1. February 12, 2003ACFA LC Symposium 1 JLC Physics Yasuhiro Okada (KEK) ACFA LC Symposium February 12, 2003,Tsukuba, Japan

2. ACFA LC Symposium2 February 12, 2003 Fundamental questions in elementary particle physics What are the elementary constituents of matter? What are forces acting between them? How did the Universe begin and evolve?

3. ACFA LC Symposium3 February 12, 2003 Our current understanding = The Standard Model of elementary particle physics Matter ： bt s c d u quark     e e lepton Forces: gauge force

4. ACFA LC Symposium4 February 12, 2003 Developments of the Standard Model (SM) quark leptongauge principle Higgs mechanism “ Proposal of the Standard Model “ u,d,s e,  photon charm (SPEAR,AGS)   (SPEAR) 1970 1980 1990 2000 bottom (FNAL) gluon (PETRA) top (TEVATRON) gluon-coupling (TRISTAN) W, Z bosons ( ) gauge-interaction (SLC, LEP) KM mechanism for CP violation (KEKB, PEP-II) (Mass generation) No experimental confirmation

5. ACFA LC Symposium5 February 12, 2003 Time Energy Temp. SUSY GUT Superstring See-saw neutrino Electroweak phase transition Inflation 100 GeV Strong int. EM int. Gravity Planck energy Quest for physics beyond the SM Need a higher energy than 100 GeV. Unification Supersymmetric grand unified theory, Superstring. Neutrino mass SuperKamokande, Cl,Ga, exp., K2K, SNO, KamLAND, … Cosmology Dark matter, Baryogenesis, Inflation,… Weak int.

6. ACFA LC Symposium6 February 12, 2003 Two types of accelerators: Electron-positron collider & Hadron machine Discovery of new particles J/  charm),  gluon J/  (charm), b, W, Z, t Establishment of new mechanisms/principles Gauge principle CP violation Future machine LHC (2007- )JLC

7. ACFA LC Symposium7 February 12, 2003 Worldwide consensus on construction of an electron-positron linear collider (LC) A worldwide consensus in the high energy physics community has been reached to construct an electron- positron LC which can operate concurrently with CERN LHC. Physics and experiments for LC with the center-of-mass energy of up to 500 GeV have been examined. JLC-I (1992) ACFA LC report (2001) TESLA TDR (2001) LC physics resource book for Snowmass 2001

8. ACFA LC Symposium8 February 12, 2003 Goals of JLC physics 1. Higgs physics ( Electroweak symmetry breaking and mass-generation) 2. Direct signals for new physics (SUSY, extra-dimensions, …) 3. Precision study on top and gauge bosons 4. “Unexpected” new signals

9. ACFA LC Symposium9 February 12, 2003 Higgs physics Higgs Field Fills everywhere in the Universe. Breaks the electroweak symmetry. Provides masses to quarks, leptons and gauge bosons. A new particle is predicted. “Higgs boson” Studio R

10. ACFA LC Symposium10 February 12, 2003 Higgs boson search The Higgs boson: Not yet found experimentally. 114 GeV < Mh < 193 GeV (95%CL) for the SM Higgs boson. The Higgs hunting will be continued at TEVATRON and LHC. LHC Higgs search TEVATRON Higgs search

11. ACFA LC Symposium11 February 12, 2003 JLC = A Higgs factory Luminosity = 500 /fb, Ecm=300 GeV Over 100,000 Higgs bosons can be produced at JLC. Higgs boson signal

12. ACFA LC Symposium12 February 12, 2003 Higgs coupling measurements Coupling-mass relation Higgs boson branching ratios Top Yukawa coupling (Ecm >500 GeV) Mass-generation mechanism The Higgs vacuum-expectation-value Particle mass Higgs coupling constant c b t

13. ACFA LC Symposium13 February 12, 2003 Higgs potential = Origin of EW symmetry breaking The first access to the Higgs potential through double Higgs-boson production. Need a higher energy for a precise measurement of the self-coupling constant. ACFA Higgs working group

14. ACFA LC Symposium14 February 12, 2003 More than one Higgs boson? Direct and indirect searches for heavy Higgs bosons at JLC. ACFA Higgs working group

