gfactors for e,n & P??
Can anyone provide the latest gfactors for e, n & p? I could also use some explanation as to how they are applied and derived. I've already downloaded the appropriate files from the particle data site, and it does provide the most recent values for the moment data, but not their related gfactors!..Thanks in advance.

Well, you can learn doing Feynman diagrams and go at it :smile:
Here's something to get you started: http://scienceworld.wolfram.com/phys...eticRatio.html For the neutron and proton, the calculation is likely much more complicated due to the threebody structure and QCD effects. All I can say is: good luck. 
Perfect!! That link was just the kind of thing I was looking for  it gave the most current value and explained the derivation/calculation for e !
Is it too much to ask for something similiar for the neutron & proton? At least I would like to find the latest g values for both. Obviously the derivation for the proton would look the same as for the electron. However, I'm clueless as to how the neutron's value is calculated/derived  it has no charge! So, I'd appreciate even a simple explanation of the method for the neutron. Oh yeah, I have absolutely zero intention of doing any of these calculations myself  15 years on a single problem is 15 years too many!!! 
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Gyro Gyruss...
Equation (3) in Ref 1. is not correct, the corrected equation is listed: Classical Quantum Mechanics  Gyromagnetic Ratio [tex]\text{Electron Gyromagnetic Ratio}[/tex] [tex]\mu_e = \frac{q \hbar}{2m_e}[/tex] [tex]g_e = 2 \frac{\mu_e}{\hbar}[/tex] [tex]g_e = 2 \frac{q}{2m_e}[/tex] [tex]g_e = 2 \frac{q}{2m_e} = 2 \frac{\mu_e}{\hbar}[/tex] [tex]\text{Electron gfactor}[/tex] [tex]g_f = 2 \left(1 + \frac{\alpha}{2 \pi} + ... \right) = 2(1.001159652) = 2.0023193043737[/tex] [tex]g_e = g_f \frac{\mu_e}{\hbar}[/tex] [tex]\text{Proton gfactor}[/tex] [tex]g_f = 2 (1 + 1.792847338) = 2(2.792847338) = 5.585694675(57)[/tex] [tex]g_p = g_f \frac{\mu_p}{\hbar}[/tex] [tex]\text{Neutron gfactor}[/tex] [tex]g_f = 2 (0  1.91304273) = 2(1.91304273) = 3.82608545(90)[/tex] [tex]g_n = g_f \frac{\mu_n}{\hbar}[/tex] The negative Neutron gfactor indicates that its magnetic moment is opposite its spin angular momentum. There are no known theories of nuclear magnetism that explains the nuclear gfactors. Orion1 Theory: Nuclear gfactor is a measurement of nuclear magnetic susceptibility. [tex]\text{Orion1 gfactor Theory:}[/tex] [tex]\chi  \text{magnetic susceptibility}[/tex] [tex]\text{Proton gfactor}[/tex] [tex]g_f = 2(1 + \chi_p) = 2(1 + 1.792847338)[/tex] [tex]\chi_p = 1.792847338 \; \text{Paramagnetic}[/tex] [tex]\text{Neutron gfactor}[/tex] [tex]g_f = 2(1 + \chi_n) = 2(1.91304273)[/tex] [tex](1 + \chi_n) = (1.91304273)[/tex] [tex]\chi_n = 2.91304273 \; \text{Diamagnetic}[/tex] According to this Orion1 gfactor theory, unpaired Protons are paramagnetic substances, unpaired Neutrons are diamagnetic substances. Reference: http://scienceworld.wolfram.com/phys...eticRatio.html http://www.phys.au.dk/~horsdal/InApSRMenu/Gyro.html http://www.phys.au.dk/~horsdal/Graph...omagratio.gif http://hep.ucsd.edu/~branson/130/130...d/node102.html http://www.phys.ualberta.ca/~gingric...l2/node46.html http://www.fnrf.science.cmu.ac.th/tc...tant/pntoq.htm http://web.mit.edu/3.091/www/constants.html 
Orion1:
