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Copernicus
2018-Sep-30, 06:58 PM
Can anyone explain what the fine structure constant is at high energies? Are there different values for the fine structure constant at different energies or is it a step process like different energy levels between orbitals. Any thoughts?

Geo Kaplan
2018-Sep-30, 10:29 PM
It's a constant.

It depends on the permittivity of free space (not energy-dependent), the charge of the electron (not energy-dependent), Planck's constant (not energy-dependent) and the speed of light in free space (not energy-dependent).

It's a constant.

Copernicus
2018-Sep-30, 10:39 PM
It's a constant.

It depends on the permittivity of free space (not energy-dependent), the charge of the electron (not energy-dependent), Planck's constant (not energy-dependent) and the speed of light in free space (not energy-dependent).

It's a constant.

This is what the NIST says. https://physics.nist.gov/cuu/Constants/alpha.html It says the value is approximately 1/128 at w boson energy levels.

Geo Kaplan
2018-Oct-01, 01:02 AM
This is what the NIST says. https://physics.nist.gov/cuu/Constants/alpha.html It says the value is approximately 1/128 at w boson energy levels.

As the article you linked to says, the meaning of alpha can be modified to comport with the way coupling constants are viewed for the other fundamental interactions. I'm from an older school, which views alpha in terms of the constants given (i.e, the "long-distance" values). If you choose to adopt the view that screening at small length scales modifies the effective charge used in the traditional form of the equation for alpha, then you will get different values at different length scales. Those values presumably would span a continuum.

Copernicus
2018-Oct-01, 02:33 AM
As the article you linked to says, the meaning of alpha can be modified to comport with the way coupling constants are viewed for the other fundamental interactions. I'm from an older school, which views alpha in terms of the constants given (i.e, the "long-distance" values). If you choose to adopt the view that screening at small length scales modifies the effective charge used in the traditional form of the equation for alpha, then you will get different values at different length scales. Those values presumably would span a continuum.
That is very enlightening.