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Bhaskar Dutta

Texas A&M University

Dark Matter from Non-Standard Cosmology

December 16, 2016

Miami 2016

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QuestionsSome Outstanding Issues

1. Dark Matter content ( is 27%)

2. Electroweak Scale

3. Baryon Content ( is 5%)

4. Rapid Expansion of the Early Universe

5. Neutrino Mass...

Need: Theory, Experiment and Observation

DMΩ

bΩ

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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

Presentation Outline

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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+Planckquite constraining (model dependent)

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Direct Detection ExperimentsStatus 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

Indirect Detection: Fermi

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: smaller than the thermal valueoannv >< σ

>< vannσ

Thermal DM 27%

Gamma-rays constraints: Dwarf spheroidals, Galactic center

Experimental constraints:

Fermi Collaboration: arXiv:1503.02641

LargeCross-sectionis constrained

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γ : Future

HAWC

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Latest result from Planck

http://public.planck.fr/images/resultats/2014-matiere-noire/plot_constraints_planck2014.jpg

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Probing Dark Matter

SM

Dark Energy68%

Atoms5%

Dark Matter27% +

Collider experiments

Overlapping region

DM content (CMB) + overlapping region:

Thermal history, particle physics models, astrophysics

Dark Matter: ThermalProduction of thermal non-relativistic DM:

ffDMDM +⇔+

ffDMDM +⇒+

Universe cools (T<mDM)

ffDMDM +⇔+

Boltzmann equation

][3 2,

2eqDMDMeqDM

DM nnvHndt

dn−−=+ σ

∫

∫+−

+−

=

6

/)(2

31

3

6

/)(2

31

3

)2(

)2(21

21

π

πσ

σ TEE

TEE

eq epdpd

vepdpd

vvolnostppfdgn /.

)2(),(

3

3

≡= ∫ π

m/T

3* Tgn

snY

s

==Y

Dark Matter: Thermal

Freeze-Out: Hubble expansion dominates over the interaction rate

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v1~DM σρc

DMDM nm=Ω

20~ DM

fmT

Dark Matter content:

Assuming : 2

2

~vχ

χασ

mf

αχ~O(10-2) with mχ ~ O(100) GeVleads to the correct relic abundance

m/T

freeze out

scm3

26103v −×=σY becomes constant for T>Tf

Nc G

Hπ

ρ83 2

0=

Y

Y~10-11 for mχ~100 GeVto satisfy the DM content

Thermal Dark Matter

DM particle + DM Particle SM particles

Annihilation Cross-section Rate:

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>< vannσ

DM

DM

DM

DM

f: SM particles; h, H, A: various Higgs, : SUSY particleNote: All the particles in the diagram are colorless

v1~DM σ

Ω

DM Abundance:

f~

scm3

26103v −×=σWe need to satisfy thermal DM requirement

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Suitable DM Candidate: Weakly Interacting Massive Particle (WIMP)

Typical in Physics beyond the SM (LSP, LKP, …)

Most Common: Neutralino (SUSY Models)

Neutralino: Mixture of Wino, Higgsino and Bino

Larger/Smaller Annihilation non-thermal DM/non-standard cosmology

Thermal Dark Matter

Larger annihilationcross-section

smaller annihilationcross-section

v1~DM σ

Ω

Thermal Dark Matter

Dark Energy68%

Atoms5%

Dark Matter27%

v1~DM σ

Ω

20~ DM

fmT

Dark Matter content:

Weak scale physics :

2

2

~vχ

χασ

mf

αχ~O(10-2) with mχ ~ O(100) GeVleads to the correct relic abundance

freeze out

scm3

26103v −×=σWIMP

Non-standard thermal history at is generic in some explicit UV completions of the SM.

fT

Acharya, Kumar, Bobkov, Kane, Shao’08Acharya, Kane, Watson, Kumar’09Allahverdi, Cicoli, Dutta, Sinha,’13

Status of Thermal DMThermal equilibrium above is an assumption.

History of the Universe between the BBN and inflation is unknown

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.

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Non-Thermal DM/Early Matter

Decay of moduli/heavy field occurs at:

)MeV5(TeV100

~2/3

2/1

φmcTr

Tr ~ MeV : Not allowed by BBN

[Moduli : heavy scalar fields gravitationally coupled to matter]

>< vannσ : different from thermal average, is not 27% Non-thermal DM can be a solution

DM from the decay of heavy scalar field, e.g., Moduli decay

For Tr<Tf: Non-thermal dark matter

v1~DM σ

Ω

φφ m

TY r

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≡Abundance of decay products (including DM)DM content: also needs to consider the DM annihilation for large Yφ

Moroi, Randall’99; Acharya, Kane, Watson’08,Randall; Kitano, Murayama, Ratz’08; Dutta, Leblond, Sinha’09; Allahverdi, Cicoli, Dutta, Sinha,’13

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Non-Thermal DM

DM arising from thermal equilibrium:

small unless <σannv> is small since Tr<Tf

Moduli decay into dark matter and the correct dark matter content can arise from the decay products:

1.

