Models of Neutrino Mass

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Models of Neutrino Mass
G.G.Ross, IPPP December 2005
Origin of mass and mass hierarchy
What do we learn from the mixing angles?
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Origin of Neutrino masses
Dirac or Majorana?
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Origin of Neutrino masses
Dirac or Majorana?
Weinberg 1979
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Origin of Neutrino masses
Dirac or Majorana?
Weinberg 1979
Minkowski mechanism
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Origin of Neutrino masses
Dirac or Majorana?
Weinberg 1979
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Dirac or Majorana?
New space dimensions
Arkani Hamed, Dimopoulos, March
Russell Dienes,Farragi


Flux spreading
In 4D small Dirac masses can arise through higher
dimension operators
Abel, Dedes, Tamvakis
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Neutrino mass and dark energy
Symmetry needed to keep it light
Quintessence field
CP violating field of neutrino mass matrix?
Barbieri, Hall, Oliver, Strumia
Mass varying neutrinos
Fardon, Nelson, Weiner
energy in A
At finite density
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Hierarchy
dimension of operator
order of radiative corrections
Structure
Can get normal, inverted or degenerate structures
(NB Radiative corrections can split precise
degeneracies unless protected by symmetry)
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Unravelling the origin of mass..
Many possibilities, many parameters
difficult (impossible) unless we are lucky!
Small in quark sector, large in lepton sector?
Mixing
Non Abelian Structure?
Bi-Tri Maximal Mixing
Harrison, Perkins, Scott ansatz
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Tri-Bi-Maximal mixing
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Discrete non Abelian family symmetry
Bi-maximal
But what about the charged lepton sector
Need complete theory
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Two ingredients
See-saw with sequential domination
SRHD King
small
(Discrete) Non-Abelian family symmetry
King, GGR, Varzielas
Vacuum alignment
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Vacuum alignment
Altarelli,Feruglio
King,GGR,Varzielas
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Summary
Origin of mass and mass hierarchy
- Many possibilities for both Majorana and Dirac
masses
Heavy see-saw, light see-saw, bare Dirac,
radiative generation, radiative running, running
massesdark energy
- All patterns of mass possible
normal, inverted, degenerate
What do we learn from the mixing angles?
-Hints at an underlying (spontaneously broken)
family symmetry?
SO(10)XSU(3)? Unified theory of quark,
charged lepton and neutrino masses
with related textures
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I de Medeiros, GGR King, Vives, Velasco Sevilla
Spontaneous symmetry breaking
c.f. Georgi-Jarskog
Common texture zero
only terms allowed by G
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Summary
Origin of mass and mass hierarchy
- Many possibilities for both Majorana and Dirac
masses
Heavy see-saw, light see-saw, bare Dirac,
radiative generation, radiative running, running
massesdark energy
- All patterns of mass possible
normal, inverted, degenerate
What do we learn from the mixing angles?
-Hints at an underlying (spontaneously broken)
family symmetry?
SO(10)XSU(3)? Unified theory of quark,
charged lepton and neutrino masses
with related textures
- A discrete non-Abelian subgroup can give vacuum
alignment needed for bi-tri-maximal mixing