Editing Nuclear magneton

{{Short description|Physical constant}}
{| class="wikitable" align="right" style="text-align:center"
|+ The value of nuclear magneton
! [[System of units]] !! Value
|-
! [[SI]]
| {{physconst|muN|ref=yes}}
|-
! [[Gaussian units|Gaussian]]
| {{val|5.05078374|e=-24|u=[[erg]]·[[Gauss (unit)|G]]{{sup|−1}}}}<ref>Since the [[2019 revision of the SI]], the Gauss is no longer exactly corresponds to 10{{sup|−4}}&nbsp;T.</ref>
|-
! eV
| {{val|3.15245125417|(98)|e=-8|u=[[electronvolt|eV]]·[[tesla (unit)|T]]{{sup|−1}}}}<ref>{{cite web |url=http://physics.nist.gov/cgi-bin/cuu/Value?munev |title=2022 CODATA Value: nuclear magneton in eV/T |publisher=[[National Institute of Standards and Technology|NIST]] |year=2022}}</ref>
|-
! MHz/T (per ''[[Planck constant|h]]'')
| {{val|7.6225932188|(24)|u=[[megahertz|MHz]]/[[tesla (unit)|T]]}}<ref>{{cite web |url=http://physics.nist.gov/cgi-bin/cuu/Value?munshhz |title=2022 CODATA Value: nuclear magneton in MHz/T: ''μ''{{sub|N}}/''h'' |publisher=[[National Institute of Standards and Technology|NIST]] |year=2022}}</ref>
|}

The '''nuclear magneton''' (symbol {{math|''μ''{{sub|N}}}}) is a [[physical constant]] of [[magnetic moment]], defined in [[SI units]] by:
<math display="block">\mu_\text{N} = {{e \hbar} \over {2 m_\text{p}}}</math>
and in [[Gaussian units|Gaussian]] [[Centimetre gram second system of units|CGS units]] by:
<math display="block">\mu_\text{N} = {{e \hbar} \over{2 m_\text{p} c}}</math>
where:
* {{math|''e''}} is the [[elementary charge]],
* {{math|''ħ''}} is the [[reduced Planck constant]],
* {{math|''m''{{sub|p}}}} is the [[proton]] [[rest mass]], and
* {{math|''c''}} is the [[speed of light]]

Its [[CODATA]] recommended value is: 
{{block indent | em = 1.5 | text = ''μ''{{sub|N}} = {{physconst|muN|ref=no}}}}
In [[Gaussian units|Gaussian]] [[Centimetre gram second system of units|CGS units]], its value can be given in convenient units as
{{block indent | em = 1.5 | text = ''μ''{{sub|N}} = {{val|0.10515446|u=[[Elementary charge|''e'']]⋅[[Femtometre|fm]]}}}}

The nuclear magneton is the natural unit for expressing magnetic dipole moments of heavy particles such as [[nucleon]]s and [[Atomic nucleus|atomic nuclei]].

Due to neutrons and protons having internal structure and not being [[Dirac particle]]s, their magnetic moments differ from {{math|''μ''{{sub|N}}}}:
: ''μ''{{sub|p}} = {{physconst|mup/muN|round=3|ref=no}}&nbsp;''μ''{{sub|N}}
: ''μ''{{sub|n}} = {{physconst|mun/muN|round=3|ref=no}}&nbsp;''μ''{{sub|N}}

The magnetic dipole moment of the electron, which is much larger as a consequence of much larger [[Mass-to-charge ratio|charge-to-mass ratio]], is usually expressed in units of the [[Bohr magneton]], which is calculated in the same fashion using the electron mass. The result is larger than {{math|''μ''{{sub|N}}}} by a factor equal to the proton-to-electron mass ratio, about 1836.

== See also ==
* [[Nucleon magnetic moment]]

== References ==
{{reflist}}

== External links ==
* {{cite web |url=https://physics.nist.gov/cgi-bin/cuu/Value?mun%7Csearch_for=nuclear+magneton |title=Nuclear magneton |publisher=[[National Institute of Standards and Technology|NIST]] |year=2014 |quote=[[CODATA]] recommended value}}.<br/>''The link contains a troublesome vertical bar; if it does not work properly try the link’s'' [http://physics.nist.gov/cgi-bin/cuu/Results?search_for=nuclear+magneton parent page] ''and select'' <u>nuclear magneton</u> ''from the displayed list''.

[[Category:Magnetism]]