The α-decay of the Hoyle state in 12C: a new high-precision investigation

D. Dell‘Aquila; I. Lombardo; G. Verde; M. Vigilante; L. Acosta; C. Agodi; F. Cappuzzello; D. Carbone; M. Cavallaro; S. Cherubini; A. Cvetinovic; G. D‘Agata; L. Francalanza; G.L. Guardo; M. Gulino; I. Indelicato; M. La Cognata; L. Lamia; A. Ordine; R.G. Pizzone; S.M.R. Puglia; G.G. Rapisarda; S. Romano; G. Santagati; R. Spartà; G. Spadaccini; C. Spitaleri; A. Tumino

doi:10.1051/epjconf/201818401005

Proceedings

Open Access

EPJ Web of Conferences 184, 01005 (2018)
https://doi.org/10.1051/epjconf/201818401005

The α-decay of the Hoyle state in ¹²C: a new high-precision investigation

D. Dell‘Aquila¹^,2^*, I. Lombardo⁴, G. Verde⁴, M. Vigilante¹^,2, L. Acosta⁵, C. Agodi⁶, F. Cappuzzello⁷^,6, D. Carbone⁶, M. Cavallaro⁶, S. Cherubini⁶^,7, A. Cvetinovic⁶, G. D‘Agata⁷^,6, L. Francalanza², G.L. Guardo⁶, M. Gulino⁸^,6, I. Indelicato⁶, M. La Cognata⁶, L. Lamia⁷, A. Ordine², R.G. Pizzone⁶, S.M.R. Puglia⁶, G.G. Rapisarda⁶, S. Romano⁶, G. Santagati⁶, R. Spartà⁶, G. Spadaccini¹^,2, C. Spitaleri⁷^,6 and A. Tumino⁸^,6

¹ Dip. di Fisica "E. Pancini", Universitàdi Napoli Federico II, I-80126 Napoli, Italy
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: dellaquila@na.infn.it

Published online: 29 June 2018

Abstract

The αdecay path of the Hoyle state in ¹²C (E_x = 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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