Lifetime of 26S and a limit for its 2p decay energy
Abstract
Unknown isotope 26S, expected to decay by two-proton (2p) emission, was studied theoretically and was 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 worked out to study a possible 2p decay branch of this nucleus. The experimental search for 26S was performed in fragmentation reactions of a 50.3 A MeV 32S beam. No events of 26S or 25P (a presumably proton-unstable subsystem of 26S) 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 26S. Analogous limits for 25P 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 26S decay a limit Q_{2p}>230 keV would follow for this nucleus. It is likely that 26S resides in the picosecond lifetime range and the further search for this isotope is prospective for the decay-in-flight technique.
Keywords
Cite
@article{arxiv.1006.4345,
title = {Lifetime of 26S and a limit for its 2p decay energy},
author = {A. S. Fomichev and I. G. Mukha and S. V. Stepantsov and L. V. Grigorenko and E. V. Litvinova and V. Chudoba and I. A. Egorova and M. S. Golovkov and A. V. Gorshkov and V. A. Gorshkov and G. Kaminski and S. A. Krupko and Yu. L. Parfenova and S. I. Sidorchuk and R. S. Slepnev and G. M. Ter-Akopian and R. Wolski and M. V. Zhukov},
journal= {arXiv preprint arXiv:1006.4345},
year = {2011}
}
Comments
15 pages, 7 figures