[more_original]

At first, I thought the title was a mistake, as the letter speaks of 'neutrons' throughout. But it turns out that the term 'neutrino' came only later:

'Pauli earlier (in 1930) had used the term "neutron" for both the neutral particle that conserved energy in beta decay, and a presumed neutral particle in the nucleus, and initially did not consider these two neutral particles as distinct from each other'

(from https://en.wikipedia.org/wiki/Neutrino)

[KIFulgore]

I thought the HN headline was incorrect until I read Pauli was looking for a particle of ~0.01 proton mass (neutrons and protons are about the same mass).

[mabbo]

Thank you, I too was confused by this