A new high-precision upper limit of direct α-decays from the Hoyle state in 12C

Autor: Dell’Aquila D., Lombardo I., Verde G., Vigilante M., Acosta L., Agodi C., Cappuzzello F., Carbone D., Cavallaro M., Cherubini S., Cvetinovic A., D’Agata G., Francalanza L., Guardo G.L., Gulino M., Indelicato I., La Cognata M., Lamia L., Ordine A., Pizzone R.G., Puglia S.M.R., Rapisarda G.G., Romano S., Santagati G., Spartà R., Spadaccini G., Spitaleri C., Tumino A.
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: EPJ Web of Conferences, Vol 165, p 01020 (2017)
Druh dokumentu: article
ISSN: 2100-014X
DOI: 10.1051/epjconf/201716501020
Popis: The Hoyle state in 12C(Ex = 7.654MeV) is characterized by a pronounced 3α cluster configuration. It is involved in the so-called 3α process in stars, that is responsible of 12C nucleosynthesis. We studied the decay path of the Hoyle state by using the 14N(d, α2)12C(7.654) reaction at 10.5MeV incident energy. We found, with a precision higher of a factor 5 than any other previous experiment, an almost total absence of direct decays by-passing the ground state of 8Be. A new upper limit of such a decay width is placed at 0.043% (95% C.L.). Astrophysical 3α process reaction rate calculations have to be consequently revised.
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