LASER SPECTROSCOPY OF METASTABLE STATES IN THE UPSILON=2 CASCADE OF ANTIPROTONIC HE-3

Citation
Fj. Hartmann et al., LASER SPECTROSCOPY OF METASTABLE STATES IN THE UPSILON=2 CASCADE OF ANTIPROTONIC HE-3, Physical review. A, 58(5), 1998, pp. 3604-3610
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
ISSN journal
1050-2947
Volume
58
Issue
5
Year of publication
1998
Pages
3604 - 3610
Database
ISI
SICI code
1050-2947(1998)58:5<3604:LSOMSI>2.0.ZU;2-B
Abstract
The pressure dependence of the metastable-state lifetimes in antiproto nic He-3 atoms (p) over bar-He-3(+) was studied using the recently obs erved laser resonance transition (n,l)=(36,33)-->(35,32) in the v=n-/- 1=2 cascade. To this end antiprotons from the Low Energy Antiproton Ri ng (LEAR) at CERN were extracted in approximately 200-ns-long bunches with about 10(8) (p) over tilde per bunch and stopped in a He-3 gas ta rget. Time spectra of delayed annihilation products were taken with th e help of a Cerenkov counter with a gated photomultiplier. Under our e xperimental conditions, p = 136-690 mbars and T= 5.8 K, the lowest met astable level (36,33) was found to be much shorter lived than the corr esponding state (37,34) in the v= 2 cascade of (p) over bar-He-4(+). I t was strongly quenched at pressures above 500 mbars, whereas the high er states in the cascade remained nearly unaffected. This enabled us t o investigate the (37,34)-->(36,33) transition by resonant laser deexc itation. Its wavelength was found to be lambda=524.155+/-0.004 nm, onl y 6 ppm lower than the theoretical value given by Korobov and Bakalov [Phys. Rev. Lett. 79, 3379 1997)] after including relativistic correct ions. [S1050-2947(98)06611-6].