Neutretto

Neutretto is the historical name for an electrically neutral meson (it was not a meson in today's sense; at that time, mesons were all particles with a mass between that of an electron and a proton ). The expression was first proposed in 1938 by Walter Heitler and Niels Arley (1911–1994) for the “neutral counterpart of the heavy electron” ( muon ), which was suspected as a hypothetical particle in the cascade decays of cosmic rays .

From around 1960, Neutretto was an alternative name for the muon neutrino . The name was based on the electron neutrino, which has long been known, since both -ino and -etto are diminutive forms of Italian .

In the modern standard model of elementary particles , the term Neutretto is no longer used.

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1. ↑ Brockhaus der Naturwissenschaften und der Technik (1951) p. 150
2. ^ Laurie Brown, Helmut Rechenberg The Origin of the Concept of Nuclear Forces , IOP, Bristol 1996, p. 213