First direct measurement of ¹²C(¹²C,n)²³Mg at stellar energies

¹ Institute of Modern Physics, Chinese Academy of Science, Lanzhou, Gansu 730000, Peoples Republic of China
² Institute for Structure and Nuclear Astrophysics, Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, Indiana 46556, USA
³ Lawrence Livermore National Laboratory, Livermore, California 94550, USA
⁴ Monash Center for Astrophysics, School of Physics and Astronomy, Monash University, Victoria 3800, Australia
⁵ Department of Physics and Astronomy, Shanghai Jiao-Tong University, Center for Nuclear Astrophysics, Shanghai 200240, Peoples Republic of China
⁶ School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, USA
⁷ China Institute of Atomic Energy, Beijing 102413, Peoples Republic of China
⁸ Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklósút 15-17, H-1121 Budapest, Hungary
⁹ Department of Physics, University of Basel, Basel CH-4056, Switzerland
¹⁰ Department of Astronomy and Astrophysics, University of California, Santa Cruz, California 95064, USA

^a e-mail: xtang@impcas.ac.cn
^b e-mail: bucher3@llnl.gov

Published online: 12 February 2016

Abstract

Neutrons produced by the carbon fusion reaction ¹²C(¹²C,n)²³Mg play an important role in stellar nucleosynthesis. Past studies have shown large discrepancies between experimental data and theory, leading to an uncertain cross section extrapolation at astrophysical energies. We present the first direct measurement which extends deep into the astrophysical energy range along with a new and improved extrapolation technique based on experimental data from the mirror reaction ¹²C(¹²C,p)²³Na. The new reaction rate has been determined with a well-defined uncertainty which exceeds the precision required by astrophysics models. Using our constrained rate, we find that ¹²C(¹²C,n)²³Mg is crucial to the production of Na and Al in Pop-III Pair Instability Supernovae.