Medium Energy Spin Physics

California Institute Of Technology, Pasadena CA

Investigators

Abstract

0072192 Hughes The physics program funded by this grant is directed at the study of the electroweak and strong interactions. Technically, the program focuses on the use of polarized electron beams scattering off polarized and unpolarized targets. The experiments take place at the Jefferson Laboratory in Viriginia and the Stanford Linear Accelerator Center (SLAC) in California. At SLAC, the fixed target program is presently devoted to a precision test of the electroweak theory. By scattering polarized electrons at high energies off unpolarized electrons in a liquid hydrogen target, we are able to perform a precision test of the electroweak mixing angle in a new energy range. The results from this experiment will be sensitive to the existence of new particles and new interactions. At Jefferson Lab, the fixed target program is focused on the scattering of polarized electrons by polarized helium-3 in order to learn information on the internal spin structure of the neutron. Measurements of the neutron spin structure function over a wide range of energies allows for tests of fundamental strong interaction sum rules and provides details on the quark contribution to the neutron's spin.