Hidden Worlds: Hunting for Quarks in Ordinary Matter.

TIMOTHY PAUL SMITH

Protons and neutrons are each made up of exactly three particles known as quarks. There are two common types of quarks known as the up and down quarks. A proton is made up of one down and two up quarks; the neutron reverses those numbers. This knowledge in and of itself is interesting, considering that no one has actually seen a quark, nor will they ever. Smith, a nuclear physicist, studies these infinitesimally small things and explains how he and other scientists know what they know without the benefit of ever being able to see what they are working on. Taking readers to the miles-long particle accelerators used to magnify matter in fine detail, Smith introduces the physicists working in this field, who in turn help him explain in this book what quarks are and how they act. The scientists ponder how quarks arrange themselves, what other combinations nature can make, how quarks hold nuclei together, and what else might be happening in the hidden world that these scientists love. The answers to these questions are founded in a few simple principles. Princeton U Pr, 2003, 178 p., b&w illus., hardcover, $24.95.