Editing Ettore Majorana (section)

===First published academic papers===
[[File:Majorana Equazinfcomp.jpg|thumb|200px|Handwritten notes for the equation in infinite components]]
Majorana's first [[Academic paper|papers]] dealt with problems in [[atomic spectroscopy]]. His first paper, published in 1928, was written when he was an undergraduate and it was coauthored by Giovanni Gentile, Jr., a junior professor at the Institute of Physics in Rome. This work was an early quantitative application to atomic spectroscopy of Fermi's statistical model of atomic structure (now known as the [[Thomas–Fermi model]], due to its contemporaneous description by [[Llewellyn Thomas]]).

In this paper, Majorana and Gentile performed first-principles calculations within the context of this model that gave a good account of experimentally-observed core electron energies of [[gadolinium]] and [[uranium]], and of the fine structure splitting of [[Cesium|caesium]] lines observed in optical spectra. In 1931, Majorana published the first paper on the phenomenon of [[autoionization]] in atomic spectra, which he called "spontaneous ionization"; an independent paper in the same year, published by [[Allen Shenstone]] of [[Princeton University]], called it "auto-ionization", a name first used by [[Pierre Victor Auger|Pierre Auger]]. This name, without the hyphen, has since become the conventional term for the phenomenon.

Majorana earned his [[Laurea]] in physics at the [[University of Rome La Sapienza]] in 1929. In 1932, he published a paper in the field of atomic spectroscopy concerning the behaviour of aligned atoms in time-varying magnetic fields. This problem, also studied by [[I. I. Rabi]] and others, led to development of an important sub-branch of atomic physics, that of radio-frequency spectroscopy. In the same year, Majorana published his paper on a relativistic theory of particles with arbitrary intrinsic momentum, in which he developed and applied infinite dimensional representations of the [[Lorentz group]], and gave a theoretical basis for the mass spectrum of elementary particles. Like most of Majorana's papers, written in Italian, it languished in relative obscurity for several decades.<ref>It is discussed in detail by {{cite journal |first=D.M. |last=in |journal=Am. J. Phys. |volume=34 |pages=314–318 |year=1966 |title=Comments on a Paper by Majorana Concerning Elementary Particles|issue=4 |doi=10.1119/1.1972947 |bibcode=1966AmJPh..34..314F |citeseerx=10.1.1.522.8279 }}</ref>

Experiments in 1932 by [[Irène Joliot-Curie]] and [[Frédéric Joliot]] showed the existence of an unknown particle that they suggested was a [[gamma ray]]. Majorana was the first to interpret correctly the experiment as requiring a new particle that had a neutral charge and a mass about the same as the [[proton]]; this particle is the [[neutron]]. [[Enrico Fermi|Fermi]] advised him to write an article on the topic, but Majorana did not. [[James Chadwick]] proved the existence of the neutron by experiment later that year, and he was awarded the [[Nobel Prize]] for this discovery.<ref>{{cite web |url=http://cerncourier.com/cws/article/cern/29664 |title=Ettore Majorana: genius and mystery |publisher=[[CERN]] |website=CERN Courier|date=24 July 2006 }}</ref>

Majorana was known for not seeking credit for his discoveries, considering his work to be trivial. He wrote only nine papers in his lifetime.