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Leptogenesis and Triplet Seesaw. Eung Jin Chun KIAS. Based on hep-ph/0609259 in collaboration with S. Scopel. TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: A. Matter-Antimatter asymmetry of the universe. No antimatter around us. Observation: - PowerPoint PPT Presentation
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Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Leptogenesis and Triplet Seesaw
Eung Jin ChunKIAS
Based on hep-ph/0609259 in collaboration with S. Scopel
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Matter-Antimatter asymmetry of the universe
• No antimatter around us.• Observation: • Asymmetrical initial condition after bigbang?• Generation of the asymmetry starting from matter
-antimatter symmetrical universe: “baryogenesis”• Sakharov condition: (1967) B or L violation
C and CP violation
Out of equilibrium
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Electroweak Spharelon Processes
B & L are conserved classically in SM.
Invariant under 6-3=3 U(1) symmetries
SU(3)c £ SU(2)L £ U(1)Y
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Electroweak Spharelon Processes
B+L is anomalous under SU(2)L
and thus broken by quantum effect.Efficient spharelon transitions at T>MW.
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Equilibrium distributions of charge asymmetries
• Equilibirum number densities:
• For T À m, • For T ¿ m• Charge asymmetry in X:
FD
BE
for FD/BE
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Equilibrium distributions of charge asymmetries
• B & L asymmetry:
• Spharelon erasure: B = L=3
• Gauge charge neutrality:
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Equilibrium distributions of charge asymmetries
• All gauge and Yukawas in equilibrium:
• Initial asymmety in transfers to B/L:
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Leptogenesis and Neutrino masses
Neutrino masses observed: Majorana nature of the small mass from
L violation: Requires new particles as the source of L violatio
n at high scale. Heavy particle decay falls into out-of-equilibrium f
or T<MX prohibiting inverse decays. Provided a nontrivial CP phase in the decay, a co
smological L asymmetry may arise as required by the observation.
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Leptogenesis in Singlet Seesaw Seesaw through singlet RHNs with heavy Majorana masses:
RHN decay produces CP/L asymmetry: tree+loop interference with CP phase in Yukawas
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Leptogenesis in Singlet Seesaw
CP asymmetry in RHN decay:
for M2,3 À M1
with eff·1
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Leptogenesis in Singlet Seesaw
Boltzmann equation:Inverse decay effective for KÀ1
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Leptogenesis in Singlet Seesaw
Approximate solution:Damping factor by inverse decay:
Cosmological lepton asymmetry:
ID=H
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Leptogenesis in Triplet Seesaw
• Supersymmetric Higgs Triplets with Y=1,-1
• Neutrino mass via seesaw in VEV:
• Triplet decays produce L asymmetry:
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Leptogenesis in Triplet Seesaw
• Boltzmann Equations
Gauge annihilation: * WW :
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Leptogenesis in Triplet Seesaw
• Decay vs. Annihilation:
• Leptogenesis Phenomenology with 5 independent parameters:
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Amount of CP violation required by observation in SM with only two channles: X LL, HH
Efficience increases far away from BL=BH=1/2
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Role of the third channel X H1 H1 in SUSY
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Lepton asymmetry generation with vanishing L
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Features with slow & fast for slow (Ki ¿ 1) & fast (Ki À 1) channel.slow=1: Efficiency reaches maximum.Inverse decays in the slow channel freeze out early, and annihilations determine the triplet density up to quite large mass M.The final asymmetry is a growing function of K parameter and is insensitive to fast. Even L=fast=0 can lead to efficient leptogenesis.
slow and one slow channel: The final lepton asymmetry is suppressed.Inverse decays freeze out late (zf» ln K À1), and decay is typically dominant over annihilation except for very small M. As a consequence, the efficiency scales as 1/(zf K) with K À1.
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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slow<1 and two slow channels: The slow channel with large i drives leptogenesis with a good efficienc
y. The system is practically with two decay channels as in SM. If slow=L,2, the phenomenology is different from SM case because K no
w is much bigger, reducing the efficiency at high masses and improving it at lower ones.
Features with slow & fast for
slow (Ki ¿ 1) & fast (Ki À 1) channel.
Nov.9, 2006, SNU Leptogenesis & Triplet Seesaw
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Conclusion
• Matter-Antimatter asymmetry of the Universe requires New Physics: B/L violation, new CP phase.
• It may have the same origin as the neutrino mass generation.
• Revelation of such connection in the future experiments?
• Successful leptogenesis can be attained in a wide range of scenarios in supersymmetric triplet seesaw model.