Can We Make Good Progress in Fundamental Physics Without a Linear Collider? Bruce Schumm U.C. Santa Cruz EPP2010 Town Meeting Stanford Linear Accel- erator Center January 31, 2005

At the same time, the case for the next step has never been more compelling New physics must appear at the ‘Electroweak Scale’ Evidence from astrophysics (large-scale structure, baryon asymmetry) tell us that we are missing a huge piece of the picture. In Winter, 2005, accelerator technology is in hand for the next big step forward (LHC, ILC)

“Every cubic inch of space contains a miracle.” Walt Whitman For all our progress and bluster, we suddenly find out that we have no idea what it’s all made of. A good scientist would go back to the lab…

Standard Model Higgs? Supersymmetry? Large Extra Dimensions? Little Higgs? Extended Gauge Scenarios? GUTS? If we see a bump, then what? Ten plus years of physics studies tell us that, without precision meas- urements (the LC), we are likely to be left in a realm of speculation. Ideally, these would be synchronous with LHC running, but passage of time will not diminish the need for this sort of work. Invisible Higgs? Note: only ob- servable at LC !

: LEP, SLC lep- ton colliders produce ~10 7 Z bosons with precisely under- stood initial conditions DISCOVERY AND DISSECTION: THE ONE-TWO PUNCH OF EXPERIMENTAL PARTICLE PHYSICS 1983: CERN SPS (hadron collider) discovers Z boson, partner of  -decay-mediating weak-force W boson

At UCSC: Linear Collider ‘LSTFE’ project in direct overlap with PTSM proton tomography (radiobiology) program; indirect supporting roles for exptl astrophysics, neurobiology. University-based Innovation/Interdisciplinarity/Education Contributes to education/train- ing at all levels (undergrad, graduate, post-doctoral). Early, exploratory R&D is ideal for smallish, vibrant University programs.

The physics of the Electroweak Scale is one of the most crucial and compelling fundamental questions that face us.We must bring our fullest capacity to bear on this once-in-a-lifetime opportunity. Many years of studies identify the Linear Collider as a necessary component of this work. The technology is at hand. The timescale is right. The preparatory work is already driving the field forward, playing into synergies with other fields, and providing excellent training opportunities to future science and technological leaders both within and without the field. Ideally, the LC and LHC will overlap, but we’ll need the LC in any regard, and the time to prepare is now. Not building the LC would leave a vast gap in our intel- lectual toolkit just when we need those tools the most. Reprise

1983: CERN SPS (hadron collider) discovers Z boson, partner of  -decay-mediating weak-force W boson : LEP, SLC lep- ton colliders produce ~10 7 Z bosons with precisely under- stood initial conditions