Münster 2002 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 18: Nuclear and Particle Astrophysics II
HK 18.7: Vortrag
Dienstag, 12. März 2002, 18:30–18:45, C
The Trojan-Horse Method in Nuclear Astrophysics — •Stefan Typel1 und Hermann Wolter2 — 1NSCL/Michigan State University, USA — 2University of Munich, Germany
The Trojan-Horse method (THM) is an indirect way to determine the energy dependence of nuclear cross sections at the very low energies of astrophysical interest. In this method the Coulomb barrier in the astrophysical reaction is effectively reduced by adding a spectator to one of the participating nuclei and by studying the breakup of the final three-body system in the particular region of the phase space where the momentum transfer to the spectator is small. In the plane-wave impulse approximation the cross section is a product of three factors: (1) a kinematical factor, (2) a momentum distribution, (3) an off-shell two-body cross section. The relation of the latter to the on-shell cross section was previously assumed in a heuristic approximation. We present inprovements in the theoretical description of the process starting from a distorted wave Born approximation. It yields a simple connection between the on-shell and off-shell cross sections. Applications of the THM in recent experiments, e.g. 7Li(p,α)α and 6Li(d,α)α, are discussed.