Direct Observation of the ${4}^{+}$-to-${2}^{+}$ Gamma Transition in $^{8}\mathrm{Be}$

Direct Observation of the $4^{+}$ -to- $2^{+}$ Gamma Transition in ${}^{8}{Be}$

V. M. Datar, Suresh Kumar, D. R. Chakrabarty, V. Nanal, E. T. Mirgule, A. Mitra, and H. H. Oza

Phys. Rev. Lett. 94, 122502 – Published 1 April 2005; Erratum Phys. Rev. Lett. 94, 139902 (2005)

Abstract

Electromagnetic transition rates provide an important test for nuclear structure models. The nucleus ${}^{8}{Be}$ exhibits a pronounced alpha-cluster structure and is a building block for more complex cluster nuclei. Here we report on the first observation of the gamma transition between the $4^{+}$ and $2^{+}$ states of ${}^{8}{Be}$ in the ${}^{4}{He} + {}^{4}{He}$ reaction. The measured on-resonance cross section of $165 \pm 54 nb$ leads to a $B (E 2)$ of $25 \pm 8 e^{2} f m^{4}$ , in good agreement with alpha-cluster models and sophisticated ab initio structure calculations.