Your answer was simply superb. I am most grateful. Your theory at the end sounds plausible though I am in no position to really critique it (yet). As I'm still educating myself to this area, and as clearly you have a good deal of expertise, I would like to ask you a few more questions to shore up my understanding: 1. So the gyromagnetic ratio is really just the charge to mass ratio. Strictly speaking then, it only "really" exists for the proton and electron but not the neutron. Is this correct? 2. The gfactor relates the particles magnetic moment to the gyromagnetic ratio. It is always defined as 2*(1+anomaly). a. The (2) factor is a correction to a classical expression, which didn't take into account the particle's orbital angular momentum. Is this correct? b. The (1+anomaly) factor is purely a quantum mechanical correction. I have no clue where it comes from or even why the "1" is a "0" for the neutron. I suppose this is the trick that allows the neutron to be assigned a gyromagnetic ratio even though it has no (net) charge. Any basic guidance here would be appreciated. c. Where does the "anomaly" expression come from in standard explanations? Overall, your theory is probably the simplest answer I've ever seen given, but of course it could also be incorrect. Is there a short version of the "standard" answer to this that you've found? Perhaps also why you were motivated to go and find your own? Finally, I'll say this: it appears to me we're thinking along the same lines, i.e. magnetism is the fundamental property. 
Orion1: I have no idea what you are doing at the end; please explain?
Reality_Patrol: You seem to have a number of misconceptions; let me try to clear those up. The gyromagnetic ratio is the ratio of the measured magnetic moment to the angular momentum (here: spin) of the object in question. In classical QM, this ratio is uniquely determined from the charge and mass of the particle. However, for electrons and other elementary particles (protons and neutrons do NOT qualify as such), the observed result is slightly over twice the classical result. The Dirac theory accounts for the factor of two and attributes it to the relativistic wave equation that electrons satisfy. The slight correction (called the anomaly) is accounted by quantum electrodynamics through the interaction of the electron with the background EM field. Electric charge is the fundamental property, not magnetism. Neutrons can have a magnetic moment because they are composed of charged constituents (quarks). A firstorder calculation for proton/neutron magnetic moments based on the quark model can be found in "Introduction to Elementary Particles" by D. Griffiths, p180182. 
A good place to look for some background of the anomaly for leptons
are the papers that came after a discrepency was found for the muon anolmaly and the predictions from the Standard Model as of 2001. 2 x 1.0011 659 203 (8) experimental 2 x 1.0011 659 159 (6) theoretical Muon status Overview: http://nac21.uv.es/pdf/0208251 http://g2pc1.bu.edu/~leptonmom/talks/deRafael.pdf So there has been more interest in the muon than in the electron lately. The experiment: (Brookhaven E821) http://www.npl.uiuc.edu/~hertzog/Erice/Erice_final.ps http://www.npl.uiuc.edu/~hertzog/panic/panic_final.pdf The machine: (click on the photo to proceed) http://wwwjcsu.jesus.cam.ac.uk/~jg307/work/muon.xml Some recent theoretical work (2004) http://arxiv.org/pdf/hepph/0402206 Gives 2 x 1.0011 658 471 9 (2) theoretical which differs more instead of less. (edit: oops, This is the number with QED contributions only, so without hadronic or electroweak vacuum polarization contributions ) Some remarks: The same value for the fine structure constant is used for both the electron and the muon. I did not see any mass dependent terms in the formula for the electron (here) http://scienceworld.wolfram.com/phys...eticRatio.html but they play an important role in the calculation of the muon. (otherwise the analomy for the electron and muon would be equal) Mass dependent terms are mass ratio's and logarithms of mass ratios. These are ad hoc values and not predicted. I wonder if there is a theoretical estimate of the tau anomaly? There's no experimental value because of the very short life time of the tau lepton. Regards, Hans 
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I have not been able to find an online reference for the proton/neutron; perhaps someone else can. Quote:

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