A proton is neutron bound by an electron? Where did you get that from?<p>Beta decay goes both ways[1]. In β+ decay, a proton decays into a neutron and positron, and in β− decay, a neutron decays into proton and electron. (I don&#x27;t know much physics, but I suppose there&#x27;s a limit to them decaying from one to another, and I suppose each proton&#x2F;neutron is unique in terms of its mass&#x2F;energy content.)<p>[1] See <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Beta_decay" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Beta_decay</a>