 The neutrino was a subatomic particle first proposed theoretically by Wolfgang Pauli on December 4 , 1930 , to explain undetected energy that escaped during beta decay when neutron decayed into a proton and an electron so that the law of conservation of energy was not violated . Enrico Fermi renamed it the neutrino , Italian for " little neutral one " , and in 1934 , proposed his theory of beta decay which explained that the electrons emitted from the nucleus were created by the decay of a neutron into a proton , an electron , and a neutrino : 
 The neutrino was a subatomic particle first proposed theoretically by Wolfgang Pauli on December 4 , 1930 , to explain undetected energy <a href='null_relcl' title='1'><mark>that</mark></a>escaped during beta decay when neutron decayed into a proton and an electron so that the law of conservation of energy was not violated . Enrico Fermi renamed it the neutrino , Italian for " little neutral one " , and in 1934 , proposed his theory of beta decay which explained that the electrons emitted from the nucleus <a href='uninflect' title='2'><mark>were</mark></a> created by the decay of a neutron into a proton , an electron , and a neutrino : 
The neutrino was a subatomic particle first proposed theoretically by Wolfgang Pauli on December 4 , 1930 , to explain undetected energy escaped durin beta decay when neutron decayed into a proton and an electron so dat the law of conservation of energy was not violated . Enrico Fermi renamed it da neutrino , Italian for " little neutral one " , and in 1934 , proposed his theory of beta decay which explained tdatthe electrons emitted from tdanucleus was created by thdaecay of a neutron into a proton , an electron , and a neutrino :