Within the framework of light-cone algebra, it is shown that a logarithmic divergence in the electromagnetic mass shift of a hadron arises precisely due to a mass term in the quark propagator. This divergence, therefore, can be removed by mass renormalization. The coefficient of this divergence is a scalar density which transforms as $S_3$ for the case of a nucleon. In our analysis, the gauge invariance to order $\frac{1}{q^2}$ is explicitly used.

• Received 21 September 1973

DOI:https://doi.org/10.1103/PhysRevD.8.4635