A.M. Mukhamedzhanov* and F.M. Nunes**
* Cyclotron Institute, Texas A & M University, College Station, TX 77843, USA
** N.S.C.L. and Department of Physics and Astronomy, Michigan State University, U.S.A.
Recibido el 29 de enero de 2005
Aceptado el 25 de mayo de 2005
]]> Abstract
We revise the standard method of extracting spectroscopic factors from transfer reactions and show the strong dependence on the single particle parameters. We propose an alternative method applicable whenever there is a significant contribution from the interior to the reaction amplitude while still being well described within Distorted Wave Born Approximation (DWBA). The energies for such reactions should be well above the Coulomb barrier. The alternative method is based on fixing the contribution of the peripheral part of the reaction amplitude, depending on the Asymptotic Normalisation Coefficient (ANC), through another independent totally peripheral reaction. Then, by combining this information with the transfer data above the barrier, one can determine the spectroscopic factor and control the uncertainty coming from the single particle parameters.
Keywords: Spectroscopic factors; ANC; DWBA analysis; transfer reactions.
Resumen
Se revisa el método standard para extraer factores espectroscópicos de reacciones de transferencia y se muestra la fuerte dependencia que el método tiene en los parámetros de partícula independiente. Proponemos un método alternativo aplicable siempre que exista una contribución significante del interior de la amplitud de reacción, además de que el fenómeno pueda describirse adecuadamente con el método aproximado de la onda distorsionada de Born (DWBA). Las energías para esta reacción deben ser dependientes del coeficiente de normalización asintótico (ANC) a través de otra reacción periférica totalmente independiente. De esta forma, al combinar esta información con los datos de transferencia sobre la barrera, es posible determinar el factor espectroscópico y controlar la incertidumbre originada en los parámetros de partícula independiente.
Descriptores: Factores espectroscópicos; ANC; análisis DWBA; Reacciones de transferencia.
PACS: 21.10.Jx; 24.10.–i; 24.50.+g; 25.40.Hs
]]> DESCARGAR ARTÍCULO EN FORMATO PDF
Acknowledgments
This work has been partially supported by the NSCL at Michigan State University, U. S. DOE under Grant No. DE–FG03–93ER40773, by NSF Award No. PHY–0140343.
References
1. L. Lapikas, I Wesseling, and R.B. Wiringa, Phys. Rev. Lett. 82 (1999) 4404. [ Links ]
2. G.J. Kramer, H.P. Blok, and L. Lapikas, Nucl. Phys. A 679 (2001) 267. [ Links ]
3. A. Navin et al., Phys. Rev. Lett. 81 (1998) 5089. [ Links ]
4. A. Gade et al., Phys. Rev. Lett. 93 (2004) 042501 and references therein. [ Links ]
5. B.A. Brown et al., Phys. Rev. C 65 (2002) 061601(R). [ Links ]
6. J. Al–Khalili and F. Nunes, J. Phys. G: Nucl. Part. Phys. 29 (2003) R89. [ Links ]
7. Xiaodong Tang et al., Phys. Rev. C 69 (2004) 055807. [ Links ]
8. N. Austern, Direct Nuclear Reaction Theories (Wiley, New York, 1970). [ Links ]
9. R.C. Johnson and P.J.R. Soper, Phys. Rev. C 1 (1970) 055807. [ Links ]
10. It is well known that one needs to go beyond DWBA to reproduce the transfer cross sections for this reaction (e.g. G.R. Satchler, Phys. Rev. C 4 (1971) 1485), thus for this example we use ADWA. In section IV DWBA is adequate and there is no need for ADWA.
11. H.J. Korner and J. P. Schiffer, Phys. Rev. Lett. 27 (1971) 1457. [ Links ]
12. S. A. Goncharov et al., Sov. J. Nucl. Phys. 35 (1982) 383. [ Links ]
13. A.M. Mukhamedzhanov and F.M. Nunes, Phys. Rev. C 72 (2005) 017602. [ Links ]
14. H. Ohnuma et al., Nucl. Phys. A 448 (1986) 205. [ Links ]
15. IP Schiffer et al., Phys. Rev. 164 (1967) 1274. [ Links ]
16. L. Trache et al., Phys. Rev. C 67 (2003) 062801. [ Links ]
17. B. Wiringa, private communication, Argonne April 2004. [ Links ]
18. H. Niewodniczanski et al., Phys. Rev. 146 (1966) 799. [ Links ]
19. G. Satchler, Phys. Rev. C (1971) 1485. [ Links ]
20. S.G. Cooper and R.S. Mackintosh, Nucl. Phys. A 511 (1990) 29. [ Links ] ]]>