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CP Violation and Flavor Mixing Makoto Kobayashi KEK and JSPS Plan CP Violation and Flavor Mixing Makoto Kobayashi KEK and JSPS Plan 1. Introduction to the Standard Model 2. Sakata and His Group 3. The CP Paper with Maskawa 4. Experimental Verification at B-factories 5. Lepton Flavor Mixing Introduction to the Standard Model u d u Electron p Proton（p） n Nucleus d d u Atom Neutron（n） Introduction to the Standard Model Fundamental Particles u c t Quark d s b e μτ Lepton νe νμ ντ Fundamental Interactions • Strong Interaction QCD • Electro‐Magnetic Interaction • Weak Interaction Weinberg‐Salam‐Glashow Theory Introduction to the Standard Model Established in 1970’s ・ Development of gauge theory 1971 ‘t Hooft Electro‐Magnetic Interaction Strong Interaction Weak Interaction ・ Discoveries of new flavors u c t 1964 Gell‐Mann quark model d s b u, d, s e μτ 1973 Kobayashi Maskawa νe νμ ντ Six‐Quark Model After 1970 Sakata and His Group 1947∼ Discovery of Strange Particles Hadron : strongly interacting particle p n π±0 Λ ΛΣΞ±0 KK± 0 Λ lairmoeM kata Saf osyteruoC Archival Library Strange Particles Shoichi Sakata 1911-1970 1956 Sakata Sakata Model All the hadrons are composite states of p,, n Λ : Fundamental Triplet Sakata and His Group Weak Interaction in the Sakata Model - decayβ n→ p + − e ν + strange paticle→Λ p + e− ν + p ν n Λ e μ 1959 Gamba, Marshak, Okubo B‐L Symmetry 1960 Maki, Nakagawa, Ohnuki, Sakata Nagoya Modelp : = B+ν ,, n = B+ e Λ+ =μ B Sakata and His Group 1962 Discovery of Two Neutrinos ν e ν μ Lepton Flavor Mixing e μ MNS Matrix 1962 Maki, Nakagawa, Sakata + + + + p = B ν1 , n = B e , Λ = B μ , p'= B ν 2 ν1 = cosθ ν e + sinθ ν μ ν 2 = −sinθ ν e + cosθ ν μ Neutrino Oscillation 4th Fundametal Particle (GIM scheme) 1962 Katayama, Matumoto, Tanaka, Yamada Sakata and His Group Cosmic Ray Events 1971 Niu et al. Evidence for the 4th element? Some Japanese groups began to investigate the four-quark model Emulsion Technique • Applied to accelerator exp. • Life time measurement of the new flavors CP Paper with Maskawa 1971 ‘t Hooft : Renormalization of Non-Abelian gauge theory Renormalizable Electro-Weak Theory (Weinberg-Salam-Glashow ) CP Violation 1964 Cronin et al. 1973 Kobayashi, Maskawa K L → ππ Essential difference How to accommodate CP violation between particles and anti-particles What we found • Not possible in four-quark models • Existence of unknown particles • A possible candidate is six-quark model CP Paper with Maskawa Flavor Mixngi Mismatch between gauge symmetry and particle spectra ⎛u ⎞ ⎛c ⎞ ⎛d′⎞ VV⎛ ⎞ ⎛d ⎞ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ = ⎜ ud us⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ′ ⎟ ⎜ ⎟ ⎜ ⎟ ⎝d′⎠ ⎝ s′⎠ ⎝ s ⎠ VV⎝ cd cs⎠ ⎝ s ⎠ CP Violation Complex elements not removable by the phase convention ⎛e −iδu 0 ⎞VV⎛ ⎞⎛e iδd 0 ⎞ cos⎛ θ− sin θ⎞ ⎜ ⎟⎜ ud us⎟⎜ ⎟ = ⎜ ⎟ ⎜ −iδc ⎟⎜ ⎟⎜ iδ s ⎟ ⎜ ⎟ ⎝ 0 e ⎠VV⎝ cd cs⎠⎝ 0 e ⎠ sin⎝ θ cos θ⎠ CP Paper with Maskawa 6-Quark Model ⎛d′⎞VVV⎛ ⎞ ⎛d ⎞ ⎛u ⎞ ⎛c ⎞ ⎛t ⎞ ⎜ ⎟ ud⎜ us⎟ ub⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ′ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ s ⎟VVV= ⎜cd cs⎟ cb⎜ s ⎟ ⎝d′⎠ ⎝ s′⎠ ⎝b′⎠ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎝b′ ⎠ VVV⎝td ts⎠ tb⎝b ⎠ VVV ⎛ 1− λ2 2 λA λ3 ( ρ− i)⎞ η ud⎛ us⎞ ub ⎜ ⎟ VVV⎜ ⎟ ≈ − λ 1− λ2 2 Aλ2 ⎜cd cs⎟ cb ⎜ ⎟ VVV⎜ ⎟ ⎜ 3 2 ⎟ ⎝td ts⎠ tb λ⎝ A −()1 ρ −i η −A λ 1 ⎠ • An imaginary number parameter violates CP CP Paper with Maskawa • 1974 Discovery of J/ψ c-quark • 1975 Discovery of τ -lepton 1975 S. Pakvasa, H. Sugawara 1976 J.R Ellis, M-K Gaillard, D. Nanopoulos • 1977 Discovery of Υ b-quark • 1995 Discovery of t-quark Large CP violation in the B-meson system 1980 Carter, Sanda Bd : b d Bd d: b 1981 Bigi, Sanda B : B-Factory u b u Bu:u b B-Mesons E(e−)=8GeV, E(e−)=9GeV, E(e+)=3.5GeV Feature E(e+)=3.1GeV Finite angle beam crossing Zero angle beam crossing 1994 1993 May 1999 – May 1999 – still running Apr. 2008 L = 1.7×1034/cm2/s Friendly competition of two peak experiments over a decade 34 2 Lpeak = 1.2×10 /cm /s PeP-II BaBar Belle: 14 countries, 59 institutes, about 400 researchers Experimental Verification at B-Factories Experimental Verification at B-Factories Present Status of CP Violation B-factory results show that quark mixing is the dominant source of CP violation B-factory results allow room for additional source from new physics Matter dominance of the Universe seems requiring new source of CP violation Lepton Flavor Mixing Discovery of neutrino oscillation at Super-Kamiokande using atmospheric neutrinos Atmospheric Neutrino Multi-GeV μ-like + PC Super-K 1996～ θ Earth ν C.R. Courtesy of KEK Yoji Totsuka 1942-2008 J.Raaf, Talk at Neutrino 2008 Lepton Flavor Mixing K2K experiment KamLAND experiment νμ : KEK-PS νe： reactor fit_out.0x03.cmb.free.1.shape ] 18 Entries 58 GeV [ 16 1R-μ spectrum 14 events/0.25 12 No oscillation 10 Oscillation 8 6 Number of events 4 2 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 [GeV] 1 234Eνrec νμ disapearance νe disapearance Lepton Flavor Mixing T2K experiment νμ created at JPARC Super-K Aiming to discover νe appearance.
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