## Muons and g-2. (Lincoln)

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### Muons and g-2. (Lincoln)

`https://www.youtube.com/watch?v=UckuqHDB08I`

hyksos
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Posts: 1912
Joined: 28 Nov 2014

### Re: Muons and g-2. (Lincoln)

I liked the way that Don Lincoln expressed himself in that video, Hyksos. He made everything seem so simple and straightforward.

But did anybody else have trouble with the way the theoretical and actual measurements of a muon's gravity were portrayed? The measurements appeared to be shown as two frequency distribution curves, a blue for predicted and an orange for actual. They resembled means and distributions about the mean. But if the actual means only differed from about the sixth or seventh decimal point, I would think that the two curves would be almost sitting on top of one another with the difference being imperceptable.

I'm obviously missing something, but I would like to be educated on what I'm missing, if anyone can assist.

doogles
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Location: BRISBANE

### Re: 2B or Not 2B

In my post title, "B" is a common reference to magnetism, while "2" refers to "double".

"The magnetic moment of an electron is approximately twice what it should be in classical mechanics. The factor of two implies that the electron appears to be twice as effective in producing a magnetic moment as the corresponding classical charged body." – Wikipedia

This is also true for muons and all fundamental fermions with electric charge. It is embodied in their spin g-factors, (a.k.a. "gs" with the subscript for "spin-½"). gs is very nearly 2. A "g-factor" is obviously a factor, but in the case of gs, it's a fudge factor to force calculation to match observation.

I mention this because Lincoln surprisingly doesn't, despite its prominence in the video's title. What's going on is this. No one in physics actually knows why gs is 2. Classically, g = 1 is used merely for unit conversion. So, to avoid embarrassment, physicists talk about the minutia remaining after subtracting 2 from gs. Thus, "The physics of g – 2".

I'm not saying decimal place minutia isn't important (it does relate to the fine structure constant, α after all). It's just that it seems the proverbial cart is getting in front of the horse. So, once again, here's what's wrong (and how it's Phyxed).

The spin magnetic moment (μs) is given by an equation with proportionality constant gs over the reduced Planck constant (ħ). However, ħ = h/2pi, which means the Planck constant is reduced by dividing it by a classical rotation (i.e. 2pi radians). This is ridiculous, considering that physicists beat into the heads of poor grad students that fermion spin is NOT classical. In fact, it's experimentally proven that fermions return to their exact initial state after a double rotation (i.e. 4pi radians).

"…physical effects of the difference between the rotation of a spin-½ particle by 360° as compared with 720° have been experimentally observed in classic experiments in neutron interferometry. In particular, if a beam of spin-oriented spin-½ particles is split, and just one of the beams is rotated about the axis of its direction of motion and then recombined with the original beam, different interference effects are observed depending on the angle of rotation. In the case of rotation by 360°, cancellation effects are observed, whereas in the case of rotation by 720°, the beams are mutually reinforcing." - Wikipedia

My point is that for spin-½, the Planck constant must be reduced by 4pi rather than 2pi. Then the mysterious need for gs = 2 disappears.
It's no coincidence that 4pi radians and 4pi steradians accomplish the same resolution of the mysterious spin g-factor. It is consistent with intrinsic spin occurring in a 3-plane about a temporal axis (i.e. as chronaxial spin).

Resident Member

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Location: Times Square (T2)

### Re: Muons and g-2. (Lincoln)

If you're like me, you get bombarded by this story on all your news feeds. I guess I have to wonder, if there is this miniscule difference between the theory and measurement, then there must also be some knowledge or expectation as to what might need to change for this new data to fit with the theory or how theory might be modified to accommodate this new data. Any ideas? Links?

Dave_C
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Location: Allentown

### Re: The Tao of the Tau

Most radically, they postulate a new fundamental force.
More conservatively, analyze more data.
There have been ongoing discussions of the fine structure constant for years.

I'm suspicious that the noted deviation relates to the rest mass of the particle and subsequently its stability (implicating the weak interaction). So, I'm very interested in how the magnetic moment of muon's big brother the tauon stacks up. As these particles are short lived compared to the very stable electron, it makes such study quite challenging (t½ of tauon is one ten millionth that of muon).