1. Future Directions in Experimental Nuclear and Particle Physics Barry Barish Bacher Symposium Caltech 5-Nov-05 Bacher at the Caltech Synchrotron Robert Bacher

2. 5-Nov-05Bacher Symposium2 Bacher and the Energy Frontier In the Spring of 1949, the Institute announced plans to build a one-billion volt ("1 BeV") electron accelerator. Robert Bacher, chairman of Caltech's Physics Division, stated: "The purpose of the new accelerator will be to seek additional knowledge about the nature of the forces that hold atomic nuclei together." The new accelerator, the synchrotron, would be the most powerful machine of its type ever built.

3. 5-Nov-05Bacher Symposium3 Photoproduction of Excited States of the Nucleon Bacher

4. 5-Nov-05Bacher Symposium4 This led to higher energy machines: Electron-Positron Colliders Bruno Touschek built the first successful electron-positron collider at Frascati, Italy (1960) with help from Bob Walker (Caltech) and others Eventually, went up to 3 GeV ADA

5. 5-Nov-05Bacher Symposium5 But, not quite high enough energy …. Discovery Of Charm Particles and 3.1 GeV Burt Richter Nobel Prize SPEAR at SLAC

6. 5-Nov-05Bacher Symposium6 The rich history for e + e - continued as higher energies were achieved … DESY Petra Collider

7. 5-Nov-05Bacher Symposium7 Electron Positron Colliders The Energy Frontier

8. 5-Nov-05Bacher Symposium8 The Future Three Complementary Probes Neutrinos as a Probe –Particle physics and astrophysics using a weakly interacting probe High Energy Proton Proton Colliders –Opening up a new energy frontier ( ~ 1 TeV scale) High Energy Electron Positron Colliders –Precision Physics at the new energy frontier

9. 5-Nov-05Bacher Symposium9 What makes the sun shine? 4 1 H  4He + 2e + + 2 v e + energy

10. 5-Nov-05Bacher Symposium10 Neutrinos observed from the sun ! Davis and Bahcall Koshiba Superkamiokande

11. 5-Nov-05Bacher Symposium11 But, too few neutrinos … If neutrinos have mass, then as conjectured earlier by Bruno Pontecorvo, neutrinos could “oscillate” from one type to another. In this case, some of the original electron neutrinos made in the sun convert to other neutrinos on trajectory to the earth

12. 5-Nov-05Bacher Symposium12 Puzzle resolved … neutrinos oscillate SNO (Canada) used D 2 0 to detect other neutrino types KamLAND used terrestrial neutrinos from reactors, observes oscillations (McKeown)

13. 5-Nov-05Bacher Symposium13 Neutrinos – The Future Long baseline neutrino experiments – Create neutrinos at an accelerator or reactor and study at long distance when they have oscillated from one type to another. MINOS C Peck, H Newman, D Michael

14. 5-Nov-05Bacher Symposium14 Neutrinos – The Big Questions Why are neutrino masses so small ? Are the neutrinos their own antiparticles? What is the separation and ordering of the masses of the neutrinos? Neutrinos contribution to the dark matter? CP violation in neutrinos, leptogenesis, possible role in the early universe and in understanding the particle antiparticle asymmetry in nature?

15. 5-Nov-05Bacher Symposium15 Accelerators and the Energy Frontier Large Hadron Collider CERN – Geneva Switzerland H Newman, E Hughes

16. 5-Nov-05Bacher Symposium16 Accelerators and the Energy Frontier International Linear Collider B Barish

17. 5-Nov-05Bacher Symposium17 Why e + e - Collisions ? elementary particles well-defined –energy, –angular momentum uses full COM energy produces particles democratically can mostly fully reconstruct events

18. 5-Nov-05Bacher Symposium18 Electroweak Precision Measurements What causes mass?? The mechanism – Higgs or alternative appears around the corner

19. 5-Nov-05Bacher Symposium19 The linear collider will measure the spin of any Higgs it can produce by measuring the energy dependence from threshold How do you know you have discovered the Higgs ? Measure the quantum numbers. The Higgs must have spin zero !

20. 5-Nov-05Bacher Symposium20 What can we learn from the Higgs? Straight blue line gives the standard model predictions. Range of predictions in models with extra dimensions -- yellow band, (at most 30% below the Standard Model The red error bars indicate the level of precision attainable at the ILC for each particle Precision measurements of Higgs coupling can reveal extra dimensions in nature

21. 5-Nov-05Bacher Symposium21 New space-time dimensions can be mapped by studying the emission of gravitons into the extra dimensions, together with a photon or jets emitted into the normal dimensions. Linear collider Direct production from extra dimensions ?

22. 5-Nov-05Bacher Symposium22 Is there a new symmetry in nature? Supersymmetry The breaking of the symmetry between electromagnetic and weak interactions though the Higgs mechanism introduces several anomalies, which point towards physics beyond the standard model. A particularly attractive scenario is supersymmetry (SUSY), which would eliminates the anomalies from the Higgs section and predicts SUSY partners for all known particles. These particles should be detected at the LHC and ILC

23. 5-Nov-05Bacher Symposium23 Designing a Linear Collider Superconducting RF Main Linac

24. 5-Nov-05Bacher Symposium24 Superconducting RF Cavities High Gradient Accelerator 35 MV/meter -- 40 km linear collider

25. 5-Nov-05Bacher Symposium25 Improved Processing Electropolishing Chemical Polish Electro Polish

26. Internationl Linear Collider Timeline 2005 2006 2007 2008 2009 2010 Global Design EffortProject Baseline configuration Reference Design ILC R&D Program Technical Design Expression of Interest to Host International Mgmt

27. 5-Nov-05Bacher Symposium27 Conclusions We have determined a number of very fundamental physics questions to answer, like …. –What determines mass? –What is the dark matter? –Are there new symmetries in nature? –What explains the baryon asymmetry? –and others discussed by Gukov We are developing the tools to answer these questions and discover new ones –Neutrino Physics –Large Hadron Collider –International Linear Collider The next era of particle physics will be very exciting

28. 5-Nov-05Bacher Symposium28 Bacher’s Legacy Identify the most fundamental physics questions and develop (or use the tools) needed to address those questions Those principles have guided the Caltech nuclear and particle physics efforts for several decades and will continue into the future.