- #1

gerald V

- 63

- 3

__https://www.physicsmasterclasses.org/exercises/keyhole/en/projects/running_alphas.html__, but other sources were not able to lift my confusion either.

First, in the figure, the scales appear as quite failed. The horizontal axis clearly is meant as logarithmic, so there should not be a zero-point. The vertical scale is even more misleading, but very likely it shall be logarithmic as well. The inverse strength of electromagnetism, which is 137, can be read off quite well. For the strength of the strong force, the article gives 0,119, so its inverse is 8,40. Trying to interprete the scale, one can argue that the figure tries to show this value as well. From other sources, I got for the inverse of the weak coupling strength 31,7, and this seems to be what the figure shows.

My first question: Are the numbers 137, 8,40 and 31,7 correct or what are the correct values and what would be a good reference to look them up?

My second question: Why does this and other sources say that the weak coupling constant is about 10000 times smaller than the strong coupling constant, whereas actually the factor only is about 4? Even, the weak force is stronger than the electromagnetic force by a factor of about 4 (the inverse square of the sine of the Weinberg angle).

My third question refers to the running. I had thought that the coupling constants run to unity, whereas the figure shows that their inverses roughly run to 100. But maybe I had misunderstood this „unification“ as „becoming unity“.

Thank you very much in advance for any answer.