High-spin states and possible “stapler” band in ${}^{115}\mathrm{In}$

High-spin states of ${}^{115}\mathrm{In}$ have been studied using the ${}^{114}\mathrm{Cd}$ (${}^7\mathrm{Li},\alpha 2\mathrm{n}$) reaction at a beam energy of 48 MeV. A total of 13 new transitions have been observed and added to the level scheme of ${}^{115}\mathrm{In}$. Most of the states in ${}^{115}\mathrm{In}$ can be interpreted in terms of the weak coupling of a $g_{9/2}$ proton hole to the core states of ${}^{116}\mathrm{Sn}$ or a $g_{7/2}$ proton to the core states of ${}^{114}\mathrm{Cd}$. A $\Delta I=1$ band with the $\pi {\left(g_{9/2}\right)}^{-1}\otimes \nu {\left(h_{11/2}\right)}^2$ configuration was suggested as an oblate band built on the “stapler” mechanism with the aid of the tilted axis cranking model based on covariant density functional theory.

Figure 1

Coincidence spectra obtained by gating on (a) the 1290.2-keV transition, and (b) the 933.7-keV transition. New transitions observed in the present work are denoted with asterisks.

Figure 2

Level scheme of ${}^{115}\mathrm{In}$. New transitions observed in the present work are denoted by asterisks.

Figure 3

Comparison of the positive-parity states based on the $7/2_1^{+}$ in ${}^{115}\mathrm{In}$ with the corresponding states in the ${}^{114}\mathrm{Cd}$ core nucleus [20].

Figure 4

Comparison of the states in structure B of ${}^{115}\mathrm{In}$ with the corresponding states in the ${}^{116}\mathrm{Sn}$ core nucleus [21, 22].

Figure 5

Total angular momentum as a function of the rotational frequency in the TAC-CDFT calculations for the structure C in ${}^{115}\mathrm{In}$ are compared with the corresponding experimental data, together with the $\pi {\left(g_{9/2}\right)}^{-1}\otimes \nu {\left(h_{11/2}\right)}^2$ bands in ${}^{113}\mathrm{In}$ [16] and ${}^{111}\mathrm{In}$ [9].

Figure 6

Compositions of the proton and neutron angular momentum vectors $J_{\pi }$ and $J_{\nu }$ as well as the total angular momentum $J_{\mathrm{tot}}=J_{\pi }+J_{\nu }$ at both rotational frequencies of 0.08 and 0.36 MeV in the TAC-CDFT calculations with the $\pi {\left(g_{9/2}\right)}^{-1}\otimes \nu {\left(h_{11/2}\right)}^2$ configuration. The inset shows a schematic view of the stapler.

Figure 7

Evolutions of deformation parameters ${\beta }_2$ and $\gamma$ driven by increasing rotational frequency in the TAC-CDFT calculations for structure C. The rotational frequencies increase from 0.08 to 0.36 MeV for the $\pi {\left(g_{9/2}\right)}^{-1}\otimes \nu {\left(h_{11/2}\right)}^2$ configuration.