The α-decay of the Hoyle state in 12C: a new high-precision investigation
Dip. di Fisica "E. Pancini", Universitàdi Napoli Federico II,
2 INFN-Sezione di Napoli, I-80126 Napoli, Italy
3 Institut de Physique Nucléaire, CNRS-IN2P3, Univ. Paris-Sud, UniversitéParis-Saclay Orsay Cedex, 91406 Orsay France
4 INFN - Sezione di Catania, Via S. Sofia, I-95125 Catania, Italy
5 Universidad Nacional Autónoma de México D.F., A.P. 20-364, Cd.Mx, 01000 México
6 INFN - Laboratori Nazionali del Sud, Via S. Sofia, I-95125 Catania, Italy
7 Dip. di Fisica e Astronomia, Universitàdi Catania, Via S. Sofia, I-95125 Catania, Italy
8 Facoltàdi Ingegneria ed Architettura, Università Kore, I-94100 Enna, Italy
* e-mail: email@example.com
Published online: 29 June 2018
The αdecay path of the Hoyle state in 12C (Ex = 7:654MeV) represents one ofthe most challenging questions of modern nuclear physics. Its knowledge can help in theunderstanding of cluster configurations in light nuclei and the possible existence of Bose-Einstein condensates in nuclei. In stars, it is involved in the so-called 3αprocess, wherethe 12C nucleosynthesis occurs. We studied the 14N(d; α2)12C(7:654) reaction at 10:5MeVincident energy to probe its direct decay component. We found, with a precision higherof a factor 5 than any other previous experiment, an almost total absence of direct decaysby-passing the ground state of 8Be. From our analysis, a new upper limit of such decayis found at 0:043% (95% C.L.). Astrophysical 3α process reaction rate calculations haveto be accordingly revised.
© The Authors, published by EDP Sciences, 2018
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