title: Direct measurement of transition frequencies in isolated pHe+ atoms, and new CPT-violation limits on the antiproton charge and mass.
abstract: 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.
authors.affiliation: CERN, CH-1211 Geneva 23, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Hori
authors.forename: J
authors.initials: J
authors.lastname: Eades
authors.forename: R S
authors.initials: RS
authors.lastname: Hayano
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: W
authors.initials: W
authors.lastname: Pirkl
authors.forename: E
authors.initials: E
authors.lastname: Widmann
authors.forename: H
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: H A
authors.initials: HA
authors.lastname: Torii
authors.forename: B
authors.initials: B
authors.lastname: Juhász
authors.forename: D
authors.initials: D
authors.lastname: Horváth
authors.forename: T
authors.initials: T
authors.lastname: Yamazaki