High Spin Physics 2001 - Abstract 028

High Spin Physics 2001, Warsaw, February 6-10, 2001

Abstract No: 028

Submitted on: 3 Jan 2001, 11:20 GMT

Title: Investigation of the $K^{\pi}$ = 8^- isomers in N=74 isotones on beam of the Warsaw Cyclotron

Author(s): T. Morek,¹ J. Srebrny,¹ Ch.Droste,¹ M. Kowalczyk,¹ T. Rzaca-Urban,¹ K. Starosta,¹ W. Urban,¹ R. Kaczarowski,² E. Ruchowska,² M. Kisielinski,³ A. Kordyasz,³ J. Kownacki,³ M. Palacz,³ E. Weso $\l$ owski,³ M. Wolinska,³ W. Gast,⁴ R.M. Lieder,⁴ P. Bednarczyk,⁵ W. Meczynski,⁵ J. Styczen,⁵

Affiliation(s): ¹Nuclear Physics Division, IEP, Warsaw University, Poland, ²The Andrzej So $\l$ tan Institute for Nuclear Studies, Swierk, Poland, ³Heavy Ion Laboratory, Warsaw University, Poland, ⁴Institut für Kernphysik, Forschungszentrum Jülich, Germany, ⁵The Niewodniczanski Institute of Nuclear Physics, Kraków,Poland

The decay of the $K^{\pi}$ = 8^- isomers in ¹³²Ce and ¹³⁴Nd have been investigated on the beam of the Warsaw Cyclotron using OSIRIS array. Reactions ¹²⁰Sn(¹⁶O,4n)¹³²Ce and ¹¹⁸Sn(²⁰Ne,4n)¹³⁴Nd were used.

For ^132mCe a half-life of 9.4 $\pm$ 0.3 ms was determined. Two new decay paths have been found in the deexcitation of this isomer. The hindrance factors for the E1, M2 and E3 transitions deexciting the isomer have been determined [1]. The decay properties of the 8^- isomers in the N=74 isotones are discussed. A band mixing mechanism involving the ground state band and s-band seems to be responsible for the behaviour of the reduced hindrance factors of the E1 transitions deexciting the $K^{\pi}$ =8^- isomers in these isotones.

A K-mixing, characteristic for the axially asymmetric nuclei, may account for the reduced hindrance factors $f_3 \approx 6.5$ of the E3 transition to the 5 $_{\gamma }^{+}$ states in ¹³⁰Ba and ¹³²Ce. Similar E3 decay of the 410 $\mu$ s isomeric state in ^134mNd has not been observed. However, we were able to determine that in this case the reduced hindrance factor $f_3\geq 9$ .

Bibliography

1: T. Morek et. al, Phys.Rev C63 (2001), in print.

$\fbox{ Preferred presentation of the contribution: in the oral session. }$

High Spin Conference
2001-01-04

Abstract No:	028
Submitted on:	3 Jan 2001, 11:20 GMT
Title:	Investigation of the $K^{\pi}$ = 8^- isomers in N=74 isotones on beam of the Warsaw Cyclotron
Author(s):	T. Morek,¹ J. Srebrny,¹ Ch.Droste,¹ M. Kowalczyk,¹ T. Rzaca-Urban,¹ K. Starosta,¹ W. Urban,¹ R. Kaczarowski,² E. Ruchowska,² M. Kisielinski,³ A. Kordyasz,³ J. Kownacki,³ M. Palacz,³ E. Weso $\l$ owski,³ M. Wolinska,³ W. Gast,⁴ R.M. Lieder,⁴ P. Bednarczyk,⁵ W. Meczynski,⁵ J. Styczen,⁵
Affiliation(s):	¹Nuclear Physics Division, IEP, Warsaw University, Poland, ²The Andrzej So $\l$ tan Institute for Nuclear Studies, Swierk, Poland, ³Heavy Ion Laboratory, Warsaw University, Poland, ⁴Institut für Kernphysik, Forschungszentrum Jülich, Germany, ⁵The Niewodniczanski Institute of Nuclear Physics, Kraków,Poland