Dipole enhancement of the protonium formation cross section in antiproton collisions with excited hydrogen atoms
Dipole enhancement of the protonium formation cross section in antiproton collisions with excited hydrogen atoms
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反质子与激发氢原子碰撞中质子形成截面的偶极增强
DOI：
10.1140/epjd/e2017-80394-0
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
K Sakimoto
中科院分区：
文献类型：
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作者：
清水健二;伊藤元雄;常青;木村純一;丹下慶範, 西原遊, 瀬戸雄介, 松岡健之, 尾崎典雅;K Sakimoto
处于激发态的离子与氢原子之间存在一个有效的各向同性相互作用势，它在大间距R时表现为1/R2。由于H系统特有的能量简并，这种反常的长程部分预计将对低能碰撞过程产生重大影响。本文通过考虑反质子(p̄)与受激氢原子碰撞中质子(p̄p)的形成来解决这个问题。用半经典(量子-经典混合)方法计算了p-̄相变过程。在低碰撞能E下，形成截面远高于所谓的朗之万截面，并显示出对E-1的依赖性。这一结果与基态没有简并的氢原子的结果形成了鲜明的对比。
AbstractBetween an ion and a hydrogen (H) atom in an excited state, there exists an effectively isotropic interaction potential which behaves as 1/R2at large separationsR. The abnormal long-range part, stemming from the energy degeneracy peculiar to theHsystem, is expected to have a drastic influence on the low-energy collision processes. The present paper addresses this issue by considering protonium (p̄p) formation in antiproton (p̄) collisions with excitedHatoms. The calculation of thep̄pformation process is carried out by means of a semiclassical (quantum-classical hybrid) approach. At low collision energiesE, the formation cross section is found to be far above the so-called Langevin cross section and reveals theE-1dependence. This result is in clear contrast to that for theHatoms in the ground state with no degeneracy.Graphical abstract