Subatomic scrutiny from Jefferson lab.

One hundred years after the discovery of the electron--the first known subatomic particle--physicists are using the particles to reveal the quirks of quarks, which constitute protons and neutrons. Now, scientists have obtained the first results from high-speed collisions between electrons and other particles at the Thomas Jefferson National Accelerator Facility in Newport News, Va.

Physicists first identified quarks in 1968 by bouncing isolated bursts of high-energy particles off protons, providing a brief snapshot of the quarks inside. The Jefferson accelerator, which began operating last year, sends continuous beams of electrons with an energy of 4 billion electronvolts along its nearly mile-long tunnel and into atomic targets, providing an improved picture of quarks as they interact and combine to create other particles.

The new pictures reveal some novel phenomena. In one experiment, protons were bumped out of the nucleus more easily than expected. In other instances, however, increasing amounts of energy failed to kick more protons out of the nucleus, hinting that quarks somehow absorbed the extra energy. A clear conception of quarks and their interactions will require more experiments, says Jefferson lab's Larry Cardman.