2. Abundance of Decay products (Yφ) is small enough, i.e., annihilation is not important any more Freeze-in.

3)(f

rth T

TΩ≈Ω

scmTT

vTT

vscm

r

f

f

r /)(103)(/10323.0 326326

−−

×=⇒

××=Ω σ

σ

Since Tr<Tf , Larger annihilation cross-section is needed to cut the large abundance (Yφ)

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Benefit of Non-Thermal DM

For Tr < Tf, larger annihilation cross-section is needed for

For Tr<< Tf, Yield is small ~10-10

DM will be produced without any need of annihilation[Note: For mDM~10 GeV, Yφ is needed to be ~10-10 to satisfy the

DM content]Outcome:

r

fth

fannfann TT

vv σσ =

DMDMr BRYY

mTY →=≡ φφ

φφ ;

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Large and small annihilation cross-section from models are okay We may not need any annihilation (Freeze-in)

Since other particles, abundance (for Tr<< Tf): 10-10

The Baryon and the DM abundance are correlated ~ 10-10+→ DMφ

Allahverdi, Dutta, Sinha’11

%27→Ω

DM and Baryon Abundance

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275

=ΩΩ

DM

b Baryon abundance: c

bbb

nmρ

=Ω

DM abundance: c

DMDMDM

nmρ

=Ω

ρc=critical densityn = number density

If mDM ~ few GeV nb ~ nDM (since mb=1 GeV)

Same number densities same originHeavy field decay to DM and generate Baryon abundance (without any annihilation cross-section uncertainty)Solves the coincidence problem

Predictive model has been constructedAllahverdi, Dutta, Mohapatra, Sinha, ‘13

Why baryon and DM abundances are similar?

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Baryogenesis from Moduli

βββ

ααααααβαβ λλ NNM

XXMXddXuNW cj

ciij

ciiextra 2

' +++=

: SM singlet; : Color triplet, hypercharge 4/3N XX , ±Baryogenesis f rom decays of or NXX ,

: can be the DM candidate with spin-independentcross-section: Allahverdi, Dutta, Mohapatra, Sinha’12

N~

εη φ Nbb

B BrYs

nn=

−≡

BrN : branching ratio of moduli decay to N

Assuming that N produces Baryon Asymmetry

ε : asymmetry factor in the N decay

ε<0.1, BrN ~ 10-2 -1 ηB = 9x10-11,1010~ 79 −− −τY

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Baryogenesis

From X decay

Typically, ε1,2 is O(10-2) for CP violating phase O(1) and λ~O(1)

Baryogenesis from Moduliββ

βααααααβαβ λλ NN

MXXMXddXuNW c

jciij

ciiextra 2

' +++=

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Non-Thermal mSUGRA/CMSSM

CMSSM/mSUGRA parameters: m0, m1/2, A0, tanβ, sign of µ + TR We consider the case with large <σv>ann

This scenario can be realized in the context of LVS

Aparicio, Cicoli, Dutta, Muia, Quevedo’16

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DM from Early Matter domination

If the dark matter kinetically decouples prior to reheating enhances small-scale perturbations which significantly increase the

abundance of microhalos

The boost to the annihilation rate from themicrohalos is sufficient to be observed at FERMI

Thermal DM abundance from early matter domination (moduli)

DM candidate can be Neutralino

Small <σannv> is allowed by the DM content

Kamionkowski and M. S. Turner,’90;Giudice, Kolb, Riotto,’01; Gelmini,Gondolo’06

Erickcek’15

Erickcek, Sigurdson,’11

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Non-Standard Cosmology

A new H (≡ 𝒂𝒂𝒂

) appears (not same as the standard cosmology)

The Boltzmann equation also gets modified

Modify <σannv> to satisfy the DM content

Catena, Fornengo, Masiero, Pietroni, Rosati’04Meehan, Whittingham, ‘15

Bekenstein’93Koivisto, Wills, Zavala, ‘13

S

Correlate DM and DE

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Changing H before BBN

Dutta, Jiminez, Zavala, ‘16

𝝋𝝋 = 𝟎𝟎.𝟐𝟐,𝝋𝝋′ = −𝟏𝟏.𝟏𝟏𝟏𝟏𝟎𝟎Initial conditions:

Y(x)

annihilation

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Larger and smaller <σv>

annhilationreannihilation

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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

DM annihilation from galaxy, extragalactic sources

Annihilation into photons: Fermi, CTA, HAWC

Annihilation into neutrinos: IceCube

>< vannσ