For decades, the big guns of American science have been the U.S. Department of Energy's particle colliders, which investigate the nature of matter by accelerating subatomic particles and smashing them together. Colliders at the Fermi National Accelerator Laboratory (Fermilab), Stanford Linear Accelerator Center (SLAC) and Brookhaven National Laboratory have discovered exotic particles such as the top quark and revealed phenomena that hint at new laws of physics. But this great American enterprise, like so many others, is now moving overseas. While the Europeans and Japanese build new particle accelerators, the U.S. is poised to shut down its premier colliders at...