title: Sub-ppm laser spectroscopy of antiprotonic helium and a CPT-violation limit on the antiprotonic charge and mass.
abstract: Six laser-resonant transitions have been detected in metastable antiprotonic helium atoms produced at the CERN Antiproton Decelerator. They include UV transitions from the last metastable states in the v = n-l-1 = 0 and 1 cascades. Zero-density frequencies were obtained from measured pressure shifts with fractional precisions between 1.3 x 10(-7) and 1.6 x 10(-6). By comparing these with QED calculations and the antiproton cyclotron frequency, we deduce that the antiproton and proton charges and masses agree to within 6 x 10(-8) with a confidence level of 90%.
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: J
authors.initials: J
authors.lastname: Sakaguchi
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