Magnetic rotation phenomenon in the dipole () bands of transitional strontium (Sr) isotopes near N=50 shell closure

Naveen Kumar; S. Kumar; S. K. Mandal; S. Saha; J. Sethi; R. Palit

doi:10.1140/epja/i2017-12212-y

EPJ

Magnetic rotation phenomenon in the dipole ( $\Delta I = 1$ ) bands of transitional strontium (Sr) isotopes near N=50 shell closure

Naveen Kumar¹^*, S. Kumar¹, S. K. Mandal¹, S. Saha², J. Sethi² and R. Palit²

¹ Department of Physics and Astrophysics, University of Delhi, 110007, Delhi, India
² Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, 400005, Mumbai, India

Received: 21 October 2015
Accepted: 23 January 2017
Published online: 14 February 2017

Abstract

The lifetime measurements were done for the transitions of the dipole ( $\Delta I=1$ ) bands in ^85,86Sr nuclei using the Doppler Shift Attenuation Method (DSAM). The high-spin states in these nuclei were populated in the ⁷⁶Ge(¹³C, 4n)⁸⁵Sr and ⁷⁶Ge(¹³C, 3n)⁸⁶Sr reactions. The B(M1) transition rates have been obtained for the states of two positive-parity dipole ( $\Delta I=1$ ) bands in the ⁸⁵Sr nucleus and one positive-parity dipole ( $\Delta I=1$ ) band in the ⁸⁶ Sr nucleus. The present results on the transition rates are important to know whether these dipole ( $\Delta I=1$ ) bands have the signatures of Magnetic Rotation (MR). In order to investigate their magnetic character, the experimental results have been compared with the calculations within the framework of hybrid Tilted-Axis-Cranking (TAC) model. On the basis of the TAC calculations, band 2 of the ⁸⁵Sr nucleus is assigned the $\pi (g_{9/2})^{2}\otimes \nu (g_{9/2})^{-1}$ configuration and shows the MR character, while for band 3, the $\pi [(g_{9/2})^{2} (f_{5/2})^{2}]\otimes \nu (g_{9/2})^{-1}$ configuration is suggested. In the case of ⁸⁶Sr nucleus, band 3 has the $\pi (g_{9/2})^{2}\otimes \nu (g_{9/2})^{-2}$ configuration below the spin $I^{\pi} = 16^{+}$ and above this spin the $\pi [(g_{9/2})^{2} (f_{5/2})^{1} (p_{1/2}/p_{3/2})^{1}] \otimes \nu (g_{9/2})^{-2}$ configuration plays an important role. The experimental B(M1) transition rates show a decreasing trend with the increase in spin and are comparable with the TAC calculations before the $I^{\pi} = 16^{+}$ .

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EPJ

Magnetic rotation phenomenon in the dipole () bands of transitional strontium (Sr) isotopes near N=50 shell closure

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Magnetic rotation phenomenon in the dipole ( $\Delta I = 1$ ) bands of transitional strontium (Sr) isotopes near N=50 shell closure