tailieunhanh - Folding model study of the elastic alpha-alpha scattering at low energies

This result gives possible explanation of a long-standing inconsistency of the double-folding model in its study of the elastic α+α and α-nucleus scattering at low energies using the same realistic density dependent M3Y interaction. | Communications in Physics, Vol. 23, No. 4 (2013), pp. 339-365 FOLDING MODEL STUDY OF THE ELASTIC ALPHA-ALPHA SCATTERING AT LOW ENERGIES NGO HAI TAN, NGUYEN HOANG PHUC, AND DAO TIEN KHOA Institute for Nuclear Science & Technology, Vinatom 179 Hoang Quoc Viet Road, Cau Giay, Hanoi Received 04 November 2013 Accepted for publication 31 December 2013 Abstract. The folding model analysis of the elastic α+α scattering at the incident energies below the reaction threshold of MeV (in the lab system) has been done using the well-tested density dependent versions of the M3Y interaction and realistic choices for the 4 He density. Because the absorption is negligible at the energies below the reaction threshold, we were able to probe the α + α optical potential at low energies quite unambiguously and found that the α + α overlap density used to construct the density dependence of the M3Y interaction is strongly distorted by the Pauli blocking. This result gives possible explanation of a long-standing inconsistency of the double-folding model in its study of the elastic α+α and α-nucleus scattering at low energies using the same realistic density dependent M3Y interaction. I. INTRODUCTION The knowledge about the α + α interaction at low energies is of fundamental importance due, in part, to diversities of the α-cluster phenomena in nuclear physics, where one has to deal with configurations of two or more α-particles interacting with each other. Thanks to the robust, tightly bound structure of the (spin- and isospin zero) 4 He nucleus, the elastic α + α scattering cross section has been measured quite accurately during the sixties and seventies of the last century, and numerous phase-shift analyses were made based on these cross sections [1, 2]. The key quantity in an optical model (OM) study of elastic α + α scattering is the α + α optical potential (OP) that has been treated either phenomenologically [1] or evaluated microscopically from the (two-body) .