Transfer reactions in the investigation of light–nuclei nucleosynthesis

V. Guimarãesª, O. Camargoª, R. Lichtenthälerª, V. Scarduelliª, J.J. Kolata^b, H. Amro^c, F.D. Becchetti^c, Hao Jiang^c, E.F. Aguilera^d, D. Lizcano^d, E. Martinez–Quiroz^d, and H. Garcia^d

ª Instituto de Física, Universidade de São Paulo, P.O. Box 66318, 05389–970 São Paulo, SP, Brazil.

^b Department of Physics, University of Notre Dame, Notre Dame, Indiana, 46556, USA.

^c Department of Physics, University of Michigan, Ann Arbor, Michigan 48109–1120, USA.

^d Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18–1027, México, D.F. 11801 México.

Recibido el 27 de febrero de 2008
Aceptado el 25 de abril de 2008

Abstract

Cross sections for the ⁶Li(p,γ)⁷ Be, ⁷Li(n,γ)⁸ Li ⁸Li(n,γ)⁹ Li and ⁸Li(p,γ⁾⁹ Be capture reactions have been investigated in the framework of the potential model. The main ingredients of the potential model are the potentials used to generate the continuum and bound–state wave functions and spectroscopic factors of the corresponding bound systems. The spectroscopic factors for the ⁷Lin=⁸Li_gs, ⁸Lin=⁹Li_gs bound systems were obtained from a FR–DWBA analysis of neutron transfer reactions induced by ⁸Li radioactive beam on a ⁹Be target, while spetroscopic factor for the ⁸Lip=⁹Be_gs bound system were obained from a proton transfer reaction. From the obtained capture reaction cross section, reaction rate for the ⁸Li(n, γ)⁹Li and ⁸Li(p, γ)⁹Be direct neutron and proton capture were determined and compared with other experimental and calculated values.

Keywords: Capture reactions; transfer reactions; spectroscopic factors.

Resumen

Se hace un estudio de las secciones eficaces de las reacciones de captura para ⁶Li(p,γ)⁷ Be, ⁷Li(n,γ)⁸ Li, ⁸Li(n,γ)⁹ Li y ⁸Li(p,γ⁾⁹ y ⁸Li(p,γ)⁹Be en el marco de un modelo de potencial. Los principales ingredientes de este modelo son los potenciales usados para generar las funciones de onda del continuo y para los estados ligados así como los factores espectroscópicos de los sistemas ligados correspondientes. Los factores espectroscópicos de los sistemas ligados para ⁷Lin=⁸Li_gs, ⁸Lin=⁹Li_gs fueron obtenidos del análisis con FR–DWBA de la transferencia de un neutrón del proyectil radiactivo ⁸Li a un núcleo de ⁹Be, mientras que para el sistema ligado ⁸Lip=⁹Be_gs, los factores espectroscópicos se obtuvieron de análisis de la transferencia de un protón. De las secciones eficaces de reacciones de captura obtenidas, se determinaron las razones de reacción de captura directa y se compararon con otros valores calculados y experimentales.

Descriptores: Reacciones de captura; reacciones de transferencia; factores espectroscópicos.

PACS: 25.60.Je; 25.40.Lw; 25.70.Hi

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Acknowledgments

The authors wish to thank the Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP 2006/00629–2 and 2007/06705–5) for financial support. This work was also funded in part by the U.S. NSF under Grants No. PHY03–54828 and INT03–05347.

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