Lifetime Measurement of the First Excited ${2}^{+}$ State in $^{16}\mathrm{C}$

Lifetime Measurement of the First Excited $2^{+}$ State in ${}^{16}C$

M. Wiedeking, P. Fallon, A. O. Macchiavelli, J. Gibelin, M. S. Basunia, R. M. Clark, M. Cromaz, M.-A. Deleplanque, S. Gros, H. B. Jeppesen, P. T. Lake, I.-Y. Lee, L. G. Moretto, J. Pavan, L. Phair, E. Rodriguez-Vietiez, L. A. Bernstein, D. L. Bleuel, J. T. Harke, S. R. Lesher, B. F. Lyles, and N. D. Scielzo

Phys. Rev. Lett. 100, 152501 – Published 16 April 2008

Abstract

The lifetime of the $2_{1}^{+}$ state in ${}^{16}C$ has been measured with the recoil distance method using the ${}^{9}{Be} ({}^{9}{Be}, 2 p)$ fusion-evaporation reaction at a beam energy of 40 MeV. The mean lifetime was measured to be 11.7(20) ps corresponding to a $B (E 2; 2_{1}^{+} \to 0^{+})$ value of $4.15 (73) e^{2} {fm}^{4}$ [1.73(30) W.u.], consistent with other even-even closed shell nuclei. Our result does not support an interpretation for “decoupled” valence neutrons.