Dark Matter from Non-Standard Cosmology

Transcription

1 Dark Matter from Non-Standard Cosmology Bhaskar Dutta Texas A&M University Miami 2016 December 16,

2 Some Outstanding Issues Questions 1. Dark Matter content ( is 27%) 2. Electroweak Scale 3. Baryon Content ( is 5%) 4. Rapid Expansion of the Early Universe 5. Neutrino Mass... Ω b Ω DM Need: Theory, Experiment and Observation 2

3 Presentation Outline What have we learnt so far? LHC, Direct and Indirect Detection Experiments, Planck Data Origin of DM Thermal, Non-thermal, Non-standard cosmology Concluding Insights 3

4 LHC Most models predict: 1-3 TeV (colored particle masses) So far: No colored particle up to 1.6 TeV Non-colored SUSY particles: 100 GeV to 1-2 TeV (Major role in the DM content of the Universe) Weak LHC bound for non-colored particles hole in searches! Trouble in Models with very tight correlation between colored and non-colored particles, e.g., minimal SUGRA/CMSSM LHC + Direct Detection + Indirect Detection+Planck quite constraining (model dependent) 4

5 Direct Detection Experiments Status of New physics/susy in the direct detection experiments: LUX: No signal for Low or High DM mass Astrophysical and nuclear matrix element uncertainties No signal: some particle physics models are ruled out Neutrino floor: A serious concern for the DM experiments Neutrinos arising from astrophysical Sources: Sun, Atmosphere 5

6 Thermal DM 27% Indirect Detection: Fermi < v σ ann Experimental constraints: Large Gamma-rays constraints: Cross-section Dwarf spheroidals, Galactic centeris constrained > < σ v > : smaller than the thermal value ann o Fermi Collaboration: arxiv:

7 γ : Future HAWC 7

8 Latest result from Planck 8

9 Probing Dark Matter Dark Energy 68% Dark Matter + 27% Collider experiments Atoms 5% SM Overlapping region DM content (CMB) + overlapping region: Thermal history, particle physics models, astrophysics 9

10 Dark Matter: Thermal Production of thermal non-relativistic DM: DM + DM f + f Y Y = n s = n g * T s 3 Universe cools (T<m DM ) DM + DM f + f DM + DM f + f dn dt Boltzmann equation DM σv + 3Hn = σv eq = DM 3 3 d p1d p2σve 6 (2π ) 3 3 d p1d p2e 6 (2π ) eq ( E ( E [ n 2 DM + E )/ T + E )/ T n 2 DM, eq ] m/t 3 d pf ( p, t) n = g nos. / vol 3 (2π )

11 Dark Matter: Thermal Freeze-Out: Hubble expansion dominates over the interaction rate Dark Matter content: m DM ndm 1 3H 2 0 ΩDM = ~ ρc = ρ c σv 8πG N freeze out σv T = 3 10 σv f m 20 ~ DM 26 ~ 2 α χ Assuming : 2 f cm 3 α χ ~O(10-2 ) with m χ ~ O(100) GeV leads to the correct relic abundance s m χ Y m/t Y becomes constant for T>T f Y~10-11 for m χ ~100 GeV to satisfy the DM content 11

12 Thermal Dark Matter DM particle + DM Particle SM particles Annihilation Cross-section Rate: < σ ann v > DM DM DM Abundance: 1 ΩDM ~ σv DM We need DM ~ f: SM particles; h, H, A: various Higgs, : f SUSY particle Note: All the particles in the diagram are colorless σv = cm 3 s to satisfy thermal DM requirement 12

13 Thermal Dark Matter Suitable DM Candidate: Weakly Interacting Massive Particle (WIMP) Typical in Physics beyond the SM (LSP, LKP, ) Most Common: Neutralino (SUSY Models) smaller annihilation cross-section Neutralino: Mixture of Wino, Higgsino and Bino Larger annihilation cross-section Ω DM ~ 1 σv Larger/Smaller Annihilation non-thermal DM/non-standard cosmology 13

14 Thermal Dark Matter Dark Matter content: σv f ~ 2 α χ 2 mχ Ω DM ~ 1 σv freeze out T f m 20 ~ DM WIMP Dark Energy 68% Dark Matter 27% σv = cm 3 s Weak scale physics : Atoms 5% α χ ~O(10-2 ) with m χ ~ O(100) GeV leads to the correct relic abundance

15 Status of Thermal DM Thermal equilibrium above T f is an assumption. History of the Universe between the BBN and inflation is unknown Non-standard thermal history at is generic in some explicit UV completions of the SM. Acharya, Kumar, Bobkov, Kane, Shao 08 Acharya, Kane, Watson, Kumar 09 Allahverdi, Cicoli, Dutta, Sinha, 13 DM content can be different in non-standard thermal histories. Barrow 82, Kamionkowski, Turner 90 DM will be a strong probe of the thermal history after it is discovered and a model is established.

