Overview of dark matter candidates Chang Sub Shin (APCTP) 2 nd KR-LHC TH-EXP Cross Seminar At SNU, May. 26, 2017
Dark matter paradigm
Dark matter paradigm
Existence of dark matter New Physics beyond the Standard Model Gravitational interacting, Stable, Charge neutral, Non-baryonic, 23-25% of total energy, Non dissipative, Cold p DM = w ρ DM , w ' 0 ( Weak lensing, Galaxy rotation Large scale Bullet clusters curves structure, CMB Evidences Gpc scales kpc Mpc
Existence of cold dark matter ? 10 5 Gravitational interacting, 10 4 Stable, P(k,z=0) [Mpc 3 ] 10 3 Charge neutral, Non-baryonic, 10 2 SDSS DR7 (Reid et al. 2010) LyA (McDonald et al. 2006) 23-25% of total energy, ACT CMB Lensing (Das et al. 2011) ACT Clusters (Sehgal et al. 2011) CCCP II (Vikhlinin et al. 2009) Non dissipative, 10 1 BCG Weak lensing (Tinker et al. 2011) ACT+WMAP spectrum (this work) Cold p DM = w ρ DM , w ' 0 ( 10 − 3 10 − 2 10 − 1 10 0 = 2 π / λ k [Mpc − 1 ] ( depending on ti e tj me of Horizon en ts y ) Cold DM Warm DM λ = 1 /H ( t entry ) ( Weak lensing, Galaxy rotation Large scale Bullet clusters curves structure, CMB Evidences Gpc scales kpc Mpc missing satellite, too big to fail, cusp-core problems
Missing satellite, too big to fail problems A quantitative comparison of # satellites at r < 400 kpc. A rich galaxy cluster halo A 'Milky Way' halo Klypin et al. 1999 Springel et al 2001 Power et al 2002 simulated Observed Number 10 8 10 9 10 10 10 11 `MW’ 10 12 100 0.9" kpc/h Resolution: baryonic feedback processes (which suppress the star formation) is most efficient in low mass (luminosity) satellites. Reflected, and select most massive satellites of MW Moore et al 1999 Satellite Luminosity function observed simulated
Missing satellite, too big to fail problems Predicted most luminous satellite galaxies are too massive (not observed) to fail star formations [Boylan-Kolchin, Bullock, Kaplinghat 1111.2048] Satellite Luminosity function Most massive satellites of MW observed simulated
Cusp-core problem ρ 0 ρ NFW ( r ) = r s (1 + r r r s ) 2 [1011.2777]
Cusp-core problem (diversity of rotation curves) ρ 0 ρ NFW ( r ) = r s (1 + r r r s ) 2 Al [1504.01437] the Oman et al. (2015)
Existence of WIMP dark matter ? DM SM DM SM Elastic scattering Annihilation Weak lensing, Galaxy rotation Large scale Bullet clusters curves structure, CMB Evidences Gpc scales kpc Mpc No clear evidence yet
Nature of the dark matter ? Is DM a particle ? spin , mass, compositions ? Why is it stable ? gauge/global, continuous/discrete symmetries ? What are the interactions between DM and the SM particles besides gravity (like strong/weak interactions) ? What is the production mechanism of DMs at the early Universe ? Why 25% of total mass of the present Universe ? How can we detect it at sub kpc scales (at the earth) ? What are the additional predictions ? solving several small scale problems Weak lensing, Galaxy rotation Large scale Bullet clusters curves structure, CMB Evidences Gpc scales kpc Mpc
Nature of the dark matter ? ρ tot = 1 . 2 ⇥ 10 − 6 GeV / cm 3 ρ DM = m DM ¯ ¯ n DM ' 0 . 25¯ (observation) Weakly Interacting Primordial Black Hole Massive Particle (PBH) Fuzzy DM (FDM) QCD Axion (WIMP) Candidates 10 57 GeV = M sun = 10 33 g DM mass 10 -5 eV keV 100 GeV 10 -22 eV Warm Dark Matters Strongly Asymmetric (WDM) Interacting Dark Matter Massive (ADM) Particle (SIMP) Evolutions of each DMs are different, and give (possibly) different predictions for small scales Weak lensing, Galaxy rotation Large scale Bullet clusters curves structure, CMB Evidences Gpc scales kpc Mpc
Coincidence ? Ω DM ' 0 . 25 • WIMP g 4 h σ ann v i fr ' 1 ✓ 3 ⇥ 10 − 26 cm 3 / sec ◆ ( g ⇠ 0 . 1) Ω DM = 0 . 25 m 2 8 π h σ ann v i fr weak • QCD Axion ◆ 7 / 6 ✓ f a p f a ⇠ m weak M Pl α a = 0 . 01 � 1 Ω DM = 0 . 25 α a p 10 10 GeV • SIMP ◆ ✓ 3 ⇥ 10 − 52 cm 6 / sec 1 ◆ 1 / 2 ✓ 50 MeV h σ 3 → 2 v 2 i fr ' m DM ⇠ m π Ω DM = 0 . 25 m 5 ⇠ � m DM h σ 3 → 2 v 2 i fr DM • Asymmetric DM Ω DM = O ( Ω baryon ) Ω DM = (4 � 5) Ω baryon • Relativistic freeze-out DM ⇣ m DM 230 ⌘ Ω DM = m WDM ⇠ O (keV) g ∗ ( T dec ) 2 keV p • Fuzzy DM ◆ 2 ⇣ ✓ F m DM ⌘ 1 / 2 Ω DM = 0 . 25 F ⇠ M GUT � M Pl 10 17 GeV 10 − 22 eV
