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Unified TeV Scale Picture of Dark Matter and Baryogenesis. R. N. Mohapatra University of Maryland Neutrino Telescope 2007, Venice (K. S. Babu, S. Nasri and R. N. M., hep-ph/0612357). Current Prevalent Thinking. - PowerPoint PPT Presentation
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March 2005Theme Group 2
Unified TeV Scale Picture of Dark Unified TeV Scale Picture of Dark Matter and BaryogenesisMatter and Baryogenesis
R. N. MohapatraUniversity of Maryland
Neutrino Telescope 2007, Venice
(K. S. Babu, S. Nasri and R. N. M., hep-ph/0612357)
March 2005Theme Group 2
Current Prevalent ThinkingCurrent Prevalent Thinking• Dark matter is either LSP of Supersymmetry
or lightest Kaluza-Klein Mode in models with extra Dimensions with R~TeV^-1 or perhaps the axion.
• Origin of Matter comes from different physics i.e. from Right handed neutrino decay in Seesaw models for neutrinos involving sphalerons.
• Unrelated physics
March 2005Theme Group 2
Dark Matter issues in MSSMDark Matter issues in MSSM
• Getting the dark matter to fit into MSSM requires fine tuning:
(i) Either Bino-Higgsino mixing must be fine tuned to get the right relic density
Or (ii) Co-annihilation needed where stau and LSP nearly degenerate (within 20 GeV): requires adjustment of m^2_0.
March 2005Theme Group 2
Co-annihilation-DetailsCo-annihilation-Details
•LSP-Stau fine tuning:
GeVM 20
March 2005Theme Group 2
Dark Matter Constraints on MSSMDark Matter Constraints on MSSM
129.094. 2 hCDM
March 2005Theme Group 2
Constraints at Higher tan betaConstraints at Higher tan beta
March 2005Theme Group 2
Perhaps Gravitino Dark matterPerhaps Gravitino Dark matter• Feng Takayama, Rajaraman;,
• LSP Gravitino : Another alternative.
Escapes direct detection.
Similar constraints
on MSSM parameter
space
Ellis, Olive, Santoso, Spanos
March 2005Theme Group 2
Yet SUSY has its own appealYet SUSY has its own appeal• It stabilizes the weak scale against
radiative corrections;• It leads to unification of gauge
couplings.• So is there an extension of MSSM that
preserves these good features, broadens the parameter space of MSSM and gives a unified picture of dark matter and origin of matter and neutrino masses?
March 2005Theme Group 2
Neutrino mass extension of MSSMNeutrino mass extension of MSSM• Add three right handed neutrinos with heavy
Majorana masses:• New superpotential:
Leads to seesaw formula for neutrino masses:
N-decay via leptogenesis leads to baryon asymmetry.
MNNNLHhWW uMSSM
R
D
M
mM
2
March 2005Theme Group 2
Two points about this model:Two points about this model:
• Neutrino Observations do not require three RH neutrinos- two are enough. (the so-called 3X2 seesaw)
• SUSY seesaw models for leptogenesis have some problems !!
March 2005Theme Group 2
Issues with leptogenesis modelsIssues with leptogenesis models
• In typical scenarios, often the lightest RH neutrino masses are higher than the reheat temperature after inflation coming from gravitino abundance- posing a problem.
(Davidson, Ibarra have a lower bound on MN of GeV ;
also true in many interesting SO(10) models.
The upper bound on T-reheat for generic TeV scale gravitinos
is < GeV ; Kohri, Mori,Yotsuyanagi )
910
710
March 2005Theme Group 2
Upper bound on T-reheat (Kohri et al paper)Upper bound on T-reheat (Kohri et al paper)
March 2005Theme Group 2
New ModelNew Model
• Could it be that only two of the RH neutrinos are heavy and the third one is very light (i.e. TeV scale )
• We show that• (i) such a model can naturally arise from a
simple symmetry;• (ii) In this case, one can have a unified TeV
scale model for both baryogenesis, neutrino masses and dark matter.
March 2005Theme Group 2
New proposal: XMSSMNew proposal: XMSSM• 3x2 seesaw model with the third RH neutrino
in the TeV scale and decoupled from the neutrino sector:
• Plus a pair of color triplets: and with couplings:
Impose R-parity symmetry as in MSSM.
This simple extension provides a remarkably natural model for dark matter, neutrinos and baryogenesis and has testable predictions !!
X X
XddXNuW lc
kc
klic
i NNM N XXM X
March 2005Theme Group 2
Grand unification of this modelGrand unification of this model• If and belong to full SU(5) multiplets
10 and 10-bar , Coupling unification is not affected.
• Only the value of then final value of the GUT coupling changes. - Couplings motivated by SO(10) GUT: , part of 120 Higgs and 16 .16. 120 coupling
leads to our interactions. - Discrete symmetry guarantees the third RH
N decoupling naturally. (see later)
X X
X X
March 2005Theme Group 2
Baryogenesis and Dark MatterBaryogenesis and Dark Matter
• Mass ordering among particles:
,
MSUGRA boundary condition implies that
Where are the real and imaginary parts of .
is stable and is the dark matter candidate. N unstable and gives
TeVM XX , NNsleptonssquarks MM ~,, GeV100
21~~ ,NNN
MMM 2,1
~N N
~
1
~N
nnB /
March 2005Theme Group 2
Scalar mass runnning to weak scale MSSMScalar mass runnning to weak scale MSSM
N~
Assume scalar masses same at high scale.