16 Non-Thermal DM/Early Matter < σ annv > : different from thermal average, Ω ~ is not 27% Non-thermal DM can be a solution DM from the decay of heavy scalar field, e.g., Moduli decay Decay of moduli/heavy field occurs at: T r [Moduli : heavy scalar fields gravitationally coupled to matter] ~ c 1/ 2 mφ 100TeV 3/ 2 (5MeV) For T r <T f : Non-thermal dark matter T r ~ MeV : Not allowed by BBN 3T r Abundance of decay products (including DM) Yφ 4mφ DM content: also needs to consider the DM annihilation for large Y φ DM 1 σv Moroi, Randall 99; Acharya, Kane, Watson 08, Randall; Kitano, Murayama, Ratz 08; Dutta, Leblond, Sinha 09; Allahverdi, Cicoli, Dutta, Sinha, 13 16

17 Non-Thermal DM DM arising from thermal equilibrium: Ω th T Ω( r 3 ) small unless <σ ann v> is small since T r <T f Tf Moduli decay into dark matter and the correct dark matter content can arise from the decay products: cm 0.23 Ω = σv 3 / s T ( Tf σv T ( T r 26 f 3 ) = 3 10 / Since T r <T f, Larger annihilation cross-section is needed to cut the large abundance (Y φ ) r ) cm s 2. Abundance of Decay products (Y φ ) is small enough, i.e., annihilation is not important any more Freeze-in. 17

18 Benefit of Non-Thermal DM For T r < T f, larger annihilation cross-section is needed for Ω 27% σ v = ann f σ ann v th f T T f r 3T r For T r << T f, Yield Y is small ~10-10 φ ; YDM = Yφ BRφ DM 4mφ DM will be produced without any need of annihilation [Note: For m DM ~10 GeV, Y φ is needed to be ~10-10 to satisfy the DM content] Outcome: Large and small annihilation cross-section from models are okay We may not need any annihilation (Freeze-in) φ DM + Since other particles, abundance (for T r << T f ): The Baryon and the DM abundance are correlated ~ Allahverdi, Dutta, Sinha 11 18

19 DM and Baryon Abundance Ω Ω b DM = 5 27 Baryon abundance: DM abundance: Ω Ω DM b mbnb = ρc mdm n = ρ c DM ρ c =critical density n = number density If m DM ~ few GeV n b ~ n DM (since m b =1 GeV) Same number densities same origin Heavy field decay to DM and generate Baryon abundance (without any annihilation cross-section uncertainty) Solves the coincidence problem Predictive model has been constructed Allahverdi, Dutta, Mohapatra, Sinha, 13 Why baryon and DM abundances are similar? 19

20 Baryogenesis from Moduli N ~ N W extra = λ iαβ N β u c i X α + λ ' ijα d c i d c j X : SM singlet; : Color triplet, hypercharge 4/3 Baryogenesis f rom decays of α + M α X α X α + M X, X ± X, X or N : can be the DM candidate with spin-independent cross-section: Allahverdi, Dutta, Mohapatra, Sinha 12 nb nb ηb = Yφ BrNε s Br N : branching ratio of moduli decay to N 2 β N β N β Assuming that N produces Baryon Asymmetry Y τ ~ 10 ε : asymmetry factor in the N decay , ε<0.1, Br N ~ η B = 9x

21 21 Baryogenesis From X decay Typically, ε 1,2 is O(10-2 ) for CP violating phase O(1) and λ~o(1) Baryogenesis from Moduli β β β α α α α α α β αβ λ λ N N M X X M X d d X u N W c j c i ij c i i extra 2 ' =

22 Non-Thermal msugra/cmssm Aparicio, Cicoli, Dutta, Muia, Quevedo 16 CMSSM/mSUGRA parameters: m 0, m 1/2, A 0, tanβ, sign of µ + T R We consider the case with large <σv> ann This scenario can be realized in the context of LVS 22

23 DM from Early Matter domination Thermal DM abundance from early matter domination (moduli) DM candidate can be Neutralino Kamionkowski and M. S. Turner, 90; Giudice, Kolb, Riotto, 01; Gelmini,Gondolo 06 Small <σ ann v> is allowed by the DM content If the dark matter kinetically decouples prior to reheating Erickcek 15 enhances small-scale perturbations which significantly increase the abundance of microhalos Erickcek, Sigurdson, 11 The boost to the annihilation rate from the microhalos is sufficient to be observed at FERMI 23

24 Non-Standard Cosmology S Correlate DM and DE Bekenstein 93 Koivisto, Wills, Zavala, 13 A new H ( aa aa ) appears (not same as the standard cosmology) The Boltzmann equation also gets modified Catena, Fornengo, Masiero, Pietroni, Rosati 04 Meehan, Whittingham, 15 Modify <σ ann v> to satisfy the DM content 24

25 Changing H before BBN Initial conditions: φφ = , φφ = Y(x) annihilation Dutta, Jiminez, Zavala, 16 25

26 Larger and smaller <σv> annhilation reannihilation 26

27 Conclusion Measurement of DM annihilation cross-section is crucial Large : multicomponent/non-thermal/non-standard cosmology; Small: Non-thermal/early matter domination/non-standard LHC: Determine the model then calculate < σ ann v > DM annihilation from galaxy, extragalactic sources Annihilation into photons: Fermi, CTA, HAWC Annihilation into neutrinos: IceCube 27