Interference effects between direct and sequential processes in the (18O,16O) reaction

M Cavallaro,J Lubian,F Cappuzzello,R Linares,A Foti,M Niikura,J A Scarpaci,F Azaiez,A Gargano,M De Napoli,S.M Lenzi,V N Garcia,D Carbone,C Agodi,S Tropea,M Bondì,D Nicolosi,S Franchoo

doi:10.1051/epjconf/20146603017

Abstract

The 12 C( 18 O, 16 O) 14 C reaction at 84 MeV has been studied at INFN-LNS laboratory using the MAGNEX magnetic spectrometer. High resolution energy spectra and cross-section angular distributions have been measured. DWBA calculations of both direct and sequential transfer to the 14 C ground state show the important role of the interference between the two processes to describe the experimental data.

Highlights

Transfer reactions have been widely used for the exploration of the nuclear structure, thanks to their strong selectivity in selecting specific degrees of freedom of the nuclear system [1,2,3]
One can mention for example the well established connection between one-nucleon transfer cross sections and single-particle configurations of the nuclear states
The analyses present in literature required the use of arbitrary scaling factor, often called “unhappiness factor”, much larger that one and even as high as hundreds to reproduce the experimental angular distributions [4,5]

Summary

Introduction

Transfer reactions have been widely used for the exploration of the nuclear structure, thanks to their strong selectivity in selecting specific degrees of freedom of the nuclear system [1,2,3]. The extraction of structure information from two-nucleon transfer cross-sections is not straightforward, especially when dealing with heavy-ions This is due both to experimental difficulties to measure excitation energy spectra at high resolution and in a large angular range, in order to extract angular distributions, and to the complex interpretation of the data. The analyses present in literature required the use of arbitrary scaling factor, often called “unhappiness factor”, much larger that one and even as high as hundreds to reproduce the experimental angular distributions [4,5]. Taking into account the interference effects between the direct and sequential mechanisms, the agreement improves, allowing for the first time the description of heavy-ion transfer cross-section without the need of any arbitrary scaling factor

The Experiment

DWBA analysis of the angular distribution