2010/06/30 by A. S. Fomichev, A. S. FOMICHEV, А. С. Фомичев +38 · 1 citation
Physics and Astronomy · #Astronomical and nuclear sciences #Atomic and Molecular Physics #Nuclear physics research studies #nucl-ex
paper · pdf · doi:10.1142/s0218301311018216
published as Int.J.Mod.Phys.E20:1491-1508,2011 · 15 pages, 7 figures
arxiv created 2010/08/05 · arxiv updated 2011/07/15
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 T1/2<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 Q2p>640 keV for 26S. Analogous limits for 25P are found as T1/2<38 ns and Qp>110 keV. In the case that the one-proton emission is the main branch of the 26S decay a limit Q2p>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.