<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article  PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="3.0" xml:lang="en" article-type="research article"><front><journal-meta><journal-id journal-id-type="publisher-id">JMP</journal-id><journal-title-group><journal-title>Journal of Modern Physics</journal-title></journal-title-group><issn pub-type="epub">2153-1196</issn><publisher><publisher-name>Scientific Research Publishing</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.4236/jmp.2015.67104</article-id><article-id pub-id-type="publisher-id">JMP-57678</article-id><article-categories><subj-group subj-group-type="heading"><subject>Articles</subject></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Physics&amp;Mathematics</subject></subj-group></article-categories><title-group><article-title>
 
 
  The Angular Momenta, Dipole Moments and Gyromagnetic Ratios of the Neutron and the Muon
 
</article-title></title-group><contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>ndreas</surname><given-names>Georgiou</given-names></name><xref ref-type="aff" rid="aff1"><sub>1</sub></xref><xref ref-type="corresp" rid="cor1"><sup>*</sup></xref></contrib></contrib-group><aff id="aff1"><label>1</label><addr-line>School of Physics, Astronomy and Mathematics, University of Hertfordshire, Hatfield, UK</addr-line></aff><author-notes><corresp id="cor1">* E-mail:<email>a.georgiou@herts.ac.uk</email></corresp></author-notes><pub-date pub-type="epub"><day>11</day><month>06</month><year>2015</year></pub-date><volume>06</volume><issue>07</issue><fpage>1004</fpage><lpage>1006</lpage><history><date date-type="received"><day>18</day>	<month>March</month>	<year>2015</year></date><date date-type="rev-recd"><day>accepted</day>	<month>27</month>	<year>June</year>	</date><date date-type="accepted"><day>30</day>	<month>June</month>	<year>2015</year></date></history><permissions><copyright-statement>&#169; Copyright  2014 by authors and Scientific Research Publishing Inc. </copyright-statement><copyright-year>2014</copyright-year><license><license-p>This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/</license-p></license></permissions><abstract><p>
 
 
  The dipole moments, angular momenta and gyromagnetic ratios of the electron and the proton were obtained earlier. In this note, we derive the corresponding expressions for the neutron and the muon. This work relies on the results obtained earlier for the angular momenta and dipole moments of rotating spherical bodies.
 
</p></abstract><kwd-group><kwd>Angular Momenta</kwd><kwd> Dipole Moments</kwd><kwd> Neutron</kwd><kwd> Muon</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>1. Introduction</title><p>The purpose of this note is to derive analytical formulae for the dipole moments, angular momenta and gyromagnetic ratios of the neutron and the muon. The background to this work is fully explained in reference [<xref ref-type="bibr" rid="scirp.57678-ref1">1</xref>] and a parallel paper on the electron and neutron [<xref ref-type="bibr" rid="scirp.57678-ref2">2</xref>] follows the same methods as presented here.</p></sec><sec id="s2"><title>2. The Electromagnetic Field Equations</title><p>We shall express the Electromagnetic Field Equations in terms of the 3-vectors representing the electric and magnetic intensities and the corresponding inductions E, H, D, B as follows:</p><disp-formula id="scirp.57678-formula788"><label>(1)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x5.png"  xlink:type="simple"/></disp-formula><p>Here, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x6.png" xlink:type="simple"/></inline-formula>are the covariant and contravariant forms of the completely anti-</p><p>symmetric permutation tensors, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x7.png" xlink:type="simple"/></inline-formula>is the determinant of the spatial metric tensor</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x8.png" xlink:type="simple"/></inline-formula>with<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x9.png" xlink:type="simple"/></inline-formula>, and <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x10.png" xlink:type="simple"/></inline-formula> is the Levi-Civita symbol.</p><p>For the details of how these expressions are derived, see [<xref ref-type="bibr" rid="scirp.57678-ref1">1</xref>] .</p></sec><sec id="s3"><title>3. The Neutron</title><p>The mass of the neutron, its classical radius, the square of the classical radius, and the vacuum speed of light, are</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x11.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x12.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x13.png" xlink:type="simple"/></inline-formula>and c.</p><p>The following quantities are required:</p><disp-formula id="scirp.57678-formula789"><label>(2)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x14.png"  xlink:type="simple"/></disp-formula><p>Associated with <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x15.png" xlink:type="simple"/></inline-formula> there is an electric charge <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x16.png" xlink:type="simple"/></inline-formula> whose numerical value is given by the first of equations (2) above [<xref ref-type="bibr" rid="scirp.57678-ref1">1</xref>] . If there is an additional charge q then the total electric charge will be<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x17.png" xlink:type="simple"/></inline-formula>. We now choose q to be<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x18.png" xlink:type="simple"/></inline-formula>, so that the total charge is zero as required in the case of the neutron. If the total electric charge is zero, the coefficient F of <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x19.png" xlink:type="simple"/></inline-formula> in the Reissner-Nordstrom solution is</p><disp-formula id="scirp.57678-formula790"><label>(3)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x20.png"  xlink:type="simple"/></disp-formula><p>where j is the angular momentum per unit mass [<xref ref-type="bibr" rid="scirp.57678-ref3">3</xref>] . On<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x21.png" xlink:type="simple"/></inline-formula>, <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x21.