Abstract

Comparisons of antiproton and proton cyclotron frequencies yield the ratio of inertial masses The fractional uncertainty of 5 × 10^* is 1000 times more accurate than previous measurements of this ratio using exotic atoms and is the most precise test of CPT invariance with baryons. Independent comparisons to electrons yield the mass ratios M(p)/M(e-) = 1836.152638 + 0.000083 and M(p)/M(e-) = 1836.152660 + 0.000088. For these measurements, cryogenic antiprotons (near4 K), were stored in a Penning trap for up to 2 months—much longer than antiprotons have been previously stored.

© 1990 Optical Society of America