Symposium Summary: Where We Are

1. Symposium Summary:Where We Are Jeffrey A. Appel, Fermilab IV International Symposium of LHC Physics and Detectors Fermilab, May 1-3 2003

2. “The End of Science” And now that science – true, pure, empirical science – has ended, what else is there to believe in. John Horgan p226, “The End of Science” Addison-Wesley, 1996

3. We are here to reaffirm the opposite. Empirical science is alive and well. Even more, we are at the threshold of a new era, with a new leap beyond the current energy frontier. Following the excellent presentations on our future at this symposium, it is perhaps worthwhile to pause a moment and consider the most recent leaps of the energy frontiers of previous eras. What do they suggest?

4. The ISR and the “200 GeV Machine” What happened when these machines turned on? Available energy jumped from ~8 GeV with 30 GeV beams to 20-50 GeV of available energy. A new energy frontier opened. We were surprised, even shocked by how different the world seemed. Almost immediately, we saw the advent of high- pt events. Backgrounds for many planned experiments were orders of magnitude larger than expected. More fundamentally, we had (as we now understand it) the effects of the quark substructure of hadrons. And, we started to produce particles essentially undreamed of before – well, dreamed of by only a few foolhardy visionaries.

7. The Big CERN and Fermilab Hadron Colliders What happened when these machines turned on? Available energy jumped from ~30 GeV of available energy to 0.6 and 2 TeV. A much bigger step, this time. And, we were surprised – maybe not so much by a new energy scale which was predicted (W and Z masses), but by how heavy the top quark is. We have seen no direct evidence of any of the suggested new particles: sequential W, Z bosons, Higgs, SUSY, nor techni-particles. We have not seen a break in pt spectra, the onset of a new level in the hierarchy of matter, any suggestion of something more fundamental than quarks and leptons.

8. Real, Substantial Progress! It has been very good to see the progress over the past year on the LHC, and on detectors, software, and physics planning. Happy that civil construction is going well, and magnets getting better. Happy to see so many detector components getting into construction. We have heard about facing real challenges: Technical – e.g., DMILL, some electronics noise and yield issues, material budgets, radiation damage effects Financial – scope changes, additional funding Schedule – continuous review and adjustments (e.g., test beams) Happy to see some full system tests, and indications that planning for commissioning is getting serious attention.

9. Where We Are wrt the LHC Building detectors, solving technical and managerial problems. Building expanded collaborations and new tools to deal with the new sociology (int. collab., management, GRID). Expanding physics goals (heavy ion collisions in ATLAS and CMS, jets in ALICE, B physics everywhere. “Design/engineering updates [in simulations] lead to deterioration in performance.” But, better algorithms; e.g., tracking and tagging, compensate. Mock data challenge preparations cannot be over-valued, both for the physics and for the computing environment debugging. Even more, better motivation will come from the data itself.

10. New preliminary DZero top quark mass measurement using Run I data • Direct calculation of the probability for each event • The probability depends on all measured momenta of the final state lepton and jets • Each event’s contribution depends on how well it is measured • To calculate signal and background probabilities the parton differential cross sections are convoluted with the parton distribution functions and the detector resolution .The probabilities are also corrected by the detector, trigger and reconstruction acceptances. Mt= 180.1  3.6 4.0GeV preliminary • Improvement in statistical error is equivalent to an factor of 2.4 in the size of the data sample. • The relative error in this result is 3%, compare to 2.9% from the previous CDF and DØ combined average for all channels.

12. Your Progress is Important to Us. Your progress is important to us at Fermilab. First, for our physics program (CMS) and s.c. magnet program. Mike Witherell noted that only our Tevatron Collider and neutrino programs are larger here. Second, for planning of much of the rest of our program as well. In fact, your progress is important to all of HEP.

13. However, Concerns of an Outsider Industrial scale technology is still new to our community. Not obvious that accelerator components will stay ahead of the “just in time” schedule. Some commercial technologies may not last long enough for our development and construction schedules (DMILL, DSM, networking, and computing components, e.g., Objectivity). More technology decisions than healthy at this stage (CMS pixel size, ATLAS B layer pixel size, CMS ECal electronics, and LHCb HPD/MAP decisions especially). Common computing approaches to save duplication – just starting Testing and commissioning times are getting squeezed almost everywhere – already!

15. A Few Words About the Physics I will show the most frequently referenced transparencies: Higgs SUSY Heavy Ions And two personal favorites: Compositness Extra Dimensions

16. All channel plot Ivor Fleck ATLAS, Early physics reach

17. SUSY ATLAS 5 discovery curves Large cross-section for squark and gluino production ~ 100 days : up to 2.3 TeV ~ “10 days” : up to 2 TeV • Decay chain leads to • high pT jets • large missing ET • isolated leptons ~ “ 1 day” : up to 1.5 TeV Discovery of SUSY is easy for masses below 2 TeV Ivor Fleck ATLAS, Early physics reach

18. Bulk Particle Production @ RHIC • Initial Conditions/Energy Density: > 5 GeV/fm3 • Thermalization: • Hadrochemistry: Tch ~ 180 MeV, mB~25MeV • Expansion Dynamics: Tth ~ 110 MeV, <bT> ~ 0.6c <tfo>~ 10 fm/c, Dtfo~ 0-3 fm/c Consistent Description of Final State But we’re missing a picture of Dynamical Evolution Gunther Roland/MIT LHC2003

19. LHC ALICE Physics Phases of Strongly Interacting Matter • Exploring the phase diagram of strongly interacting matter • LHC provides access to the high T, vanishing mB QGP phase Lattice QCD, mB = 0 Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

20. Why Heavy Ion Physics at the LHC? The “missing picture of Dynamical Evolution” may require: More dynamic range in kinematic variables Longer time for escaping partons to feel effects of QGP Larger samples of charm, bottom, and onium All these should be available at the LHC.

21. The Physics Landscape: Pb+Pb Collisions SPS->RHIC->LHC dh Extrapolation of RHIC results favors low values Russell Betts - UIC

23. Xdim: Direct Graviton Production Signal Jet + missing Et Signals Events for high luminosity 100 fb-1, for Etjet > 1 TeV 100 fb-1 Significance Bing Zhou Univ. of Mich. 5/2/03

24. Where We Are – at a Threshold? In many ways, physics has never been more exciting. We are about to extend the energy frontier by a factor of 7. We have an excellent model of what we have seen already. We know that our model is incomplete, and have detailed predictions which can be tested definitively soon. We are not at the “end of science,” but hopefully at the threshold of exciting new science. What will the new science be? I don’t really know. However, personally, I expect we will have major surprises. I expect surprises comparable to those when ISR and Fermilab began.

25. My Message In the face of the new energy frontier, be prepared to read out working detectors, be prepared for analysis of early, imperfect data, be prepared for discovery, be prepared for surprises in signal and backgrounds, and be prepared to think new thoughts! Good luck!

26. Thank You To the Organizers. To the Support Staff. To the Speakers (specially those who responded to my request for advance word on their presentations). To All the Participants.