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x22.png" xlink:type="simple"/></inline-formula>and so on <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x21.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x22.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x23.png" xlink:type="simple"/></inline-formula> and <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x21.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x22.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x23.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x24.png" xlink:type="simple"/></inline-formula> Equation (3) becomes</p><disp-formula id="scirp.57678-formula791"><label>(4)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x25.png"  xlink:type="simple"/></disp-formula><p>which is the same as Equation (2) of [<xref ref-type="bibr" rid="scirp.57678-ref3">3</xref>] . In the case of the neutron, it follows from Equation (78) of [<xref ref-type="bibr" rid="scirp.57678-ref1">1</xref>] , that for <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x26.png" xlink:type="simple"/></inline-formula> we have</p><disp-formula id="scirp.57678-formula792"><label>(5)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x27.png"  xlink:type="simple"/></disp-formula><p>The term <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x28.png" xlink:type="simple"/></inline-formula> is negligible compared with <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x28.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x29.png" xlink:type="simple"/></inline-formula> and so Equation (5) becomes</p><disp-formula id="scirp.57678-formula793"><label>(6)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x30.png"  xlink:type="simple"/></disp-formula><p>In accordance with the results of [<xref ref-type="bibr" rid="scirp.57678-ref1">1</xref>] , the dipole moment<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x31.png" xlink:type="simple"/></inline-formula>, total angular momentum <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x31.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x32.png" xlink:type="simple"/></inline-formula> and gyromagnetic ratio <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x31.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x32.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x33.png" xlink:type="simple"/></inline-formula> are</p><disp-formula id="scirp.57678-formula794"><label>(7)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x34.png"  xlink:type="simple"/></disp-formula><p>where <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x35.png" xlink:type="simple"/></inline-formula> is given by Equation (6).</p><p>The values in (2) and Equation (6) give for <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x36.png" xlink:type="simple"/></inline-formula> and <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x36.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x37.png" xlink:type="simple"/></inline-formula></p><disp-formula id="scirp.57678-formula795"><label>(8)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x38.png"  xlink:type="simple"/></disp-formula><p>From (6) and the first of (8) we obtain <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x39.png" xlink:type="simple"/></inline-formula> and so</p><p><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x40.png" xlink:type="simple"/></inline-formula>. Since <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x40.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x41.png" xlink:type="simple"/></inline-formula> is negligible compared to 1, we may</p><p>write<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x42.png" xlink:type="simple"/></inline-formula>. From Equations (79) of [<xref ref-type="bibr" rid="scirp.57678-ref1">1</xref>] , we obtain</p><disp-formula id="scirp.57678-formula796"><graphic  xlink:href="http://html.scirp.org/file/16-7502198x43.png"  xlink:type="simple"/></disp-formula><p>Equations (7) give for <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x44.png" xlink:type="simple"/></inline-formula> and <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x44.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x45.png" xlink:type="simple"/></inline-formula></p><disp-formula id="scirp.57678-formula797"><label>(9)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x46.png"  xlink:type="simple"/></disp-formula><p>It follows that the numerical value of <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x47.png" xlink:type="simple"/></inline-formula> is</p><disp-formula id="scirp.57678-formula798"><label>(10)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x48.png"  xlink:type="simple"/></disp-formula><p>We note the important fact that this number, is precisely the value of</p><disp-formula id="scirp.57678-formula799"><label>(11)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x49.png"  xlink:type="simple"/></disp-formula></sec><sec id="s4"><title>4. The Muon</title><p>The mass <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x50.png" xlink:type="simple"/></inline-formula> and classical radius <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x50.