Neutrino: The Particle that Shouldn’t Exist


Professor Roberto Trotta

Roberto Trotta is Visiting Gresham Professor of Cosmology and Professor of Astrostatistics at Imperial College, London.

Astrostatistics is a discipline which spans astrophysics, statistical analysis and data mining. It is used to process the vast amount of data produced by automated scanning of the cosmos, to characterize complex datasets, and to link astronomical data to astrophysical theory.

For more information about him, please visit his website:

Roberto Trotta’s lecture series are as follows:

2020/21 The Unexpected Universe

2019/20 The Nature of Reality

All lectures by the Visiting Professor of Cosmology can be accessed here.

In 1930, the great physicist Wolfgang Pauli did something that “no theorist should ever do”: he invented a new particle that he thought nobody could ever detect in order to save the principle of energy conservation in certain radioactive decays he was studying. Pauli’s impossible particle turned out to be real: the neutrino, a particle that one of its discoverers called “the most tiny quantity of reality ever imagined by a human being”.

This lecture (link above) charted the fascinating history and science of neutrinos, from their discovery in 1956 to the role they played in understanding solar physics. Neutrinos are today hunted for in the depths of the Antarctic ice cap, shot through the crust of the Earth and observed in huge water tanks under miles of rock. They are revealing the physics of distant supernovae, helping understand dark matter and might hold the key to the Big Bang itself.

Wolfgang Ernst Pauli (25 April 1900 – 15 December 1958) was an Austrian (and later American / Swiss) theoretical physicist and one of the pioneers of quantum physics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics for his “decisive contribution through his discovery of a new law of Nature, the exclusion principle or Pauli principle”. The discovery involved spin theory, which is the basis of a theory of the structure of matter.

A neutrino is a fermion (an elementary particle with spin of 1/2) that interacts only via the weak subatomic force and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was long thought to be zero. The mass of the neutrino is much smaller than that of the other known elementary particles. The weak force has a very short range, the gravitational interaction is extremely weak, and neutrinos do not participate in the strong interaction. Thus, neutrinos typically pass through normal matter unimpeded and undetected.


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