title: Photodetachment of positronium negative ions.
abstract: Photodetachment of the positronium negative ion, a bound state of one positron and two electrons, has been observed. Development of a method to produce the ions efficiently using a Na coated tungsten surface has enabled the first observation of the photodetachment. The obtained lower limit of the photodetachment cross section for the wavelength of 1064 nm is consistent with the theoretical calculations reported so far. The experimental field developed in the present work gives new opportunities to explore the quantum mechanical three-body problem and to develop energy-tunable positronium beams.
authors.affiliation: Department of Physics, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Michishio
authors.forename: T
authors.initials: T
authors.lastname: Tachibana
authors.forename: H
authors.initials: H
authors.lastname: Terabe
authors.forename: A
authors.initials: A
authors.lastname: Igarashi
authors.forename: K
authors.initials: K
authors.lastname: Wada
authors.forename: T
authors.initials: T
authors.lastname: Kuga
authors.forename: A
authors.initials: A
authors.lastname: Yagishita
authors.forename: T
authors.initials: T
authors.lastname: Hyodo
authors.forename: Y
authors.initials: Y
authors.lastname: Nagashima