Identification of high-spin proton configurations in $^{136}\mathrm{Ba}$ and $^{137}\mathrm{Ba}$

L. Kaya , A. Vogt , P. Reiter , C. Müller-Gatermann , A. Gargano , L. Coraggio , N. Itaco , A. Blazhev , K. Arnswald , D. Bazzacco , B. Birkenbach , A. Bracco , B. Bruyneel (1) , L. Corradi , F.C.L. Crespi , G. de Angelis , M. Droste , J. Eberth , E. Farnea , E. Fioretto , C. Fransen , A. Gadea , A. Giaz , A. Görgen (2) , A. Gottardo , K. Hadyńska-Klęk , H. Hess , R. Hetzenegger , R. Hirsch , P.R. John , J. Jolie , A. Jungclaus , W. Korten (2) , S. Leoni , L. Lewandowski , S. Lunardi , R. Menegazzo , D. Mengoni , C. Michelagnoli (3) , T. Mijatović , G. Montagnoli , D. Montanari (4) , D. Napoli , Zs. Podolyák , G. Pollarolo , F. Recchia , D. Rosiak , N. Saed-Samii , E. Şahin , M. Siciliano , F. Scarlassara , M. Seidlitz , P.A. Söderström , A.M. Stefanini , O. Stezowski (5) , S. Szilner , B. Szpak , C. Ur , J.J. Valiente-Dobón , M. Weinert , K. Wolf , K.O. Zell

1 DPHN - Département de Physique Nucléaire (ex SPhN)
2 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
3 ILL - Institut Laue-Langevin
4 IPHC - Institut Pluridisciplinaire Hubert Curien
5 IPNL - Institut de Physique Nucléaire de Lyon

The high-spin structures of Ba136 and Ba137 are investigated after multinucleon-transfer (MNT) and fusion-evaporation reactions. Ba136 is populated in a Xe136+U238 MNT reaction employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy, and in two Be9+Te130 fusion-evaporation reactions using the High-efficiency Observatory for γ-Ray Unique Spectroscopy (HORUS) at the FN tandem accelerator of the University of Cologne, Germany. Furthermore, both isotopes are populated in an elusive reaction channel in the B11+Te130 fusion-evaporation reaction utilizing the HORUS γ-ray array. The level scheme above the Jπ=10+ isomer in Ba136 is revised and extended up to an excitation energy of approximately 5.5 MeV. From the results of angular-correlation measurements, the Ex=3707- and Ex=4920-keV states are identified as the bandheads of positive- and negative-parity cascades. While the high-spin regimes of both Te132 and Xe134 are characterized by high-energy 12+→10+ transitions, the Ba136E2 ground-state band is interrupted by negative-parity states only a few hundred keV above the Jπ=10+ isomer. Furthermore, spins are established for several hitherto unassigned high-spin states in Ba137. The new results close a gap along the high-spin structure of N<82 Ba isotopes. Experimental results are compared to large-scale shell-model calculations employing the GCN50:82, Realistic SM, PQM130, and SN100PN interactions. The calculations suggest that the bandheads of the positive-parity bands in both isotopes are predominantly of proton character.

Mots clés: Nuclear Structure

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

L. Kaya, A. Vogt, P. Reiter, C. Müller-Gatermann, A. Gargano, et al.. Identification of high-spin proton configurations in $^{136}\mathrm{Ba}$ and $^{137}\mathrm{Ba}$. Phys.Rev.C, 2019, 99 (1), pp.014301. ⟨10.1103/PhysRevC.99.014301⟩. ⟨hal-01999090⟩