March 2005Theme Group 2
DecayDecay mode of N-fermion mode of N-fermion
• X-exchange gives a decay
+ anti-quark modeccc dduN
N cu
X cd
cd
2
)(
X
kljjklN
MG
March 2005Theme Group 2
Post Sphaleron BaryogenesisPost Sphaleron Baryogenesis
• Babu, R. N. M., Nasri, Phys Rev. Lett. 97, 131301 (2006)
• Out of equilibrium condition (one of three Sakharov conditions)
satisfied at:
For , N goes out of equilibrium below its mass and is ready to generate baryons via its CP and baryon violating decay.
PldduN M
Tg
ccc
2
222
53
)11
()(19221
1)(
21 XX MMMTrN
42/12 10])}[({ Tri
March 2005Theme Group 2
Baryogenesis DiagramsBaryogenesis Diagrams• N decay to 3 quarks and anti-quarks are different
due to CKM CP violation and interference between tree and one loop diagrams: (no sphalerons needed)
+
cu
cd
cd
March 2005Theme Group 2
Estimate ofEstimate of B
||
sin
4 222
221232
W
ubbcB
M
Vmm
Dominant contribution is from W-Dominant contribution is from W-exchange and is:exchange and is:
Gives:Gives:
Right order.Right order.
222
23218
||103
B
March 2005Theme Group 2
As Scalar dark matterAs Scalar dark matter
1
~N 1
~N
1
~N
Relic density:Relic density:Annihilation channelAnnihilation channel
Cross section:Cross section:
For reasonable choice of parameters, cross For reasonable choice of parameters, cross section is of order of a 0.1 pb and gives the section is of order of a 0.1 pb and gives the right relic density.right relic density.
ccuu
4
22 ||)(
8
1
XM
pv
March 2005Theme Group 2
Releases the SUSY parameter spaceReleases the SUSY parameter space
not
dconstraine
not In NXMSSMIn NXMSSMnot
///////\\\\\\\\\\/////
March 2005Theme Group 2
Direct detection of dark matterDirect detection of dark matter
2
4
241
~
641
A
ZA
M
m
X
p
pN
Cross section about 10^(- 45) cm^2-Cross section about 10^(- 45) cm^2-In the observable range.In the observable range.
March 2005Theme Group 2
A crucial experimental testA crucial experimental test
• N-N-bar oscillation: Diagram involves Majorana N exchange
• Effective strength:
• Will lead to N-N-bar osc via the s-content in neutron.• Transition time expected to be around 10^8 sec.
NXB MM
G4
1212
cccccc sdusduO
March 2005Theme Group 2
Present expt situation in N-N-bar Osc.Present expt situation in N-N-bar Osc.
Range accessible to current reactor fluxes:
Present limit:ILL experiment: Baldoceolin et al. (1994)
New proposal by Y. Kamyshkov et al for an expt at
DUSEL GOAL:
Figure of merit ~
.sec108 nn
.sec1010 1110 2
nn
tFlux
.sec1010~ 118 nn
March 2005Theme Group 2
Scheme of N-Nbar search experiment at DUSEL
Dedicated small-power TRIGA research reactor with cold neutron moderator vn ~ 1000 m/s
Vertical shaft ~1000 m deep with diameter ~ 6 m at DUSEL
Large vacuum tube, focusing reflector, Earth magnetic field compensation system
Detector (similar to ILL N-Nbar detector) at the bottom of the shaft (no new technologies)
March 2005Theme Group 2
Tests at LHC--Tests at LHC--New signaturesNew signatures
(i) Monojet + missing energy signals from X-production in pp collision.
(Missing energy is N)
(ii) 4 jets + missing energy from:
NqXqq
qqqq~~
c c
Nqq ccNqq cc N
~N~
March 2005Theme Group 2
Symmetry giving this modelSymmetry giving this model
Consider Seesaw model for neutrinos invariant under a that exchanges only
RH neutrino field decouples
from seesaw formula which now becomes a 3x2 seesaw involving and .
Our singlet field then is N= ;
N mass can be chosen in the 100 GeV range without affecting neutrino masses or other low energy observations !!
,2RZ NN
)(2
1 NNN
eN )(2
1 NNN
)(2
1 NNN
March 2005Theme Group 2
Tests in neutrino mixingsTests in neutrino mixings
• 3X2 seesaw with 2 RH neutrinos:
• For normal hierarchy, it necessarily predicts nonzero and of order
; hence testable.
- Inverted hierarchy if is zero.
13
solar
atm
m
m2
2
13
March 2005Theme Group 2
ConclusionConclusion• A simple extension of MSSM that gives
a unified TeV picture of dark matter and baryogenesis. Less fine tuned than MSSM. Embeddable into a seesaw model for neutrinos.
• Opens up MSSM parameter space.• SUSY phenomenology (e.g. LHC signal)
very different from MSSM.• Crucial test is Neutron-anti-neutron osc
time in the observable range.