15. ACFA LC Symposium15 February 12, 2003 Photon-photon collider JLC can have an additional interaction point with photon- photon collisions. The heavy Higgs boson can be produced up to 400 GeV for 500 GeV LC. Laser e - beam a few mm    H/A

16. ACFA LC Symposium16 February 12, 2003 Supersymmetry (SUSY) Studio R SUSY = Extension of the Einstein’s relativity (Extension of space-time concept.) SUSY-partner particles W,Z,  H gluon lepton quark neutralino, chargino gluino slepton squark Ordinary particleSuper-particle

17. ACFA LC Symposium17 February 12, 2003 SUSY particle search Smuon production and decay Dark matter candidate? Smuon and neutralino masses are determined to 1% or better.

18. ACFA LC Symposium18 February 12, 2003 Proving a new principle Test of the gaugino GUT relation Test of a SUSY relation Selectron production From selectron and chargino productions

19. ACFA LC Symposium19 February 12, 2003 Determining SUSY breaking mechanism LHC: Squark and gluino production and cascade decay JLC: Slepton, neutlarino, and chargino pair-production Combined analysis SUSY breaking scenario SUSY particle masses Energy scale G.A.Blair, W.Porod,and P.M.Zerwas

20. ACFA LC Symposium20 February 12, 2003 Large extra-dimensions Inspired by superstring theory, a scenario with large extra- dimension is proposed. Studio R Quarks, leptons, and gauge bosons live in a 3-dimensional wall. Gravity can propagate in 3+n dimensional space. graviton quark, lepton, gauge boson

21. ACFA LC Symposium21 February 12, 2003 Search for extra-space at JLC Graviton emission to extra-space The size and number of the extra-space may be determined at JLC. # of extra-dimensional space K.Odagiri

22. ACFA LC Symposium22 February 12, 2003 Precision study on Top and W boson Top: The heaviest particle discovered so far. Anomalous coupling measurements of top and W boson production. Physics beyond the SM Top quark threshold scan Top production threshold scan Precise determination of mass and width

23. ACFA LC Symposium23 February 12, 2003 Detector of JLC The state-of-the-art detector Very precise determination of momentum and energy of out-going particles Heavy quark flavor tagging. Identifying “invisible” particles. Good timing resolution. Much cleaner environment compared to the LHC experiment.

24. ACFA LC Symposium24 February 12, 2003 Detector R&D for JLC Vertex detector test module Jet chamber test module 12 ton test module of the calorimeter Present Framework; ACFA working group. (Work by 15 institutes of Japan, Korea and the Philippines) Collaboration with Europe is developing (UK, Germany, Russia) Collaboration with North America, under discussion.

25. ACFA LC Symposium25 February 12, 2003 1. Higgs physics Determination of Higgs couplings Origin of masses. Higgs potential Dynamics of the electroweak symmetry breaking. 2. Direct signals for new physics Discovery of SUSY or extra-dimensions Change of the space- time concept. 3. Precision study on top and gauge bosons Measurements of basic parameters of physics. 4. “Unexpected” new signals Advantage of an energy-frontier electron-positron collider. Summary of physics goals

26. ACFA LC Symposium26 February 12, 2003 Concurrent operation of JLC and LHC Particle discovery Establishing new principles Squark/gluino cascade decays Slepton/chargino/ neutralino JLC SUSY breaking mechanism Proof of SUSY LHC Supersymmetry spin/coupling measurements TEVATRON Higgs boson mass-generation mechanism Spin/parity Coupling measurements Higgs self-coupling LHC JLC Higgs physics TEVATRON

27. ACFA LC Symposium27 February 12, 2003 Physics research covered by JLC 1 st stage: Ecm =210 -500 GeV, Luminosity = ~ 200/fb x several years. 2 nd stage: Ecm = 1 TeV or more.

28. ACFA LC Symposium28 February 12, 2003 Conclusions Goals of research at JLC are to open a new era of elementary particle physics through critical discoveries which lead to new fundamental principles of Nature. (Origin of mass, new concept on space-time structure, vacuum structure of the Universe, etc.) Rich physics programs are expected for the first stage of the JLC experiment with the center-of- mass energy of up to 500 GeV. Energy upgrade to 1TeV or more is important.