Eli5: how can a proton turn into a neutron in Beta Decay?

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We recently touched on the subject of radioactivity in class, and we learned about all the types of radiation an atom can emit(gama/beta-+/delta), and what their products are.

What I don’t understand is in beta- a neutron turns into 1 proton and 1 electron, but in beta+ a proton turns into a neutron, how is that possible [(n=>p+e) ==(p=>n)(e?????)]? Aren’t mater and energy subject to the laws of conservation or am I missing something? Where is the electron? Thank you in advance

In: Physics

4 Answers

Anonymous 0 Comments

As /u/polaris2acrux mentioned, there is indeed an additional (anti-)electron created during the p->n beta decay, but I’d like to mention something else with regards to this part of your post:

>Aren’t mater and energy subject to the laws of conservation or am I missing something?

If you look up the proton and neutron masses, you’ll find that the neutron is heavier than the proton. Since the electron and positron, as well as the electron neutrino and electron anti-neutrino, are equally massive, this means that there is mass gain during the p->n decay. Thus, this decay will only occur if it is possible for a bound state (such as an atom nucleus) to reach a lower energy level by this conversion. A free proton would never decay to a neutron.

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