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x51.png" xlink:type="simple"/></inline-formula> of the muon and its square are</p><disp-formula id="scirp.57678-formula800"><label>(12)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x52.png"  xlink:type="simple"/></disp-formula><p>We then obtain</p><disp-formula id="scirp.57678-formula801"><label>(13)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x53.png"  xlink:type="simple"/></disp-formula><p>For <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x54.png" xlink:type="simple"/></inline-formula> we have</p><disp-formula id="scirp.57678-formula802"><label>(14)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x55.png"  xlink:type="simple"/></disp-formula><p>If <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x56.png" xlink:type="simple"/></inline-formula> then <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x56.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x57.png" xlink:type="simple"/></inline-formula> becomes<inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x56.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x57.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x58.png" xlink:type="simple"/></inline-formula>. This is negligible compared to <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x56.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x57.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x58.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x59.png" xlink:type="simple"/></inline-formula> and so Equation (14) becomes</p><disp-formula id="scirp.57678-formula803"><label>(15)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x60.png"  xlink:type="simple"/></disp-formula><p>Equations (7) will then give</p><disp-formula id="scirp.57678-formula804"><label>(16)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x61.png"  xlink:type="simple"/></disp-formula><p>This number for the ratio <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x62.png" xlink:type="simple"/></inline-formula> is precisely the value of <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x62.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x63.png" xlink:type="simple"/></inline-formula> and so we have shown that</p><disp-formula id="scirp.57678-formula805"><label>(17)</label><graphic position="anchor" xlink:href="http://html.scirp.org/file/16-7502198x64.png"  xlink:type="simple"/></disp-formula><p>as in the case of the neutron.</p></sec><sec id="s5"><title>5. Conclusion</title><p>We have obtained the dipole moments angular momenta and gyromagnetic ratios of the neutron and the muon using the analytical formulae developed in [<xref ref-type="bibr" rid="scirp.57678-ref1">1</xref>] . The values found, are consistent with the expected values of these quantities. In particular, the ratio <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x65.png" xlink:type="simple"/></inline-formula> has the value <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x65.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x66.png" xlink:type="simple"/></inline-formula> in both the case of the neutron and in the case of the muon. We also note that <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x65.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x66.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x67.png" xlink:type="simple"/></inline-formula> has the same value as in the case of the electron and the proton [<xref ref-type="bibr" rid="scirp.57678-ref2">2</xref>] and as in the case of other rotating spherical bodies [<xref ref-type="bibr" rid="scirp.57678-ref1">1</xref>] . It is indeed remarkable that the ratio <inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x65.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x66.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x67.png" xlink:type="simple"/></inline-formula><inline-formula><inline-graphic xlink:href="http://html.scirp.org/file/16-7502198x68.png" xlink:type="simple"/></inline-formula> is first developed by us, to deal with rotating spherical bodies of arbitrary masses and radii and we apply it to the case of rotating stars. We now find that it is also valid for elementary particles, which in the classical approximation are assumed to be spherical.</p></sec></body><back><ref-list><title>References</title><ref id="scirp.57678-ref1"><label>1</label><mixed-citation publication-type="other" xlink:type="simple">Georgiou, A. (2012) Journal of Modern Physics, 3, 1301-1310. http://dx.doi.org/10.4236/jmp.2012.329168</mixed-citation></ref><ref id="scirp.57678-ref2"><label>2</label><mixed-citation publication-type="other" xlink:type="simple">Georgiou, A. (2014) Journal of Modern Physics, 5, 1254-1257.  http://dx.doi.org/10.4236/jmp.2014.514125</mixed-citation></ref><ref id="scirp.57678-ref3"><label>3</label><mixed-citation publication-type="other" xlink:type="simple">Blinder, S.M. (2003) Dirac’s Equation via General Relativity. Electromagnetic Phenomena, PACS No. 03.50.De; 14.60.C. http://www.emph.com.ua/9/pdf/blinder.pdf</mixed-citation></ref></ref-list></back></article>