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B. Dutta
Texas A&M University
Phys.Rev.Lett.99:261301, 2007; To appear
Inflation, Dark Matter and Neutrino Masses
Collaborators: Rouzbeh Allahverdi, Anupam Mazumdar
ICHEP ‘08
Inflation and Dark Matter: Needs new physics
What is this well motivated model particle physicsmodel?
Neutrino masses are small and require new physics: Can they be tied to this model?
How can we test this model? Where?
LHC, dark matter detection …
How economically can we achieve all these?
Introduction
We consider supersymmetry
Dark Matter Candidate ~ (weak scale)
Inflaton Mass ~ (weak scale)
Sneutrino (spin 0) is the candidate
Scalar Inflaton field contains the DM particleSneutrino
Left Sneutrinos are ruled out as dark matter candidates
We will consider New Sneutrinos
Supersymmetry Framework
We consider simple extension: SU(3) x SU(2)L x U(1)Y x U(1)B-L
B-L sneutrino can be the dark matter candidate
U(1)B-L gets broken at a TeV or so
We have an extra Z’ and 3 more neutralinos
This is a minimal extension of the SM
Model
The model provides Dirac mass for neutrinos
The inflaton is composed of : Higgs field, Slepton and Sneutrino
The corresponding flat direction : NHuL (W h NHuL)
The mass of the flat direction is described in terms of the sparticle masses O(weak scale)
The mass of the inflaton, ~ O(weak scale)
Inflaton
Note: DM candidate sneutrino is a part of the inflaton
3
~~LHN u
where,
Flat direction and MSSM [Allahverdi, Enqvist, Kusenko, Mazumdar…]
The potential along the flat direction :
h is the Yukawa coupling
For A = 4 m
We get V’(0)=0 V’’(0)=0 but V’’’(0) 0
342
22
||36
||12
||2
|)(| AhhmV f
V()=V(0)+1/3!V’’’(0)(-0)3+…
Potential for inflation
V
In order to fit the CMBR result we need h~10-12
We need this small coupling to explain the neutrino mass
We have Dirac neutrinos
=h<Hu> M~O(0.1) eV
Tiny neutrino mass arises when we explain inflation in this model
Small Neutrino Mass
Inflaton is related to the neutrino mass:
H ~ 1.91 x 10-5
Amplitude of Perturbations: H ~ f(m,m,0)
Inflaton vs neutrino masses
Phys.Rev.Lett.99:261301, 2007
Inflaton and sparticle masses are correlated
We use SUGRA boundary condition
=1200 GeVmg~
1640 GeV
730 GeV
m=0.3 eV
Each line: Left end m0=0; Right end : M(sneutrino)=M(neutralino)
Inflaton and other SUSY masses
Dark matter content is explained: Sneutrino is the LSP
Sneutrino component of inflaton has never decayed
-prime: t –channel, Z-prime: s-channelZ~
Dark Matter Content
Phys.Rev.Lett.99:261301, 2007
Direct Detection of dark matter
LHC: Signal is similar as in the standard scenario with neutralino LSP
If we can identify the spin of dark matter particleit is possible extract this model
Work in progress…
N~ interacts with quark via Z’ exchange
Typical cross section : 2 x10-8 pb for Z’ mass ~ 2 TeV
Collider Signal:
Signal
However, sneutrino has spin 0
Conclusion
It is possible to explain Inflation and dark matter in the context of particle physics model
We need to extend the MSSM by an extra U(1) symmetry
Sneutrino is the dark matter candidate which is part of the flat direction for inflation
Dark Matter content can be satisfied
Direct detection experiment can observe it
One can distinguish this scenario at the LHC if the spin of the missing particle can be measured