Leptogenesis and CP violation of Neutrino Sectors

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Leptogenesis and CP violationof Neutrino Sectors

• Takuya Morozumi
• Hiroshima university
• ICFP 2005 at ChungLi Oct.6th

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Leptogenesis / Seesaw/ CPV

• (1) Leptogenesis (Fukugita, Yanagida) is a
  scenario which may explain Baryon number of
  universe through Lepton number generation.
• (2) In the scenario, heavy Majorana neutrinos
  with Mass typically heavier than 1 TeV to 1012
  GeV introduced.

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Thermal History of Leptogenesis Buchmuller,
Plumacher, Luty

• Heavy Majorana neutrino (in seesaw) decays
• CP violation
• Lepton number transformed into Baryon number
• provided by non-conservation of BL in SU(2)
  ?
• U(1) model

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CP violation of Leptogenesisand low energy CP
observables

• Natural question is whether CPV phase of MNS
  matrix related to CPV of leptogenesis.

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Production Mechanism of Lepton Number
F
F
Tree
Vertex
L
L
F
L
Self-energy
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CP Mirror
L
F
Tree
Vertex
L
Self-energy
F
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Seesaw Model
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Structure of
3?N matrix
3N-3 CP violating phases
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CP asymmetry related to leptogenesis
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e-Leptogenesis Model and ?-less double beta
decay

• Lepton number asymmetry from Lightest (N1) decays
  dominated by Electron Family LLe

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F

F
Le
Le
n
n
P
P
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Indication on seesaw parameters
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CP violation of leptogenesis andneutrino
oscillation

• Connection is not so manifest.
• Neutrino oscillation L conserved processes
• Leptogenesis L violating processes

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In seesaw , neutrino-neutrinotransition involves
neutrino-antineutrinotransitions

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CP violationof Neutrino oscillationin seesaw
N1
N1
N2 N2
N1
N1
N2
N2
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N1
N1
N2 N2
N1
N1
N2
N2
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Previous example corresponds toe-Leptogenesis
scenario LLe

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Signatutre of seesaw at low energy
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QLFV and LFV in seesaw


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How large

• In conventional seesaw
• The ratio is quite small
• or M ltlt Mw and E is small.
• For n1 eV,

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Suppression of L violation andenhancement of
(Q)LFV can coexist. Pilaftis
Cancellation of L violating int.
No cancellation for LFV
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Concrete model and predictions
Fujihara, Kang, Kim,
Kimura, T.M.
Spectrum
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Correllation of QLFV and LFV mode s13 0.001
0.05 0.1
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Previous figures are obtained
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summary

• 1. If seesaw is a right theory, leptogenesis
  phases
• certainly have impact on CP violation of
  neutrino
• oscillation (d) and neutrinoless double beta
  decay(a). However, non-zero (or zero CP
  violation)of neutrino oscillation does not imply
  leptogenesis phase is present (or absent).
• 2. Neutrinoless doble beta decay measurement does
  not Imply presence of CP violation. However, if
  we may not fit mee without majorana phase (a),
  this may be related to leptogenesis phase.
• 3. (Q)LFV processes (no susy effect) can be
  enhanced in a class of model. Direct evidence of
  Seesaw may be experimentally explored.