Observation and Spectroscopy of New Proton-Unbound Isotopes Ar-30 and Cl-29: An Interplay of Prompt Two-Proton and Sequential Decay
Journal article, 2015
Previously unknown isotopes Ar-30 and Cl-29 have been identified by measurement of the trajectories of their in-flight decay products S-28 + p + p and S-28 + p, respectively. The analysis of angular correlations of the fragments provided information on decay energies and the structure of the parent states. The ground states of Ar-30 and Cl-29 were found at 2.25(-0.10)(+0.15) and 1.8 +/- 0.1 MeV above the two-and one-proton thresholds, respectively. The lowest states in Ar-30 and Cl-29 point to a violation of isobaric symmetry in the structure of these unbound nuclei. The two-proton decay has been identified in a transition region between simultaneous two-proton and sequential proton emissions from the Ar-30 ground state, which is characterized by an interplay of three-body and two-body decay mechanisms. The first hint of a fine structure of the two-proton decay of Ar-30*(2(+)) has been obtained by detecting two decay branches into the ground and first-excited states of the S-28 fragment.
Author
I. Mukha
L. V. Grigorenko
X. Xu
L. Acosta
E. Casarejos
A. A. Ciemny
W. Dominik
J. Duenas-Diaz
V. Dunin
J. M. Espino
A. Estrade
F. Farinon
A. Fomichev
H. Geissel
T. A. Golubkova
A. Gorshkov
Z. Janas
G. Kaminski
O. Kiselev
R. Knobel
S. Krupko
M. Kuich
Y. A. Litvinov
G. Marquinez-Duran
I. Martel
C. Mazzocchi
C. Nociforo
A. K. Orduz
M. Pfutzner
S. Pietri
M. Pomorski
A. Prochazka
S. Rymzhanova
A. M. Sanchez-Benitez
C. Scheidenberger
P. Sharov
H. Simon
B. Sitar
R. Slepnev
M. Stanoiu
P. Strmen
I. Szarka
M. Takechi
Y. K. Tanaka
H. Weick
M. Winkler
J. S. Winfield
Mikhail Zhukov
Chalmers, Fundamental Physics
Physical Review Letters
0031-9007 (ISSN) 1079-7114 (eISSN)
Vol. 115 20 7- 202501Subject Categories
Physical Sciences
DOI
10.1103/PhysRevLett.115.202501