# Do the proton PDFs change much with Q?

Specifically, the second moments, do they change much from say 100 to 1000 GeV? Why or why not?

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You can check directly yourself using the Durham HEPData page, which lets you plot PDFs as a function of $x$ or $Q^2$.

At large $x = 0.1$, they're fairly constant over a range of $Q^2$.

But at small $x = 10^{-4}$, they rise quickly with $Q^2$:

This is an illustration of Bjorken scaling at large $x$ and its breaking at small $x$.

I'd also mention that the $Q^2$-dependence of the PDFs is predicted from QCD by the DGLAP equations, so you can look at those to further understand the behavior.

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