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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
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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