Direct processes in 54-MeV <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi mathvariant="normal">Li</mi></mrow><mprescripts></mprescripts><mrow></mrow><mrow><mn>7</mn></mrow><mrow></mrow><mrow></mrow></mmultiscripts></mrow></math> breakup reactions on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi mathvariant="normal">C</mi></mrow><mprescripts></mprescripts><mrow></mrow><mrow><mn>12</mn></mrow><mrow></mrow><mrow></mrow></mmultiscripts></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi mathvariant="normal">Au</mi></mrow><mprescripts></mprescripts><mrow></mrow><mrow><mn>197</mn></mrow><mrow></mrow><mrow></mrow></mmultiscripts></mrow></math> targets, and the extraction of astrophysical cross sections

S. B. Gazes; J. E. Mason; R. B. Roberts; S. G. Teichmann

doi:10.1103/PhysRevLett.68.150

Direct processes in 54-MeV ${}^{7}{Li}$ breakup reactions on ${}^{12}C$ and ${}^{197}{Au}$ targets, and the extraction of astrophysical cross sections

S. B. Gazes, J. E. Mason, R. B. Roberts, and S. G. Teichmann

Phys. Rev. Lett. 68, 150 – Published 13 January 1992

Abstract

Strong direct processes were observed for elastic breakup in 54-MeV ${}^{7}{Li}$ $+^{12}$ C ${}^{197}{Au}$ reactions. In the case of ${}^{12}C$ , the observed ${}^{7}α$ +t direct-breakup yield was significantly larger than predicted by a Coulomb-breakup calculation, indicating the importance of the nuclear field. For ${}^{197}{Au}$ , final-state interactions produced a strong distortion in the fragment energy spectra, as well as a modulation of the coincidence efficiency for different detector geometries. Such Coulomb effects are found to severely complicate the extraction of radiative-capture cross sections from direct-breakup data.