Observation of gamma-delayed 3 alpha breakup of the 15.11 and 12.71 MeV states in C-12
Artikel i vetenskaplig tidskrift, 2009

The reactions B-10(He-3, p alpha alpha alpha) at 4.9 MeV and B-11(He-3, d alpha alpha alpha) at 8.5 MeV have been used to investigate the gamma decay of states in C-12. By measuring the four-body final state in complete kinematics we are able to detect gamma transitions indirectly. We find gamma transitions from the 15.11 MeV state in C-12 to the 12.71, 11.83, 10.3 and 7.65 MeV states followed by their breakup into three alpha particles. The relative gamma-ray branching ratios obtained are (1.2 +/- 0.3), (0.32 +/- 0.12), (1.4 +/- 0.2) and (4.4 +/- 0.8)%, respectively, with the remaining (92.7 +/- 1.0)% of the gamma decays going to the bound states. We obtain Gamma(alpha)/Gamma = (2.8 +/- 1.2)% for the isospinforbidden alpha decay of the 15.11 MeV state. From the 12.71 MeV state we find gamma transitions to the 10.3 and 7.65 MeV states. The relative gamma-ray branching ratios are (0.9(-0.5)(+0.6)) and (2.6(-1.2)(+1.6))%, respectively, with the remaining (96.6(-1.3)(+1.7))% of the gamma decays going to the bound states. Finally. we discuss the relation between the beta decay of N-12 and B-12 to states in C-12 and the gamma decay of the 15.11 MeV analog in C-12 to the same states. (C) 2009 Elsevier B.V. All rights reserved.

decay

deduced gamma transition

unbound state

electron-scattering

light-nuclei

transitions

isovector

complete kinematics

Författare

O. S. Kirsebom

Aarhus Universitet

M. Alcorta

Consejo Superior de Investigaciones Científicas (CSIC)

M. J. G. Borge

Consejo Superior de Investigaciones Científicas (CSIC)

M. Cubero

Consejo Superior de Investigaciones Científicas (CSIC)

C. A. Diget

University of York

R. Dominguez-Reyes

Consejo Superior de Investigaciones Científicas (CSIC)

L. Fraile

Consejo Superior de Investigaciones Científicas (CSIC)

B. R. Fulton

University of York

H. O. U. Fynbo

Aarhus Universitet

D. Galaviz

Consejo Superior de Investigaciones Científicas (CSIC)

G. Garcia

Universidad Autonoma de Madrid (UAM)

S. Hyldegaard

Aarhus Universitet

H. B. Jeppesen

Aarhus Universitet

Björn Jonson

Chalmers, Teknisk fysik, Subatomär fysik

P. Joshi

University of York

M. Madurga

Consejo Superior de Investigaciones Científicas (CSIC)

A. Maria

Consejo Superior de Investigaciones Científicas (CSIC)

A. Munoz

Universidad Autonoma de Madrid (UAM)

Thomas Nilsson

Chalmers, Teknisk fysik, Subatomär fysik

Göran Hugo Nyman

Chalmers, Teknisk fysik, Subatomär fysik

D. Obradors

Consejo Superior de Investigaciones Científicas (CSIC)

A. Perea

Consejo Superior de Investigaciones Científicas (CSIC)

K. Riisager

Aarhus Universitet

Olof Tengblad

Consejo Superior de Investigaciones Científicas (CSIC)

M. Turrion

Consejo Superior de Investigaciones Científicas (CSIC)

Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics

0370-2693 (ISSN)

Vol. 680 1 44-49

Ämneskategorier (SSIF 2011)

Subatomär fysik

DOI

10.1016/j.physletb.2009.08.034

Mer information

Senast uppdaterat

2025-03-09