transition. Thus, we can choose among 9 structures which are suitable for the two sum rules for $G_1(0)$ and $G_2(0)$.

Sum rules and numerical results
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The light-cone expansion of the correlation function is completely analogous to Section \[Proton\], even the Feynman diagrams are identical, see Fig.\[FD\]. The calculation can be simplified further if the isospin relation requiring an overall factor $(e_u-e_d)$ is taken into account. It is then sufficient to calculate only terms proportional to $e_d$, which are simpler than those proportional to $e_u$. The lengthy results for the various diagrams can be found in Appendix \[B\].

Before writing down sum rules for $G_1(0)$ and $G_2(0)$, it is advisable to identify those Lorentz structures promising the most reliable results. We will use two criteria:

1.  the structure is free of spin-1/2 contributions

2.  the structure has the highest possible power of the momentum $p$.

These demands are fulfilled by $$\mathcal{R}_{5}= \;qp \left( \gamma^{\mu}\slashed{e}\slashed{q} \gamma_5 \right) -4\left(qp\;e^{\mu}\slashed{q} \gamma_5-ep\;q^{\mu} \slashed{q}\gamma_5 \right) \mbox{ ,}$$ $$\mathcal{R}_{8}=4\left(qp\;e^{\mu}\slashed{q}\slashed{p} \gamma_5-ep\;q^{\mu}\slashed{q}\slashed{p}\gamma_5 \right) - qp \left(\gamma^{\mu}\slashed{e}\slashed{q}\slashed{p}\gamma_5 \right)\mbox{ ,}$$ and $$\mathcal{R}_{11}=q^{\mu}\slashed{e}\slashed{q}\slashed{p}\gamma_5 \mbox{ .}$$ Upon collecting the corresponding terms from Eqs.,,, and , one can easily assemble the sum rules corresponding to the three structures.

The necessary Borel transformation can 