Erratum: Laser spectroscopic studies of state-dependent collisional quenching of the lifetimes of metastable antiprotonic helium atoms [Physical Review A 57, 1698 (1998)]
Erratum: Laser spectroscopic studies of state-dependent collisional quenching of the lifetimes of metastable antiprotonic helium atoms [Physical Review A 57, 1698 (1998)]
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勘误表：亚稳态反质子氦原子寿命的状态相关碰撞淬灭的激光光谱研究 [物理评论 A 57, 1698 (1998)]
DOI：
10.1103/physreva.58.1612
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发表时间：
1998
影响因子：
2.9
通讯作者：
T. Yamazaki
中科院分区：
文献类型：
--
作者：
M. Hori;H. Torii;R. Hayano;T. Ishikawa;F. Maas;H. Tamura;B. Ketzer;F. Hartmann;R. Pohl;C. Maierl;M. Hasinoff;T. Egidy;M. Kumakura;N. Morita;I. Sugai;D. Horvath;E. Widmann;J. Eades;T. Yamazaki
据了解，在稠密氦气中停止的所有反质子中，约有 3% 能够存活，平均寿命为 3-4 s 1-6。这是由于亚稳态反质子氦 (p He) 原子 7、8 的形成，它们是由氦核、电子和反质子组成的中性三体库仑系统，尽管与普通氦原子的碰撞频率很高，但它们仍然存在。最近，激光光谱技术 9, 10 已经能够直接测量该原子 10-19 各个状态的跃迁能量和寿命。当围绕普通原子的一个电子被反质子取代时，就会形成反质子原子，反质子被捕获到主量子数为 n M*/me 的高度激发态（M* 和 me 分别是反质子氦核和电子-氦核系统的约化质量。这些原子通常会在 1 ps 内湮灭，这是由于各种级联机制使反质子快速去激发到具有如此小的轨道角动量的状态（l 0, 1,...)，它们与原子核的大量重叠确保了快速吸收。因此，在致密目标中形成的反质子氢 (p p) 原子通过与普通氢原子 20、21 的碰撞斯塔克过程而湮灭，而在比氦重的反质子原子 (Z 2) 中，反质子通过内部俄歇跃迁而级联下来，寿命小于 1 ps 22。在后一个过程中，部分结合能和角动量被吸收。反质子轨道转移到剩余的电子；它被喷射到连续体中，而反质子退激发到能量较低的离子态。然而，反质子氦原子似乎是独特的，因为在初始捕获发生的区域中具有高轨道角动量和主量子数（n M*/me 38.3 和 l n 1）的“圆形”态具有微秒或更长的内部俄歇寿命
Some 3% of all antiprotons stopped in dense helium are known to survive with a mean lifetime of 3–4 s 1–6. This is due to the formation of metastable antiprotonic helium (p He) atoms 7, 8, which are neutral three-body Coulomb systems composed of a helium nucleus, an electron, and an antiproton that survive in spite of the high frequencies of collisions with ordinary helium atoms. Recently, laser spectroscopy techniques 9, 10 have enabled the direct measurement of the transition energies and lifetimes of individual states of this atom 10–19. Antiprotonic atoms are formed when one of the electrons circling an ordinary atom is replaced by an antiproton, which is captured into a highly excited state with a principal quantum number of n M*/me (M* and me are the reduced masses of the antiproton helium nucleus and electron-helium nucleus systems, respectively. These atoms typically annihilate within 1 ps, due to a variety of cascade mechanisms that quickly deexcite the antiproton into states with such small orbital angular momentum (l 0, 1,...) that their large overlap with the nucleus ensures rapid absorption. Thus antiprotonic hydrogen (p p) atoms formed in dense targets annihilate via collisional Stark processes with ordinary hydrogen atoms 20, 21, while in antiprotonic atoms heavier than helium (Z 2), the antiproton cascades down by internal Auger transitions with lifetimes of less than 1 ps 22. In the latter process, part of the binding energy and angular momentum of the antiprotonic orbit is transferred to the remaining electron; this is ejected into the continuum, while the antiproton deexcites to an energetically lower-lying ionic state.Antiprotonic helium atoms, however, appear to be unique, in that ‘‘circular’’states with high orbital angular momentum and principal quantum number in the region where initial capture takes place (n M*/me 38.3 and l n 1) have internal Auger lifetimes of microseconds or more