Hi all. Consider a UV cutoff regulator ##\Lambda## with an effective QED lagrangian ##\mathcal{L}_{\Lambda} = \bar{\psi}_{\Lambda}(i\not \partial - m_{\Lambda})\psi_{\Lambda} - \frac{1}{4}(F^{\mu\nu}_{\Lambda})^2 - e_{\Lambda}\bar{\psi}_{\Lambda}\not A_{\Lambda}\psi_{\Lambda}##. One can of course add more local operators to ##\mathcal{L}_{\Lambda}## by considering corrections from various 1-loop diagrams of the full theory. The ##\Lambda## dependence of these 1-loop corrections is easy to determine from the dimension of the operator.(adsbygoogle = window.adsbygoogle || []).push({});

But how does one systematically go about determining the dependence on the bare charge ##e## of the 1-loop corrections given the operators? For example, if I have the operator ##\bar{\psi}(\partial^2 F^{\mu\nu})\sigma_{\mu\nu}\psi## or the operator ##\bar{\psi}\partial_{\mu}F^{\mu\nu}\gamma_{\nu}\psi## or even ##\bar{\psi}\not D^3 \psi## (which are allowed by the theory since they respect gauge invariance, Lorentz invariance, and parity) how can I tell how the associated 1-loop correction will depend on ##e##?

One obvious thing to do would be to try and construct the 1-loop Feynman diagrams that these operators are generated by in the full theory and get the ##e## dependence by looking at the number of vertices but I do not have a good enough intuition to do this. For example what Feynman diagrams would generate the three operators above?

Thanks in advance!

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# Charge dependence of operators in QED renormalization

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