symposium summary: where we are

Symposium Summary:Where We Are

Jeffrey A. Appel, Fermilab

IV International Symposium of

LHC Physics and Detectors

Fermilab, May 1-3 2003

“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

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?

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.

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.

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.

Where We Are wrt the LHCBuilding 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.

Direct calculation of the probability for each eventThe probability depends on all measured momenta of the final state lepton and jetsEach event’s contribution depends on how well it is measuredTo 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 4.0 GeV 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.

New preliminary DZero top quark mass measurement using Run I data

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.

However, Concerns of an OutsiderIndustrial 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!

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

All channel plot

Ivor Fleck ATLAS, Early physics reach

Large cross-section for squark and gluino production

SUSY

Decay chain leads to

- high pT jets

- large missing ET

- isolated leptonsDiscovery of SUSY is easy for masses below 2 TeV

Ivor Fleck ATLAS, Early physics reach

ATLAS 5 discovery curves

~ 100 days :

up to 2.3 TeV

~ “10 days” :

up to 2 TeV

~ “ 1 day” :

up to 1.5 TeV

Bulk Particle Production @ RHIC

1. Initial Conditions/Energy Density: > 5 GeV/fm3

2. Thermalization:

3. Hadrochemistry: Tch ~ 180 MeV, B~25MeV

4. Expansion Dynamics: Tth ~ 110 MeV, <T> ~ 0.6c

<fo>~ 10 fm/c, fo~ 0-3

fm/c Consistent Description of Final State

But we’re missing a picture of Dynamical Evolution

Gunther Roland/MIT LHC2003

ALICE Physics Phases of Strongly Interacting Matter

• Exploring the phase diagram of strongly interacting matter

• LHC provides access to the high T, vanishing B QGP phase

Lattice QCD, B = 0Lattice QCD, B = 0

LHCLHC

Christoph Blume, LHC Symposium 2003, May 1-3, Fermi National Accelerator Lab.

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.

The Physics Landscape: Pb+Pb Collisions SPS->RHIC->LHC

d

Extrapolation of RHIC results favors low values

Russell Betts - UIC

Xdim: Direct Graviton Production Signal

100 fb-1

Jet + missing EtSignals

Significance

Events for high luminosity

100 fb-1, for Etjet > 1 TeV

Bing Zhou Univ. of Mich. 5/2/03

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.

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!

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.