# Error in Srednicki renormalization?

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1. Dec 16, 2015

### Higgsy

On page 164-165 of srednicki's printed version (chapter 27) on other renormalization schemes, he arrives at the equation $$m_{ph}^{2} = m^2 \left [1 \left ( +\frac{5}{12}\alpha(ln \frac{\mu^2}{m^2}) +c' \right ) + O(\alpha^2)\right]$$

But after taking a log and dividing by 2 he arrives at
$$ln[m_{ph}] = ln[m] \left [ \left ( \frac{5}{12}\alpha(ln \frac{\mu}{m}) +\frac{1}{2} c' \right ) + O(\alpha^2)\right]$$

Why is there no ln on the $$\frac{5}{12} \alpha$$ term?

2. Dec 16, 2015

### The_Duck

He is using the relation
$$\ln(1 + x) = x + O(x^2)$$
Here $x$ has an $\alpha$ in it, so the $O(x^2)$ term is absorbed into the $O(\alpha^2)$.

3. Dec 16, 2015

Thanks!