Editing Beta decay (section)

==β<sup>−</sup> decay <span class="anchor" id="beta minus decay"></span>==
[[Image:Beta Negative Decay.svg|thumb|right|The leading-order [[Feynman diagram]] for {{SubatomicParticle|Beta-}}&nbsp;decay of a [[neutron]] into a [[proton]], [[electron]], and [[electron antineutrino]] via a virtual [[W boson|{{SubatomicParticle|W boson-}} boson]]. For higher-order diagrams see <ref>{{Cite journal|last1=Ivanov|first1=A. N.|last2=Höllwieser|first2=R.| last3=Troitskaya|first3=N. I.|last4=Wellenzohn|first4=M.|last5=Berdnikov|first5=Ya. A.|date=2017-06-26|title=Precision theoretical analysis of neutron radiative beta decay to order O ( α 2 / π 2 )|journal=Physical Review D|language=en|volume=95| issue=11| page=113006|doi=10.1103/PhysRevD.95.113006|issn=2470-0010|arxiv=1706.08687|bibcode=2017PhRvD..95k3006I| s2cid=119103283}}</ref><ref>{{Cite journal|last1=Ivanov|first1=A. N.|last2=Höllwieser|first2=R.|last3=Troitskaya|first3=N. I.| last4=Wellenzohn|first4=M.|last5=Berdnikov|first5=Ya. A.|date=2018-11-30|title=Gauge properties of hadronic structure of nucleon in neutron radiative beta decay to order O(α/π) in standard ''V – A'' effective theory with QED and linear sigma model of strong low-energy interactions|journal=International Journal of Modern Physics A|language=en|volume=33|issue=33|page=1850199| doi=10.1142/S0217751X18501993| issn=0217-751X|arxiv=1805.09702|bibcode=2018IJMPA..3350199I |s2cid=119088802}}</ref>]]
In {{SubatomicParticle|Beta-}}&nbsp;decay, the [[weak interaction]] converts an [[atomic nucleus]] into a nucleus with [[atomic number]] increased by one, while emitting an electron ({{SubatomicParticle|Electron|link=yes}}) and an electron [[Neutrino#Antineutrinos|antineutrino]] ({{SubatomicParticle|Electron antineutrino}}). {{SubatomicParticle|Beta-}}&nbsp;decay generally occurs in neutron-rich nuclei.<ref name=Loveland>{{cite book
 |last=Loveland |first=W. D.
 |year=2005
 |title=Modern Nuclear Chemistry
 |url=https://books.google.com/books?id=ZAHJkrJlwbYC&pg=PA233
 |page=232
 |publisher=[[John Wiley & Sons|Wiley]]
 |isbn=978-0-471-11532-8
}}</ref> The generic equation is:

: {{Physics particle|TL={{mvar|A}}|BL={{mvar|Z}}|X}} → {{Physics particle|TL={{mvar|A}}|BL={{math|''Z''+1}}|X′}} + {{SubatomicParticle|Electron}} + {{math|{{SubatomicParticle|Electron Antineutrino}}}}<ref name="konya74"/>
where {{mvar|A}} and {{mvar|Z}} are the [[mass number]] and [[atomic number]]<!-- "charge" is linked from another place. "mass number" is paired with "atomic number" --> of the decaying nucleus, and X and X′ are the initial and final elements, respectively.

Another example is when the [[free neutron]] ({{nuclide|neutronium|1}}) decays by {{SubatomicParticle|Beta-}}&nbsp;decay into a proton ({{SubatomicParticle|Proton}}):
: {{SubatomicParticle|Neutron}} → {{SubatomicParticle|Proton}} + {{SubatomicParticle|Electron}} + {{math|{{SubatomicParticle|Electron Antineutrino}}}}.
<!-- never use <math> for it, because symbols of particles may not be italicized! -->

At the [[fundamental particle|fundamental]] level (as depicted in the [[Feynman diagram]] on the right), this is caused by the conversion of the negatively charged ({{math|−{{sfrac|1|3}} [[elementary charge|e]]}}) down quark to the positively charged ({{math|+{{sfrac|2|3}} e}}) up quark, which is promoted by a virtual [[W boson|{{SubatomicParticle|W boson-}} boson]]; the {{SubatomicParticle|W boson-}} boson subsequently decays into an electron and an electron antineutrino:
:{{Subatomic particle|down quark}} → {{Subatomic particle|up quark}} + {{SubatomicParticle|Electron}} + {{math|{{SubatomicParticle|Electron Antineutrino}}}}.