Editing Beta decay (section)

==β<sup>+</sup> decay <span class="anchor" id="beta plus decay"></span>==
{{main|Positron emission}}
[[File:Electron Capture Decay.svg|thumb|The leading-order [[Feynman diagram]] for ''{{SubatomicParticle|Beta+}}''&nbsp;decay of a [[proton]] into a [[neutron]], [[positron]], and [[electron neutrino]] via an intermediate virtual [[W boson|{{SubatomicParticle|W boson+}} boson]]]]

In {{SubatomicParticle|Beta+}}&nbsp;decay, or positron emission, the weak interaction converts an atomic nucleus into a nucleus with atomic number decreased by one, while emitting a positron ({{SubatomicParticle|Positron}}) and an [[electron neutrino]] ({{SubatomicParticle|Electron neutrino}}). ''{{SubatomicParticle|Beta+}}''&nbsp;decay generally occurs in proton-rich nuclei. The generic equation is:

: {{Physics particle|TL={{mvar|A}}|BL={{mvar|Z}}|X}} → {{Physics particle|TL={{mvar|A}}|BL={{math|''Z''−1}}|X′}} + {{SubatomicParticle|Positron}} + {{math|{{SubatomicParticle|Electron Neutrino}}}}<ref name="konya74"/>
This may be considered as the decay of a proton inside the nucleus to a neutron:
:p → n + {{SubatomicParticle|Positron}} + {{math|{{SubatomicParticle|Electron Neutrino}}}}<ref name="konya74"/>

However, {{SubatomicParticle|Beta+}}&nbsp;decay cannot occur in an isolated proton because it requires energy, due to the [[mass]] of the neutron being greater than the mass of the proton. {{SubatomicParticle|Beta+}}&nbsp;decay can only happen inside nuclei when the daughter nucleus has a greater [[nuclear binding energy|binding energy]] (and therefore a lower total energy) than the mother nucleus. The difference between these energies goes into the reaction of converting a proton into a neutron, a positron, and a neutrino and into the kinetic energy of these particles. This process is opposite to negative beta decay, in that the weak interaction converts a proton into a neutron by converting an up quark into a down quark resulting in the emission of a {{SubatomicParticle|W boson+}} or the absorption of a {{SubatomicParticle|W boson-}}. When a {{SubatomicParticle|W boson+}} boson is emitted, it decays into a [[positron]] and an [[electron neutrino]]:
:{{Subatomic particle|up quark}} → {{Subatomic particle|down quark}} + {{SubatomicParticle|Positron}} + {{math|{{SubatomicParticle|Electron neutrino}}}}.