The global competition to build the next huge linear electron-positron collider, a 30- kilometer-long machine aimed at answering fundamental questions in physics, appears to have become a two-horse race. Four teams are working on designs for the multibillion-dollar device, which would pick up the baton from the Large Hadron Collider now under construction at CERN near Geneva. But last week, at a meeting of the International Committee for Future Accelerators, Germany's TESLA collider and a joint bid from the Stanford Linear Accelerator Center (SLAC) in California and Japan's KEK particle physics lab emerged as the clear front-runners.
A panel that has spent 15 months vetting the four entries has identified about 30 R&D issues that must be addressed before physicists try to sell their favored design to funders. But panel chair Greg Loew of SLAC told Science that there are no apparent technical "showstoppers" for the top two entries.
