Lifetime of 26S and a Limit for its 2p Decay Energy

A. S. Fomichev; I. G. Mukha; S. V. Stepantsov; L. V. Grigorenko; E. V. Litvinova; V. Chudoba; I. A. Egorova; M. S. Golovkov; A. V. Gorshkov; V. A. Gorshkov; G. Kaminski; S. A. Krupko; Y. L. Parfenova; S. I. Sidorchuk; R. S. Slepnev; G. M. Ter-Akopian; R. Wolski; Mikhail Zhukov

doi:10.1142/s0218301311018216

Lifetime of 26S and a Limit for its 2p Decay Energy
Journal article, 2011

The unknown isotope (26)S, expected to decay by two-proton (2p) emission, was studied theoretically and searched experimentally. The structure of this nucleus was examined within the relativistic mean field (RMF) approach. A method for taking into account the many-body structure in the three-body decay calculations was developed. The results of the RMF calculations were used as an input for the three-cluster decay model optimized for the study of a possible 2p decay branch of this nucleus. The experimental search for (26)S was performed by fragmentation of a 50.3 A MeV (32)S beam. No events of a particles table (26)S or (25)P (a presumably proton-unstable subsystem of (26)S) were observed. Based on the obtained production systematics, an upper half-life limit of T(1/2) < 79 ns was established from the time-of-flight through the fragment separator. Together with the theoretical lifetime estimates for two-proton decay, this gives a decay energy limit of Q(2p) > 640 keV for (26)S. Analogous limits for (25)P are found as T(1/2) < 38 ns and Q(p) > 110 keV. In the case that the one-proton emission is the main branch of the (26)S decay, a limit Q(2p) > 230 keV would follow for this nucleus. According to these limits, it is likely that (26)S resides in the picosecond life time range

mean-field-theory

fe-45

nuclear energy

be-6

halos

light-nuclei

radioactivity

shell

2-proton decay

neutron

Properties of nuclei

proton

drip lines