Paulis Solution to Preserve Conservation of Energy

The conservation of energy was deeply accepted by all scientists at the start of the twentieth century. It was found by mass spectrometry that the atomic weights 

It was observed that in the case of the -decay the first law, i.e., the conservation of energy, is violated. Pauli was so much convinced in the correctness of the conservation of energy that he postulated the existence of a hitherto unknown particle. This particle should take away the missing energy. An English translation of Pauli s famous letter, given subsequently, can be found elsewhere [4]. 

Physikeilisches Institut der Eidg. Techmschen Hochschule Zurich 

Ojfener Brief an die Gruppe der Radioaktiven bei der Gau-Vereinigung zu Tubingen liebe Radioeiktive Damen und Herren 

Das kontinuierliche /3-Spektrum ware dann verstandlich unter der Annahme, daB beim /3-Zerfall mit dem Elektron jeweils noch ein Neutron emittiert wird, derart, daB die Summe der Energien von Neutron und Elektron konstant ist... 

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