Evidence for a change of structure in the heavy mercury isotopes around 200Hg

High-resolution study of excited0+states in200Hg and202Hg

“…[23] and a 0 + assignment for a state at 1901-keV excitation energy in Ref. [24]. In both cases, we do not observe the typical forward-peaking signature for the expected L = 0 transfer and measured R(5/17.5) = 1.10 (8) Fig.…”

“…It has been associated with an oblate single particle energy gap [24] but other explanations such as mixing or coexistence cannot be ruled out. We note that the twoneutron separation energy S 2n shows at most a weak anomaly (visible in the differential δS 2n ) [32,33].…”

Investigation of0+states in198Hg after two-neutron pickup

“…Besides the ground state, we observe three more states showing this typical L = 0 transfer characteristic. Two of these states, the 0 + states at 1401 and 1780 keV, are already known and assigned as 0 + states [15,16]. In addition, we found a new, weakly populated state at 1646 keV.…”

“…In Ref. [16], a further 0 + state was assigned at 1550 keV, as well, based on a (p, t) transfer experiment. We observe a state at 1549 keV, but our much higher resolution data does not support this 0 + assignment since R(5/17.5) ≈ 0.4.…”

Investigation of 0+states in mercury isotopes after two-neutron transfer

“…In Ref. [24], the enhanced 0 + 2 cross section in 200 Hg has been associated with an oblate single particle energy gap, but other explanations like mixing or coexistence cannot be ruled out. Another indicator for structural changes, the two-neutron separation energy S 2n (or the differential δS 2n ), shows at most a weak anomaly [25,26].…”