# What is the range of the interaction in nuclear physics?

What is the range of the interaction R, in nuclear physics?

$$R=c\Delta t$$

where $$t$$ is the time interval in which some virtual particle is exchanged.

Or, for beta decay, the range of the intercation is given by:

$$R=\frac{\hbar}{m_Wc}$$

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– Community Bot
Dec 14, 2022 at 21:49
• Dec 15, 2022 at 0:19

You just wrote down the range of interaction:

$$R = \frac{\hbar}{mc} = \frac{\hbar c}{mc^2}$$

Note that all nuclear physicists know:

$$\hbar c = 197\, {\rm Mev\cdot fm}$$

and have memorized all the masses of the light mesons, so:

$$R = \frac{197\, {\rm Mev\cdot fm}}{m_{\pi}c^2} = \frac{197\, {\rm Mev\cdot fm}}{140{\,\rm MeV}} \approx 1.4\,{\rm fm}$$

which is comparable to the proton size.

Regarding propagation times of virtual particles...that's not really a fruitful line of thinking.