Negative pion capture in HD gas and in H{sub 2}+D{sub 2} gas mixtures: Resolution of the isotope puzzle

Journal Article · Tue Jun 01 04:00:00 EDT 1999 · Physical Review A

DOI:https://doi.org/10.1103/PhysRevA.59.4300· OSTI ID:341375

Cohen, J S ^[1]

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

The cross sections, initial quantum numbers, and kinetic energies for pionic atoms formed by negative pion capture in mixtures of isotopic hydrogen molecules are calculated using the fermion-molecular-dynamics (FMD) method. With these cross sections, the reduced capture ratio for a H{sub 2}+D{sub 2} mixture is found to be (P{sub p}{sup (H{sub 2}+D{sub 2})}/P{sub d}{sup (H{sub 2}+D{sub 2})})/(c{sub p}/c{sub d})=1.204, and the capture ratio for HD is found to be P{sub p}{sup (HD)}/P{sub d}{sup (HD)}=0.875. In light of these results, the {ital p}-to-d pion transfer probabilities {ital Q} are reevaluated using prior experimental data and determined to be larger than previously thought: Q=0.28 at deuterium fraction c{sub d}=0.5 and Q=0.42 as c{sub d}{r_arrow}1. The puzzling relationship of the experimental data for HD to that for H{sub 2}+D{sub 2} mixtures is explained. {copyright} {ital 1999} {ital The American Physical Society}

• OSTI ID: 341375
• Journal Information: Physical Review A, Journal Name: Physical Review A Journal Issue: 6 Vol. 59; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CROSS SECTIONS
DEUTERIUM
HYDROGEN
HYDROGEN DEUTERIDE
MOLECULAR DYNAMICS METHOD
MOLECULE-MOLECULE COLLISIONS
PION-NEUTRON INTERACTIONS
PION-PROTON INTERACTIONS
PIONIC ATOMS