � � t ρ X σ XB N X ≃ 2 . 3 × 10 44 . 10 3 GeV / cm 3 2 . 1 × 10 − 45 cm 2 10 10 years m X Not very much mass, but if x-sect large ∼ 10 57 GeV /M � enough, may have impact Scalar DM may form black hole; fermion DM may alter stellar evolution Thursday, June 25, 15
Black Hole Formation When collected DM a) self-gravitates AND b) exceeds Chrandrasekhar number, then form a black hole � 2 � 2 � M pl � 100 GeV E ∼ − GNm 2 + 1 N boson ≃ 1 . 5 × 10 34 ≃ R. Cha m m R ≃ � 100 GeV � � � � � � � t ρ X σ XB N X ≃ 2 . 3 × 10 44 . 10 3 GeV / cm 3 2 . 1 × 10 − 45 cm 2 10 10 years m X -40 10 CDMS -41 10 -42 10 Excluded Black hole would -43 10 with a BEC -44 10 -45 10 eat neutron star 2 ) -46 10 σ n (cm -47 10 J0437-4715 -48 10 9 Years t=6.69 × 10 -49 10 6 K T=2.1 × 10 -50 10 3 ρ X =0.3 GeV/cm -51 10 -52 10 McDermott, Yu, KZ 1103.5472 -3 -2 -1 0 1 2 3 4 5 10 10 10 10 10 10 10 10 10 m X (GeV) Thursday, June 25, 15
Stellar Constraints Disrupt main sequence evolution Zenter and Hearin, 1110.5919 Taoso et al, 1005.5711 Thursday, June 25, 15
Dark Matter Model Dynamics (Looking beyond the vanilla WIMP paradigm) Thursday, June 25, 15
DM Paradigm: recap Usual picture of dark matter is that it is: single stable (sub-?) weakly interacting neutral Supersymmetry and axions fit the bill. Thursday, June 25, 15
Hidden Dark Worlds Our thinking has shifted From a single, stable weakly interacting particle ..... (WIMP, axion) Models: Supersymmetric light DM sectors, Secluded WIMPs, WIMPless DM, Asymmetric DM ..... Production: freeze-in, freeze-out and decay, asymmetric abundance, non-thermal mechanisms ..... M p ∼ 1 GeV ...to a hidden world Standard Model with multiple states, new interactions Thursday, June 25, 15
Our Thinking Has Shifted: Why? Perhaps overly influenced by only a couple of paradigms? Overly single minded focus? Thursday, June 25, 15
Our Thinking Has Shifted: Why? Anomalies have forced us in this direction Two examples: PAMELA, (DAMA, CoGeNT) Fitzpatrick, KZ 1007 .5325 s p H cm 2 L 10 - 39 10 - 40 4 8 10 12 6 m DM H GeV L PAMELA: large rate, no hadronic activity DAMA/CoGeNT: large scattering cross-section Thursday, June 25, 15
Our Thinking Has Shifted: Why? Two examples: PAMELA, (DAMA, CoGeNT), neither explainable with minimal SUSY ✓ Z d Cirelli et al 0809.2409 ◆ 2 ✓ tan � ◆ 2 ✓ 100 GeV ◆ 4 � n ⇡ 8 . 3 ⇥ 10 − 42 cm 2 10 1 10 - 2 30 0 . 4 30 m H ATIC BETS08 08 EC 10 sec 10 - 3 fraction PAMELA 08 p ê p 10 2 3 Ê Ê ÊÊÊ Ê Ê Ê Ê Ê 10 - 4 Ê Ê Ê Ê 1 background? Ê Ê Ê background? 10 - 5 0.3 10 3 10 10 2 10 3 10 4 1 10 10 2 10 3 10 4 1 10 10 2 10 3 10 4 GeV GeV p kinetic energy in GeV SUSY: annihilation to W’ s results in DAMA/CoGeNT: Z-pole and collider hadronic activity (anti-protons, not constraints on Higgs sector background? observed) Thursday, June 25, 15
Our Thinking Has Shifted: Why? Two examples: PAMELA, (DAMA, CoGeNT), neither explainable with minimal SUSY χ e, n χ 1 χ A’ γ , Z χ 1 γ , Z A’ χ χ 2 χ e, n χ 2 χ γ , Z A’ χ 1 σ SI ' g 2 n g 2 χ m 2 r π m 4 A 0 ◆ 4 ⌘ 2 ✓ 8 GeV m A 0 < 2 m π ⇠ 10 − 40 cm 2 ⇣ g n g χ 10 − 4 m A 0 Solution: light forces Solution: light forces Thursday, June 25, 15
Our Thinking Has Shifted: Why? Simple, attractive, phenomenologically viable models exist Example: ADM. Start with a single DM particle X, and one discovers you need more particles n X ∼ 10 − 10 T 3 Thursday, June 25, 15
Our Thinking Has Shifted: Why? Simple, attractive, phenomenologically viable models exist Example: ADM. Start with a single DM particle X, and one discovers you need more particles n X ∼ 10 − 10 T 3 Thursday, June 25, 15
Experimental Implications of Dark Sectors and Forces Thursday, June 25, 15
Exp. Implications of Dark Sectors .... .... with dark forces Direct Detection Intensity experiments DM self-scattering and halo shapes Thursday, June 25, 15
Direct Detection Mediates _large_ scattering cross-sections σ SI ' g 2 n g 2 χ m 2 r χ e, n χ 1 π m 4 γ , Z A’ A 0 ◆ 4 ⌘ 2 ✓ 8 GeV ⇠ 10 − 40 cm 2 ⇣ g n g χ 10 − 4 m A 0 χ e, n χ 2 Simplified model gives rise to many effects χ A’ χ χ γ , Z f χ 1 χ 1 A’ γ , Z χ χ 2 χ χ ¯ γ , Z f χ A’ χ 1 χ 2 Thursday, June 25, 15
Connection to Intensity Experiments Dark sectors may be more efficiently produced in low energy intensity experiments Once above mass scale of mediator, σ ∼ g 4 production x-sect scales as E 2 Low energy, very intense beams generated increased sensitivity Prefer beam energy sitting on mass of mediator E ∼ m M Thursday, June 25, 15
Connection to Intensity Experiments Dark sectors may be more efficiently produced in low energy intensity experiments 0.01 0.1 1 0.01 0.01 A 0 10 - 3 10 - 3 D 10 - 4 10 - 4 C e � e � B 10 - 5 10 - 5 e A 10 - 6 10 - 6 γ 10 - 7 10 - 7 Z E 10 - 8 10 - 8 0.01 0.1 1 mA' ê GeV Bjorken, Essig, Schuster, Toro Thursday, June 25, 15
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