Mainz 1997 – wissenschaftliches Programm
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A: Atomphysik
A 8: Stöße II
A 8.1: Vortrag
Dienstag, 4. März 1997, 14:00–14:15, P104
Three-particle break-up near threshold: What happens when Wannier theory fails? — •W. Ihra, F. Mota-Furtado, and P. F. O’Mahony — Dept. of Mathematics, Royal Holloway, Univ. of London, Egham, Surrey TW20 0EX, UK
Wannier theory of three particle break-up has been successfully extended to the case of arbitrary masses and charges over recent years [1,2]. A puzzle however remains to be solved: In the case when the two wing particles have equal charges and the ratio of the charge of one of these to the charge of the third particle has the value (-4), the Wannier exponent ζ of the near threshold cross section σ∼ Eζ becomes infinite. A reaction of this type is Be3++Be4+→ 2Be4++e−. We show that the Wannier picture of ridge propagation remains valid, while the threshold law changes to the form σ∼exp[−κ/E1/6] [3]. This change occurs because the interaction of the wing particles with the third particle in the final channel is now governed by a short range potential in contrast to the generic Wannier case where it is Coulombic. We identify the threshold behavior σ∼exp[−λ/√E] obtained earlier by classical trajectory calculations [4] as the classical limit of the quantum mechanical threshold law [3].
[1] H. Klar, J. Phys. B 14, 3255 (1981)
[2] J. M. Feagin, J. Phys. B 17, 2433 (1984)
[3] W. Ihra, F. Mota-Furtado, P. F. O’Mahony, J. Phys. B, submitted (1996)
[4] M. S. Dimitrijević, P. Grujić, N. Simonović, J. Phys. B 27, 5717 (1994)