Physicists Maria Goeppert Mayer and J. Hans D. Jensen develop a theory of the nucleus as composed of shells of protons and neutrons. It explains why nuclei with certain “magic numbers” of protons and ...

Drug-paired conditioned reinforcers can maintain persistent instrumental responding, thus providing a model of some aspects of long-term drug addiction. The purpose of the present study was to ...

Heavier nuclei are less stable—that’s something we all learned in school. Adding more nucleons (protons and neutrons) makes atoms more likely to break apart. It’s one reason why elements heavier than ...

Physicists have found evidence of a new “magic number” of neutrons in an unstable isotope of calcium. Using the Radioactive Ion Beam Factory at RIKEN in Japan, they have isolated calcium nuclei ...

Maria Goeppert Mayer was a physicist at Argonne who developed the nuclear shell model theory, a pivotal discovery that won her a Nobel Prize in 1963. This year marks the 75 th anniversary of the ...

Since the atomic nucleus was first proposed in 1911, physicists simply assumed it was round. But are the nuclei of atoms really round? Intuitively this shape makes sense and physicists believed it ...