WIMP
WIMP direct detection [1705.06655]
WIMP direct detection [Mahmoudi, Arbey 1411.2128] O 10 − 10 pb = 10 − 46 cm 2 PMSSM CMSSM
WIMP indirect detection 10 � 22 MW Halo: Ackermann+ (2013) MW Center: Gomez-Vargas+ (2013) dSphs: Ackermann+ (2015) 10 � 23 Unid. Sat.: Bertoni+ (2015) Virgo: Ackermann+ (2015) h σ v i [cm 3 s � 1 ] Isotropic: Ajello+ (2015) 10 � 24 X-Correl.: Cuoco+ (2015) APS: Gomez-Vargas+ (2013) [Fermi-LAT 1605.02016] 10 � 25 Thermal Relic Cross Section 10 � 26 (Steigman+ 2012) Daylan+ (2014) Calore+ (2014) b ¯ Gordon & Macias (2013) Abazajian+ (2014) b 10 � 27 10 1 10 2 10 3 10 4 m χ [GeV]
WIMP paradigm SM SM wimp W(Z) portal, Higgs portal, Z’ portal wimp Letpo-philic, flavor-isospin dependent, s-(p-,d-) wave annihilation, spin (in)dependent (in)elastic scattering, General effective operators
Stjlm WIMP paradigm SM Ex) RH sneutrinos (WIMP) with RH neutrinos (DR) in SM U(1) B-L conserving SUSY Dirac leptogenesis model [Choi, Chun, CSS 1211.5409] wimp W(Z) portal, Higgs portal, Z’ portal wimp Letpo-philic, flavor-isospin DR dependent, s-(p-,d-) wave annihilation, DR spin (in)dependent (in)elastic scattering, General effective operators
Stjlm WIMP paradigm wimp wimp New constraints/predictions DR DR from cosmology DR New signatures for the indirect detection of DM SM
DR contributes to N eff DR DR DR DR DR DR DR DR Fluid Free streaming [Bell, Pierpaoli, Sigurdson astro-ph/0511410] N e ff = N SM + N fluid = 3 N fluid = 0 e ff
Finite DR mass (~eV) : Hot DM DRs : relativistic during RD ( T > eV), non-relativistic after matter- radiation equality (T < eV), and they contribute to the total dark matter density at present. For scales that enter the horizon before matter- radiation eq, HDM perturbations are suppressed à suppression of matter power spectrum δρ DM δρ wimp < δρ wimp ' ρ wimp + ρ HDM ρ DM ρ wimp DR DR DR DR wimp Growing perturbation by self gravity
DR-WIMP interactions Sizable interactions between DR and DM give dark acoustic oscillation (DAO) ( ) or the drag effect ( ) for the evolution of Γ ⇠ H Γ � H ! Γ < H matter perturbations Unbroken hidden SU(N) 0 . 1 [Lesgourgues, Marques-Tavares, Schmaltz 1507.04351] 0 . 0 Unbroken hidden U(1) P ( k ) / P ( k ) [ Λ CDM] − 1 [Ko, Tang 1608.01083] − 0 . 1 …. DR − 0 . 2 − 0 . 3 DR dragging DR − 0 . 4 DR wimp − 0 . 5 10 − 4 10 − 3 10 − 2 10 − 1 10 0 10 1 k [ h/ Mpc] DR tuning Γ ( T ) ' H ( T ) for T & T eq Growing perturbation by self gravity
Metastable DR (m > MeV): messenger WIMP DM Annihilation at the galaxy center can generate (partial) directional cosmic ray signals. D. Kim, JCP & S. Shin [1702.02944] � “ Transporting ” (effectively) DM at the GC to the vicinity of the Earth via a “proxy” ψ � 2𝜓 ℎ → 2𝜔 & 𝜔 → 𝑓 + 𝑓 − 𝜓 𝑚 + … � 𝜓 ℎ : heavier DM, dominant relic, no direct coupling to SM � 𝜔 : heavy “ meta ” -stable dark sector state Transporting � 𝜓 𝑚 : lighter DM, subdominant relic, direct coupling to SM DM density Retarded decay Transporting via 𝜔 𝑓 + 𝜔 DM clump 8.5 kpc @ GC [JC Park’s slide at Pheno 17]
Axion-like DM ( QCD axion, Fuzzy DM )
(ultra) light pseudo scalar fields Very light compared to the background temperature • m a ⌧ eV ⇣ ⌘ Still can be cold dark matter by “coherent oscillation” • m a = Λ 2 F L = 1 2 F 2 ( ∂ µ θ ) 2 � Λ 4 (1 � cos θ ) ( a ( x ) ⌘ F θ ( x ) θ ( t, x ) ' θ ini cos( m a t ) R ( t ) − 3 / 2 for m a & H ( t ) ( p DM = w ρ DM , w ' cos 2 m a t t h w i t = 0 for m a � H ( t ) 5 , θ F ˜ ( ∂ µ θ ) J µ Cosmologically stable F, · · · • a /F 2 ) − 1 = ( F/ 10 10 GeV) 2 (10 − 4 eV /m a ) 3 10 27 years τ a ' ( m 3 θ ini
QCD axion Solution to the strong CP problem (it is also the origin of the axion mass) • g 2 32 π 2 θ G a ˜ G a with h θ i = 0 s | θ obs | < 10 − 10 ) Λ ⇠ Λ QCD ⇠ 100 MeV ✓ 10 11 GeV ✓ 10 11 GeV ◆ ◆ m a ' 10 − 5 eV ' (2cm) − 1 F F microwave ◆ 7 / 6 � ✓ F h θ 2 � Ω DM ' 0 . 25 ini i osc . + α dec . 10 12 GeV The axion DMs (around the earth) can be converted to photons in • strong magnetic fields C γ e 2 a F E · B 16 π 2
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