Tübingen 2003 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 37: Kernphysik/Spektroskopie V

HK 37.5: Vortrag

Donnerstag, 20. März 2003, 14:45–15:00, A

Investigation of band structures in ^172,173Lu — •Ts. Venkova^1,2, R.M. Lieder¹, W. Gast¹, W. Urban³, H.M. Jäger¹, L. Mihailescu¹, D. Bazzacco⁴, R. Menegazzo⁴, S. Lunardi⁴, C. Rossi Alvarez⁴, C. Ur⁴, T. Martinez⁴, M. Axiotis⁴, G. de Angelis⁵, D.R. Napoli⁵, and T. Rzaca-Urban³ — ¹IKP, FZ Jülich, D-52425 Jülich — ²INRNE, BAS, BG-1784 Sofia, Bulgaria — ³IEP, Univ. Warsaw, PL-00-681 Warsaw — ⁴INFN, Sezione di Padova, I-35131 Padova — ⁵INFN, LNL, I-35020 Legnaro

High-spin states in ^172,173Lu were populated at LNL through the ¹⁷⁰Er(⁷Li,xn) reaction at 51 MeV. The emitted γ-radiation was measured with the GASP array. The five known bands in ¹⁷³Lu have been extended up to much higher spins and three new band have been found. In the odd-odd nucleus ¹⁷²Lu six rotational bands consisting each of two signature sequences have been newly established. The strongest band in ¹⁷²Lu has two sequences with nine pairs showing identical transition energies within 3 keV. This band may have a π 1/2⁻[541] ⊗ ν 1/2⁻[521] configuration where the neutron is of the pseudospin singlet ν 1/2⁻[420] nature being aligned parallel and antiparallel to the rotation axis, respectively. This band represents possibly the best example of a pseudospin singlet band in normal deformed nuclei known until now. An unexpected observation is that the 1/2⁻[541] and 7/2⁺[404] bands in ¹⁷³Lu show no band crossings contrary to the corresponding bands in ¹⁷¹Lu which experience pronounced band crossings at a rotational frequency of ℏ ≈ 0.32 MeV.

The work is partly supported by the DFG grant BUL 17/7/02 and the EU contracts ERBFMGECT-980110 and HPRI-CT-1999-00083.