CP Violation and Flavor Mixing Makoto Kobayashi KEK and JSPS Plan - PowerPoint PPT Presentation

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 u c c t t Quark s s b b d d e μ τ Lepton ν e ν μ ν τ Fundamental Interactions • Strong Interaction QCD • Electro ‐ Magnetic Interaction Weinberg ‐ Salam ‐ Glashow Theory • Weak Interaction

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 s quark model d b u, d, s e μ τ 1973 Kobayashi Maskawa ν e ν μ ν τ Six ‐ Quark Model After 1970

Sakata and His Group 1947 ∼ Discovery of Strange Particles Hadron : strongly interacting particle ± π Λ 0 p n ± K ± Λ Σ Ξ Λ 0 0 K Courtesy of Sakata Memorial Archival Library Strange Particles Shoichi Sakata 1911-1970 1956 Sakata Sakata Model All the hadrons are composite states of Λ , , p n : Fundamental Triplet

Sakata and His Group Weak Interaction in the Sakata Model − β → + + ν - decay n p e − Λ → + + ν strange paticle p e ν p μ Λ e n 1959 Gamba, Marshak, Okubo B ‐ L Symmetry 1960 Maki, Nakagawa, Ohnuki, Sakata + + + = ν = Λ = μ p B , n B e , B Nagoya Model :

Sakata and His Group 1962 Discovery of Two Neutrinos ν e ν μ Lepton Flavor Mixing μ e MNS Matrix 1962 Maki, Nakagawa, Sakata = + ν = + Λ = + μ = + ν p B , n B e , B , p ' B 1 2 ν = θ ν + θ ν cos sin μ 1 e ν = − θ ν + θ ν sin cos μ 2 e Neutrino Oscillation 4 th Fundametal Particle (GIM scheme) 1962 Katayama, Matumoto, Tanaka, Yamada

Sakata and His Group Cosmic Ray Events 1971 Niu et al. Evidence for the 4 th 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. → ππ K 1973 Kobayashi, Maskawa L 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 Mixing Mismatch between gauge symmetry and particle spectra ⎛ ⎞ ⎛ ′ ⎞ ⎛ ⎞ ⎛ ⎞ ⎛ ⎞ u c d V V d ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ = ⎜ ⎟ ud us ⎜ ⎜ ⎟ ⎜ ⎟ ⎟ ⎜ ⎟ ⎜ ⎟ ′ ′ ′ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ s V V s d s cd cs CP Violation Complex elements not removable by the phase convention ⎛ ⎞ ⎛ ⎞ θ − θ − δ ⎛ ⎞ δ ⎛ ⎞ i i V V cos sin e 0 e 0 u d ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ = ⎜ ⎟ ud us ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ θ θ − δ δ i i ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ V V ⎝ ⎠ sin cos 0 e 0 e c s cd cs

CP Paper with Maskawa 6-Quark Model ′ ⎛ ⎞ ⎛ ⎞ ⎛ ⎞ d V V V d ⎛ ⎞ ⎛ ⎞ ⎛ ⎞ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ u c t ud us ub ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ′ = ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ s V V V s ′ ′ ′ cd cs cb ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ d s b ⎜ ⎟ ⎜ ⎟ ⎜ ⎟ ′ ⎝ ⎠ ⎝ ⎠ ⎝ ⎠ b V V V b td ts tb ( ) ⎛ ⎞ − λ λ λ ρ − η ⎛ ⎞ 2 3 1 2 A i V V V ⎜ ⎟ ⎜ ⎟ ud us ub ≈ − λ − λ λ 2 2 ⎜ ⎟ V V V 1 2 A ⎜ ⎟ ⎜ ⎟ cd cs cb ( ) ⎜ ⎟ λ − ρ − η − λ ⎝ ⎠ 3 2 V V V 1 1 A i A ⎝ ⎠ td ts tb • 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 b d d b B : : B d d 1981 Bigi, Sanda B-Factory B : b u u b B : u u B-Mesons

E(e − )=8GeV, E(e − )=9GeV, E(e + )=3.5GeV E(e + )=3.1GeV Feature Finite angle beam crossing Zero angle beam crossing 1994 1993 May 1999 – May 1999 – still running Apr. 2008 L peak = 1.7 × 10 34 /cm 2 /s Friendly competition of two experiments over a decade L peak = 1.2 × 10 34 /cm 2 /s

BaBar PeP-II

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 Multi-GeV μ -like + PC Super-K 1996 ～ Atmospheric Neutrino 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 ν μ : KEK-PS ν e ： reactor fit_out.0x03.cmb.free.1.shape fit_out.0x03.cmb.free.1.shape 18 18 events/0.25 [ GeV ] events/0.25 [ GeV ] Entries Entries 58 58 1R- μ spectrum 1R- μ spectrum 16 16 Number of events Number of events 14 14 12 12 No oscillation No oscillation 10 10 Oscillation Oscillation 8 8 6 6 4 4 2 2 0 0 0 0 0.5 0.5 1 1 1.5 1.5 2 2 2.5 2.5 3 3 3.5 3.5 4 4 4.5 4.5 5 5 1 1 2 2 3 3 4 4 [ GeV ] [ GeV ] E ν rec E ν rec ν μ disapearance ν e disapearance

Lepton Flavor Mixing T2K experiment ν μ created at JPARC Super-K Aiming to discover ν e appearance