Spectroscopy at the two-proton drip line: Excited states in 158W

• Published in: Physics letters. B 2017-09, Vol.772 (C), p.703-707
• Main Authors: Joss, D.T., Page, R.D., Herzán, A., Donosa, L., Uusitalo, J., Carroll, R.J., Darby, I.G., Andgren, K., Cederwall, B., Eeckhaudt, S., Grahn, T., Greenlees, P.T., Hadinia, B., Jakobsson, U., Jones, P.M., Julin, R., Juutinen, S., Leino, M., Leppanen, A.-P., Nyman, M., O'Donnell, D., Pakarinen, J., Rahkila, P., Sandzelius, M., Sarén, J., Scholey, C., Seweryniak, D., Simpson, J., Sorri, J.
• Format: Article
• Language: English
• Subjects: Multiparticle excited states; Proton radioactivity
• ISSN: 0370-2693; 1873-2445; 1873-2445
• DOI: 10.1016/j.physletb.2017.07.031

Excited states have been identified in the heaviest known even-ZN=84 isotone 158W, which lies in a region of one-proton emitters and the two-proton drip line. The observation of γ-ray transitions feeding the ground state establishes the excitation energy of the yrast 6+ state confirming the spin-gap nature of the α-decaying 8+ isomer. The 8+ isomer is also expected to be unbound to two-proton emission but no evidence for this decay mode was observed. An upper limit for the two-proton decay branch has been deduced as b2p≤ 0.17% at the 90% confidence level. The possibility of observing two-proton emission from multiparticle isomers in nearby nuclides is considered.