TY - JOUR

T1 - Laser spectroscopy of metastable states in the [Formula Presented] cascade of antiprotonic [Formula Presented]

AU - Hartmann, F. J.

AU - Ketzer, B.

AU - Maierl, C.

AU - Pohl, R.

AU - von Egidy, T.

AU - Hayano, R. S.

AU - Hori, M.

AU - Ishikawa, T.

AU - Tamura, H.

AU - Torii, H. A.

AU - Kumakura, M.

AU - Morita, N.

AU - Sugai, I.

AU - Horváth, D.

AU - Eades, J.

AU - Widmann, E.

AU - Yamazaki, T.

PY - 1998

Y1 - 1998

N2 - The pressure dependence of the metastable-state lifetimes in antiprotonic [Formula Presented] atoms [Formula Presented] was studied using the recently observed laser resonance transition [Formula Presented] in the [Formula Presented] cascade. To this end antiprotons from the Low Energy Antiproton Ring (LEAR) at CERN were extracted in approximately 200-ns-long bunches with about [Formula Presented] per bunch and stopped in a [Formula Presented] gas target. Time spectra of delayed annihilation products were taken with the help of a Čerenkov counter with a gated photomultiplier. Under our experimental conditions, [Formula Presented] and [Formula Presented] the lowest metastable level [Formula Presented] was found to be much shorter lived than the corresponding state (37,34) in the [Formula Presented] cascade of [Formula Presented] It was strongly quenched at pressures above 500 mbars, whereas the higher states in the cascade remained nearly unaffected. This enabled us to investigate the [Formula Presented] transition by resonant laser deexcitation. Its wavelength was found to be [Formula Presented] only 6 ppm lower than the theoretical value given by Korobov and Bakalov [Phys. Rev. Lett. 79, 3379 1997)] after including relativistic corrections.

AB - The pressure dependence of the metastable-state lifetimes in antiprotonic [Formula Presented] atoms [Formula Presented] was studied using the recently observed laser resonance transition [Formula Presented] in the [Formula Presented] cascade. To this end antiprotons from the Low Energy Antiproton Ring (LEAR) at CERN were extracted in approximately 200-ns-long bunches with about [Formula Presented] per bunch and stopped in a [Formula Presented] gas target. Time spectra of delayed annihilation products were taken with the help of a Čerenkov counter with a gated photomultiplier. Under our experimental conditions, [Formula Presented] and [Formula Presented] the lowest metastable level [Formula Presented] was found to be much shorter lived than the corresponding state (37,34) in the [Formula Presented] cascade of [Formula Presented] It was strongly quenched at pressures above 500 mbars, whereas the higher states in the cascade remained nearly unaffected. This enabled us to investigate the [Formula Presented] transition by resonant laser deexcitation. Its wavelength was found to be [Formula Presented] only 6 ppm lower than the theoretical value given by Korobov and Bakalov [Phys. Rev. Lett. 79, 3379 1997)] after including relativistic corrections.

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U2 - 10.1103/PhysRevA.58.3604

DO - 10.1103/PhysRevA.58.3604

M3 - Article

AN - SCOPUS:0032209423

VL - 58

SP - 3604

EP - 3610

JO - Physical Review A - Atomic, Molecular, and Optical Physics

JF - Physical Review A - Atomic, Molecular, and Optical Physics

SN - 1050-2947

IS - 5

ER -