Upper Limit on the molecular resonance strengths in the ¹²C+¹²C fusion reaction

¹ Department of Physics and Joint Institute of Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556, USA
² Physics Division, Argonne National Lab, Argonne, IL 60439, USA
³ Department of Nuclear Physics, China Institute of Atomic Energy, Beijing 102413, China

^a e-mail: xtang1@nd.edu

Abstract

Carbon burning is a crucial process for a number of important astrophysical scenarios. The lowest measured energy is around E_c.m. =2.1 MeV, only partially overlapping with the energy range of astrophysical interest. The currently adopted reaction rates are based on an extrapolation which is highly uncertain because of potential resonances existing in the unmeasured energy range and the complication of the effective nuclear potential. By comparing the cross sections of the three carbon isotope fusion reactions, ¹²C+¹²C, ¹²C+¹³C and ¹³C+¹³C, we have established an upper limit on the molecular resonance strengths in ¹²C+¹²C fusion reaction. The preliminary results are presented and the impact on nuclear astrophysics is discussed.