Heisenberg-Majorana nuclear forces
In March 1932 James Chadwick announced the discovery
of the neutron, after which Majorana revealed
to his friends and colleagues in Rome that he had built
a theory of light nuclei based on the quantum concept
of exchange forces. Although encouraged by Fermi to
go public with his results, Majorana’s hypercritical
judgement prevented him from doing so. True to style,
his work was not recognized until a few months later
when it was independently elaborated by Werner
Heisenberg. According to Heisenberg, the underlying nuclear forces should be interpreted in terms of nucleons exchanging spinless electrons, implicitly
assuming that the neutron was practically formed by a proton and an electron.
Majorana immediately realized this defect of the Heisenberg’s theory.
Instead, in Majorana’s view, the neutron was pictured
as a “neutral proton”, as it effectively is, and the erroneous
experimental consequences of the Heisenberg
model were quickly recognized by Heisenberg himself
and others.
This fact caused a sensation in the Rome group, and
Fermi urged Majorana, successfully, to visit Heisenberg
– who would be awarded the 1932 Nobel Prize for
Physics at the end of 1933 – in Leipzig for a six-month
period in 1933. Here, Majorana’s ability and results [8]
largely impressed Heisenberg who later, on several
occasions while discussing the “Heisenberg–Majorana”
exchange forces, only marginally mentioned his
own contribution, whereas annoyingly that of Majorana
was pointed out as if Heisenberg knew he was
indebted to his young colleague.