## Electromagnetic transition from the 4$^+$ to 2$^+$ resonance in $^8$Be measured via the radiative capture in $^4$He+$^4$He    [PDF]

V. M. Datar, D. R. Chakrabarty, Suresh Kumar, V. Nanal, S. Pastore, R. B. Wiringa, S. P. Behera, A. Chatterjee, D. Jenkins, C. J. Lister, E. T. Mirgule, A. Mitra, R. G. Pillay, K. Ramachandran, O. J. Roberts, P. C. Rout, A. Shrivastava, P. Sugathan
An earlier measurement on the 4$^+$ to 2$^+$ radiative transition in $^8$Be provided the first electromagnetic signature of its dumbbell-like shape. However, the large uncertainty in the measured cross section does not allow a stringent test of nuclear structure models. The present paper reports a more elaborate and precise measurement for this transition, via the radiative capture in the $^4$He+$^4$He reaction, improving the accuracy by about a factor of three. The {\it ab initio} calculations of the radiative transition strength with improved three-nucleon forces are also presented. The experimental results are compared with the predictions of the alpha cluster model and {\it ab initio} calculations.
View original: http://arxiv.org/abs/1305.1094