Editing Magic number (physics) (section)

==History and etymology==
[[File:Maria Goeppert-Mayer portrait.jpg|thumb|[[Maria Goeppert Mayer]]]]
While working on the [[Manhattan Project]], the German physicist [[Maria Goeppert Mayer]] became interested in the properties of nuclear fission products, such as decay energies and half-lives.<ref>{{Cite book|url=https://www.worldcat.org/oclc/255313795|title=Out of the shadows : contributions of twentieth-century women to physics|date=2006|publisher=Cambridge Univ. Pr|others=Byers, Nina.|isbn=0-521-82197-5|location=Cambridge|oclc=255313795}}</ref> In 1948, she published a body of experimental evidence for the occurrence of closed nuclear shells for nuclei with 50 or 82 protons or 50, 82, and 126 neutrons.<ref>{{Cite journal|last=Mayer|first=Maria G.|date=1948-08-01|title=On Closed Shells in Nuclei|url=https://journals.aps.org/pr/pdf/10.1103/PhysRev.74.235|journal=Physical Review|volume=74|issue=3|pages=235–239|doi=10.1103/physrev.74.235|bibcode=1948PhRv...74..235M |issn=0031-899X|url-access=subscription}}</ref> 

It had already been known that nuclei with 20 protons or neutrons were stable: that was evidenced by calculations by Hungarian-American physicist [[Eugene Wigner]], one of her colleagues in the Manhattan Project.<ref>{{Cite journal|last=Wigner|first=E.|date=1937-01-15|title=On the Consequences of the Symmetry of the Nuclear Hamiltonian on the Spectroscopy of Nuclei|url=https://link.aps.org/doi/10.1103/PhysRev.51.106|journal=Physical Review|volume=51|issue=2|pages=106–119|doi=10.1103/PhysRev.51.106|bibcode=1937PhRv...51..106W |url-access=subscription}}</ref> Two years later, in 1950, a new publication followed in which she attributed the shell closures at the magic numbers to spin-orbit coupling.<ref>{{Cite journal|last=Mayer|first=Maria Goeppert|date=1949-06-15|title=On Closed Shells in Nuclei. II|url=https://link.aps.org/doi/10.1103/PhysRev.75.1969|journal=Physical Review|volume=75|issue=12|pages=1969–1970|doi=10.1103/PhysRev.75.1969|bibcode=1949PhRv...75.1969M |url-access=subscription}}</ref> According to Steven Moszkowski, a student of Goeppert Mayer, the term "magic number" was coined by Wigner: "Wigner too believed in the [[liquid drop model]], but he recognized, from the work of Maria Mayer, the very strong evidence for the closed shells. It seemed a little like magic to him, and that is how the words 'Magic Numbers' were coined."<ref>{{Cite journal |arxiv = physics/0602050|doi = 10.1016/j.ijms.2006.01.048|title = The history of nuclidic masses and of their evaluation|journal = International Journal of Mass Spectrometry|volume = 251|issue = 2–3|pages = 85–94|year = 2006|last1 = Audi|first1 = Georges|bibcode = 2006IJMSp.251...85A| s2cid=13236732 }}</ref>

These magic numbers were the bedrock of the [[nuclear shell model]], which Mayer developed in the following years together with [[J. Hans D. Jensen|Hans Jensen]] and culminated in their shared [[Nobel Prize in Physics|1963 Nobel Prize in Physics.]]<ref>{{Cite web|title=The Nobel Prize in Physics 1963|url=https://www.nobelprize.org/prizes/physics/1963/summary/|access-date=2020-06-27|website=NobelPrize.org|language=en-US}}</ref>