Number 11 (Story #2), December 3, 1990 by Phillip F. Schewe and Ben Stein LIGHT-FRONT TAMM-DANCOFF (LFTD) theory attempts to describe how particles interact via the strong interaction in a way that avoids various problems that have troubled other theories in recent years. Scientists at the Ohio State University, including Kenneth G. Wilson (614-292-8686) and Robert J. Perry (614-292-6506), begin by using a coordinate system in which light moving in one direction stands still; in other words, the coordinate system moves with light along a "light front." This insures that pairs of virtual particles cannot pop out of the vacuum and go off in opposite directions (an occurrence that plagues normal field theory) because everything is flung backward. A second step involves a "Tamm-Dancoff truncation," named for I. Tamm and S.M. Dancoff, which cuts off the number of possible virtual particles that "mediate" the interaction. Theorists at Ohio State and elsewhere are hoping that in coming years the LFTD approach will help to solve a number of problems in nuclear physics and particle physics. (Upcoming article in Physical Review Letters.)