C. L. Jiang

A Shorter 146Sm Half-Life Measured and Implications for 146Sm-142Nd Chronology in the Solar System

A New Lease on Half-Life Radiometric dating relies on measuring the abundance of long-lived radionuclides relative to the abundance of their radiogenic decay products—a process determined by the original radionuclides half-life. For primordial radionuclides that decay slowly, such as 146Sm decaying to 142Nd, this method provides the timing of some of the earliest processes in solar system history. Using accelerator mass spectrometry, Kinoshita et al. (p. 1614) provide a revised estimate for the 146Sm half-life of ∼68.7 million years, which is 30% shorter than the previously accepted value. This shorter half-life suggests that reductions need to be made in the estimated ages for differentiation of Earths mantle and the solidification of the Moons magma ocean and for other more recent processes. Mantle differentiation of Earth, the Moon, and Mars occurred earlier and over a shorter time scale than previously estimated. The extinct p-process nuclide 146Sm serves as an astrophysical and geochemical chronometer through measurements of isotopic anomalies of its α-decay daughter 142Nd. Based on analyses of 146Sm/147Sm α-activity and atom ratios, we determined the half-life of 146Sm to be 68 ± 7 (1σ) million years, which is shorter than the currently used value of 103 ± 5 million years. This half-life value implies a higher initial 146Sm abundance in the early solar system, (146Sm/144Sm)0 = 0.0094 ± 0.0005 (2σ), than previously estimated. Terrestrial, lunar, and martian planetary silicate mantle differentiation events dated with 146Sm-142Nd converge to a shorter time span and in general to earlier times, due to the combined effect of the new 146Sm half-life and (146Sm/144Sm)0 values.

Influence of Nuclear Structure on Sub-Barrier Hindrance in Ni + Ni Fusion

Fusion-evaporation cross sections for

Nuclear structure relevant to neutrinoless double beta decay: 76Ge and 76Se.

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Hindrance of heavy-ion fusion at extreme sub-barrier energies in open-shell colliding systems

Ni+

Stellar (n, gamma) Cross Section of ^6^2Ni

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Fission hindrance in hot 216 Th : Evaporation residue measurements

Ni have been measured down to the 10 nb level. For fusion between two open-shell nuclei, this is the first observation of a maximum in the

Observation of the one- to six-neutron transfer reactions at sub-barrier energies

S

Hindrance in the fusion ofCa48+Ca48

-factor, which signals a strong sub-barrier hindrance. A comparison with the

Indications of a shallow potential in 48 Ca+ 96 Zr fusion reactions

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Branching ratio Γ α / Γ γ of the 4.033 MeV 3 / 2 + state in 19 Ne

Ni+