Eur. Phys. J. A (2007) 31: 303-317
https://doi.org/10.1140/epja/i2006-10298-x

Regular Article - Nuclear Structure and Reactions

Structure of low-lying ¹²C resonances

¹ Institut for Fysik og Astronomi, Aarhus Universitet, DK-8000, Aarhus C, Denmark
² Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientıficas, Serrano 123, E-28006, Madrid, Spain

Received: 28 November 2006
Accepted: 5 March 2007
Published online: 23 March 2007

Abstract

The hyperspherical adiabatic expansion is combined with complex scaling and used to calculate low-lying nuclear resonances of ¹²C in the 3α model. We use Ali-Bodmer potentials and compare results for other potentials α-α with similar ⁸Be properties. A three-body potential is used to adjust the ¹²C resonance positions to desired values extending the applicability of the method to many-body systems decaying into three α-particles. For natural choices of three-body potentials we find 14 resonances below the proton separation threshold, i.e. two 0⁺, three 2⁺, two 4⁺, one of each of 1^±, 2^-, 3^±, 4^-, and 6⁺. The partial-wave decomposition of each resonance is calculated as a function of the hyperradius. Strong variation is found from small to large distance. The connection to previous experimental and theoretical results is discussed and agreements as well as disagreements are emphasized.