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Testing Seesaw at LHC 郑亚娟
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Outline Mini-review of neutrino physics
LHC signatures of Seesaw mechanism
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Introduction Part I Beta decay
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Neutral, spin ½, mass less than 1% of proton mass
Neutrino
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Neutral, spin ½, less than 1% of proton mass
Neutrino
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True picture: An electron antineutrino is emitted from beta decay
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Detection
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using neutrinos from a fission reactor
A decision in 1952: using neutrinos from a fission reactor A double signature (two flashes of light separated by a few )
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Lederman, Schwartz & Steinberger 1962 Cowan & Reins 1956 39 years
BNL Lederman, Schwartz & Steinberger 1962 Cowan & Reins 1956 39 years 26 years 1995 1988 : Fermi Lab, 2000
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Neutrino puzzles Solar neutrino Detected neutrino
1/3 Standard Solar Model 1968, Raymond Davis made the first observation of solar neutrino shortfall at Homestake mine Confirmed by Kamiokande, GALLEX, SAGE and SNO(2001) data R. Davis 2002
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Atmospheric neutrino Expected Detected
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Two flavor oscillation
For simplicity, we consider two flavor neutrino mixing and oscillation
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The oscillation probability for an appearance neutrino experiment:
The conversion and survival probability in realistic units: Due to the smallness of (1,3) mixing, both solar & atmospheric neutrino oscillations are roughly the 2-flavor oscillation.
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Flavor Mixing Flavor eigenstates Cabibbo-Kobayashi- Maskawa (CKM)
Weak interaction eigenstates Mass eigenstates Flavor eigenstates Pontecorvo-Maki-Nakagawa-Sakata (PMNS)
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Experimental bounds Two kinds of hierarchy ( normal & inverted) Normal
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Mass Generation SM + right-handed neutrino Unnatural
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Radiative mechanisms (S. Weinberg PRD1962, A. Zee PLB1980)
Texture zeros (H. Fritzsch PLB1977, S. Weinberg1977) Family symmetries (C. Froggat & H. Nielsen NPB1979) Seesaw mechanisms (P. Minkowski PLB1977) Extra dimensions (K. Dienes, E.Dudas & T.Gherghetta NPB1999)
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Seesaw Mechanisms Type-I : (SM +at least 2 RH Majorana neutrinos )
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Type-II : (SM +1 Higgs triplet )
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Type-III: (SM +3 fermion triplet )
Hybrid seesaws: type-(I+II), type-(I+III) …
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Part II Type-(I+II) Seesaw SM + 2 right-handed Majorana neutrinos Higgs triplet SSB Diagnolization Seesaw formula
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Neutrino Mixing Tri-bimaximal mixing pattern After diagnolization
Harrison et al, 02; Z. Z. Xing, 02; X. G. He & A. Zee, 03 Parameterization 3×3 unitary matrix Z. Z.Xing, 08 Nearly identity matrix with
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Conventional: Testable: Pilaftsis, 92;Kersten et al, 07
W. Chao, Z. G. Si, Z. Z.Xing, S. Zhou 08; W. Chao, S. Luo, Z. Z. Xing, S. Zhou 07 Flavor symmetry X. G. He, Y. Y. Keum & R. R.Volkas 06 a. Triplet Higgs observable b. Heavy Majorana neutrinos testable c. Neutrinos masses stable
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Collider Signatures T. Han & B. Zhang, 06; A. Atre, T. Han, S. Pascoli & B. Zhang,09
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Define:
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guarantees a peak around the mass of
>114GeV CDF Collaboration, 08
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Thanks for your attention!
Summary Long Long Ago Far Far Away Thanks for your attention!
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