How can a proton in a nucleus decay into neutron and positron in β+ decay if neutrons have greater mass than a proton?

Asked May 01 '22 at 00:36

Active May 01 '22 at 03:27

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I'm guessing it has something to do with mass defect/binding energy??

edited May 01 '22 at 03:27

Qmechanic

asked May 01 '22 at 00:36

Mahmodol

2

A free proton never (as far as we can tell) decays. The mass of a free proton is less than that of a neutron, so the free proton decay $p\rightarrow n+e^+ +\nu$ does not occur (also note that the positron and the neutrino also add to the total mass/energy of the decay products). However, protons inside a nuclei can decay - see this. The resulting nucleus must have a lower total energy than the original nucleus. – joseph h May 01 '22 at 01:11
Positron emission requires a nuclear transformation with at least the energy equivalent of the mass of two electrons. – Farcher May 01 '22 at 03:32

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