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Electromagnetic quadrupole transition strength is a sensitive probe of the evolution of the structure of nuclei, particularly the competition between collectivity and magicity. We have performed a new lifetime measurement of the 21+ state of 12Be to study the interplay of these phenomena. The lifetime was measured with the Doppler Shift Attenuation Method using the γ-ray detector GRETINA. Excited states of 12Be were produced via inelastic scattering at 55 MeV/nucleon, using several different targets to control for systematic uncertainties in the stopping powers. The lifetime is determined to be τ=1.38±0.10(stat)±0.19(sys) ps, which is about half the previously reported value at twice the precision. The reduced transition strength deduced from this result is B(E2;21+→01+)=14.2±1.0(stat)±2.0(sys) e2fm4, which supports the quenching of the N=8 shell gap in 12Be. Keywords: Lifetimes, Nuclear transition probabilities, Collectivity

Symmetric collisions of massive nuclei, such as 238U + 248Cm, have been proposed as ways to make new n-rich heavy nuclei via multi-nucleon transfer (MNT) reactions. We have measured the yields of several projectile-like and target-like fragments from the reaction of 1360 MeV 204Hg + 198Pt. We find that current models for this symmetric collision (GRAZING, DNS, ImQMD) significantly underestimate the yields of these transfer products, even for small transfers. Keywords: Multi-nucleon transfer, GRAZING predictions, DNS model, Improved Quantum Molecular Dynamics model, 204Hg + 198Pt