Number 92 (Story #2), August 19, 1992 by Phillip F. Schewe and Ben Stein THE ELECTRICAL CHARGE OF ANTIPROTONS AND POSITRONS has been studied using data from cyclotron-frequency experiments (which monitor the behavior of particles in a magnetic field) comparing protons with antiprotons and electrons with positrons, as well as spectroscopic measurements of short-lived states containing antimatter, such as positronium and antiprotonic atoms. Richard Hughes of Los Alamos and B.I. Deutch of the University of Aarhus in Denmark have calculated that the charges of the positron and electron are equal to about one part in 10**8, while the charge of the antiproton equals that of the electron to about one part in 10**5 (Phys. Rev. Lett., 27 July). The precision of these calculations would improve if researchers could study antihydrogen, an atom consisting entirely of antimatter. (Science News, 15 August 1992.)