Nature of bands in A=140-180 region, a global analysis

J. B. Gupta; J. H. Hamilton

doi:10.1140/epja/i2015-15151-7

EPJ

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2023 Impact factor 2.6

Hadrons and Nuclei

Eur. Phys. J. A (2015) 51: 151
https://doi.org/10.1140/epja/i2015-15151-7

Regular Article - Theoretical Physics

Nature of $K^{\pi}=0_{2}^{+}$ bands in A=140-180 region, a global analysis

J. B. Gupta¹^* and J. H. Hamilton²

¹ Ramjas College, University of Delhi, 110007, Delhi, India
² Physics Department, Vanderbilt University, 37235, Nashville, TN, USA

^* e-mail: jbgupta2011@gmail.com

Received: 11 July 2015
Accepted: 17 October 2015
Published online: 25 November 2015

Abstract

The nature of $K^{\pi}=0_{2}^{+}$ band is analyzed in the light of the variation of the $E(0_{2}^{+})$ and $B(E2)$ values, with N and Z, for the $A=140-180$ region. The absolute $B(E2)$ strengths for the excitation of $2_{\gamma}$ and $2_{K=02}$ states are studied. Also the roles of $B(E2,0_{2}^{+}-2_{g})$ and $B(E2,0_{2}^{+}-2_{\gamma})$ are discussed. Comparison with the dynamic pairing plus quadrupole model, for all the nuclei studied here, are made on a global basis. The lack of overlap in the wave function amplitudes $A_{200}(\beta,\gamma)$ of $0_{2}^{+}$ and $A_{100}(\beta,\gamma)$ of the ground state also explains the reduced $B(E2,\beta -g)$ strength. The $B(E2,2_{\beta}\rightarrow 0_{\beta})$ is a good measure of the rotational collectivity (deformation) of the band. Shape coexistence at N = 88, 90 nuclei is reviewed. The possibility of $K^{\pi}=0_{2}^{+}$ as a $\gamma\gamma$ -vibration, when allowed by energy, in expected cases is examined. The interacting boson model predictions are also considered as required.