MISC

2004年7月

Populations and lifetimes in the v=n-l-1=2 and 3 metastable cascades of (p)over-barHe(+) measured by pulsed and continuous antiproton beams

PHYSICAL REVIEW A
  • M Hori
  • J Eades
  • E Widmann
  • T Yamazaki
  • RS Hayano
  • T Ishikawa
  • HA Torii
  • T von Egidy
  • FJ Hartmann
  • B Ketzer
  • C Maierl
  • R Pohl
  • M Kumakura
  • N Morita
  • D Horvath
  • Sugai, I
  • 全て表示

70
1
記述言語
英語
掲載種別
DOI
10.1103/PhysRevA.70.012504
出版者・発行元
AMER PHYSICAL SOC

The time evolution of the state populations in the v=n-l-1=2 and 3 metastable cascades of antiprotonic helium ((p) over bar He-4(+)) atoms were studied using laser spectroscopy. The antiprotonic states (n,l)=(39,35), (40,36), and (41,37) in the v=3 cascade were estimated to initially contain, respectively, (0.28+/-0.04)%, (0.06+/-0.02)%, and (0.02+/-0.01)% of the antiprotons stopped in the helium target, while the corresponding values for states (37,34), (38,35), and (39,36) in the v=2 cascade were (0.21+/-0.04)%, (0.49+/-0.07)%, and (0.19+/-0.07)%. The shortening of the state lifetimes due to collisions between (p) over bar He+ and helium atoms was studied. As the atomic density of the target was increased from rho=2x10(20) to 2x10(21) cm(-3), the lifetime of state (37,34) decreased by an order of magnitude, whereas the higher states (38,35) and (39,35) were relatively unaffected. Between densities rho=6x10(20) and 2x10(22) cm(-3), a short-lived component with a time constant tausimilar to0.2 mus appeared at early times in the delayed annihilation time spectrum of (p) over bar He+, while the total fraction of long-lived antiprotons decreased from 3.0 to 2.5%. These effects were caused by the lifetime-shortening of specific (p) over bar He+ states such as (37,34).

リンク情報
DOI
https://doi.org/10.1103/PhysRevA.70.012504
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000223273200054&DestApp=WOS_CPL
ID情報
  • DOI : 10.1103/PhysRevA.70.012504
  • ISSN : 2469-9926
  • eISSN : 2469-9934
  • Web of Science ID : WOS:000223273200054

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