CP Violation and Flavor Mixing

Size: px

Start display at page:

Download "CP Violation and Flavor Mixing"

Scott Warner
5 years ago
Views:

1 CP iolation and Flavor Mixing Makoto Kobayashi KEK and JSPS

2 Plan 1. Introduction to the Standard Model 2. Sakata and His Group 3. The CP Paper with Maskawa 4. Experimental erification at B-factories 5. Lepton Flavor Mixing

3 Introduction to the Standard Model Electron p u d u Proton(p) n Nucleus d d u Atom Neutron(n)

4 Introduction to the Standard Model Fundamental Particles Quark u d c s t b Lepton e μ τ Fundamental Interactions ν e ν μ ν τ Strong Interaction Electro Magnetic Interaction Weak Interaction QCD Weinberg Salam Glashow Theory

5 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 1964 Gell Mann quark model u, d, s u d c s t b e μ τ ν e ν μ ν τ 1973 Kobayashi Maskawa Six Quark Model After 1970

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

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

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

9 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

10 CP Paper with Maskawa 1971 t Hooft : Renormalization of Non-Abelian gauge theory Renormalizable Electro-Weak Theory (Weinberg-Salam-Glashow ) 1973 Kobayashi, Maskawa How to accommodate CP violation What we found Not possible in four-quark models Existence of unknown particles A possible candidate is six-quark model CP iolation 1964 Cronin et al. K L ππ Essential difference between particles and anti-particles

11 CP Paper with Maskawa s c d u Flavor Mixing Mismatch between gauge symmetry and particle spectra = s d s d cs cd us ud CP iolation Complex elements not removable by the phase convention = θ θ θ θ δ δ δ δ cos sin sin cos s d c u i i cs cd us ud i i e e e e

12 ( ) ( ) λ η ρ λ λ λ λ η ρ λ λ λ A i A A i A tb ts td cb cs cd ub us ud b t s c d u = b s d b s d tb ts td cb cs cd ub us ud An imaginary number parameter violates CP CP Paper with Maskawa 6-Quark Model

13 CP Paper with Maskawa 1974 Discovery of J/ψ 1975 Discovery of τ -lepton c-quark 1975 S. Pakvasa, H. Sugawara 1976 J.R Ellis, M-K Gaillard, D. Nanopoulos 1977 Discovery of Υ 1995 Discovery of t-quark b-quark Large CP violation in the B-meson system 1980 Carter, Sanda 1981 Bigi, Sanda B-Factory d : bd bu B d B : B u: : B u db ub B-Mesons

14 E(e )=8Ge, E(e + )=3.5Ge Finite angle beam crossing Feature E(e )=9Ge, E(e + )=3.1Ge Zero angle beam crossing May 1999 still running May 1999 Apr L peak = /cm 2 /s Friendly competition of two experiments over a decade L peak = /cm 2 /s

15 PeP-II BaBar

16 Belle: 14 countries, 59 institutes, about 400 researchers

17 Experimental erification at B-Factories

18 Experimental erification at B-Factories Present Status of CP iolation 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

Neutrino θ Multi-Ge μ-like + PC Super-K 1996~ Earth ν C.R. J.

19 Lepton Flavor Mixing Discovery of neutrino oscillation at Super-Kamiokande using atmospheric neutrinos Atmospheric Neutrino θ Multi-Ge μ-like + PC Super-K 1996~ Earth ν C.R. J.Raaf, Talk at Neutrino 2008 Courtesy of KEK Yoji Totsuka

20 Lepton Flavor Mixing Number of events events/0.25[ge] K2K experiment ν μ : KEK-PS fit_out.0x03.cmb.free.1.shape Entries 58 1R-μ spectrum No oscillation Oscillation KamLAND experiment ν e : reactor [Ge] Eν rec ν μ disapearance ν e disapearance

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

CP VIOLATION AND FLAVOUR MIXING

CP VIOLATION AND FLAVOUR MIXING Nobel Lecture, December 8, 2008 by Makoto Kobayashi KEK, Oho, Tsukuba-shi, 305-0801, and JSPS, Ichibancho, Chiyodaku-ku, Tokyo, 102-8471, Japan. 1. INTRODUCTION We know