Multielectron effects in capture of antiprotons and muons by helium and neon

Journal Article · Tue Aug 01 04:00:00 EDT 2000 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.62.022512· OSTI ID:20217205

Cohen, James S ^[1]

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1. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

Antiproton (p(bar sign)) and negative muon ({mu}{sup -}) captures by helium and neon atoms are treated using the fermion- molecular-dynamics method, yielding capture cross sections, initial quantum numbers, and ejected-electron energies. The calculated angular-momentum distributions tend to pile up at l=n-1 and are not well fitted by the form (2l+1)e{sup {alpha}}{sup l}, which is often assumed in experimental analyses. The residual electrons are generally left in a ''shake-up'' state. When capture is accompanied by multiple ionization, the second and later electrons escape with increasing kinetic energies, a process that is not well described as quasiadiabatic. In a 50:50 mixture of helium and neon, the calculated Ne:He capture ratios are 3.36 for p(bar sign) and 3.69 for {mu}{sup -}. The {mu}{sup -} per-atom capture probability is almost independent of the neon fraction and is in overall agreement with several {mu}{sup -} and {pi}{sup -} experiments; for p(bar sign) there is a rather strong dependence on neon fraction, but there are as yet no experiments. The possible experimental indication of a strong isotope effect on capture of {pi}{sup -} in mixtures of {sup 3}He and {sup 4}He is not supported by the present calculation. (c) 2000 The American Physical Society.

• OSTI ID: 20217205
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 62; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANTIPROTONS
CAPTURE
ELECTRON EMISSION
EXPERIMENTAL DATA
HELIUM
MUON-ATOM COLLISIONS
MUONIC ATOMS
NEON
THEORETICAL DATA