Conférences et séminaires » Séminaire présenté par Paulo R.S. GOMES
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Derivation of the nuclear potential diffuseness through the study of deep sub-barrier quasi-elastic scattering.
Paulo R.S. GOMES
(Instituto de Fisica, Universidade Federal Fluminense Niterói, Rio de Janeiro, Brésil)
le Jeudi 3 mai 2007 à 16 h00
Salle de Visioconférences - Bâtiment 25
IPHC, 23 rue du Loess, Strasbourg-Cronenbourg
Knowledge of the nuclear potential is critical to describe many aspects of nuclear collisions. Elastic and inelastic scattering are sensitive to the nuclear potential in the surface region and are able to probe the surface diffuseness of the nuclear potential. Usually, diffuseness values of the order of 0.63 fm are adequate to describe scattering data. However, larger diffuseness values are required to fit recent high precision fusion excitation functions. It has recently been shown  that precise measurements of deep sub-barrier quasi-elastic excitation functions at backward angles provides a means of studying the diffuseness parameter of the Woods-Saxon nuclear potential, without any channel coupling calculations. In this work , Washiyama et al studied several systems by this method and they obtained a = 0.60 fm for the spherical systems, whereas larger diffuseness, a = 0.8 to 1.1 fm, were required to fit the data for deformed systems. More recently we analyzed quasi-elastic data previously obtained at Sao Paulo  and Buenos Aires , for spherical systems, and obtained similar results. However, none of these data had the required high precision for this study. In this talk, we will present the recently measured data (from October 2006) of deep sub-barrier quasi-elastic scattering for spherical and deformed systems, obtained in Canberra (ANU). The new data have much higher precision, and they were extended to deeper sub-barrier energies and at much more energies. The analysis of these new data leads to some conclusions different from those of ref .
 K. Washiyama, K. Hagino, M. Dasgupta, PR C71 (2006) 034607.
 D.S. Monteiro et al, submitted to PRC.
 O. Capurro et al, PRC, in press.
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