Direct measurement of transition frequencies in isolated pHe+ atoms, and new CPT-violation limits on the antiproton charge and mass.
A radio frequency quadrupole decelerator and achromatic momentum analyzer were used to decelerate antiprotons and produce p4He+ and p3He+ atoms in ultra-low-density targets, where collision-induced shifts of the atomic transition frequencies were negligible. The frequencies at near-vacuo conditions were measured by laser spectroscopy to fractional precisions of (6-19) x 10(-8). By comparing these with QED calculations and the antiproton cyclotron frequency, we set a new limit of 1 x 10(-8) on possible differences between the antiproton and proton charges and masses.
Hori
M
M
CERN, CH-1211 Geneva 23, Switzerland.
Eades
J
J
Hayano
R S
RS
Ishikawa
T
T
Pirkl
W
W
Widmann
E
E
Yamaguchi
H
H
Torii
H A
HA
Juhász
B
B
Horváth
D
D
Yamazaki
T
T