Lifetime Measurement Of The 2(1)(+) State In C-20

Establishing how and when large N/Z values require modified or new theoretical tools is a major quest in nuclear physics. Here we report the first measurement of the lifetime of the 2(1)(+) state in the near-dripline nucleus C-20. The deduced value of tau(+)(21) = 9.8 +/- 2.8(stat)(-1.1)(+0.5)(syst) ps gives a reduced transition probability of B(E2; 2(1)(+) -> 0(g.s).(+)) - 7.5(-1.7)(+3.0)(stat)(-0.4)(+1.0)(syst) e(2) fm(4) in good agreement with a shell model calculation using isospin-dependent effective charges.