changing matrix elements in partially twisted QCD, we briefly recall how the latter can be determined at continuous momentum transfer from lattice correlators. To implement the twisted boundary conditions one uses interpolating fields for the hadrons built of the $\Qt$ fields that are periodic but coupled to the background field $B_\mu$. For example, let us denote neutron and proton interpolating fields constructed in this way as $\tilde{\cN} (\bm{x},t)$ and $\tilde{\cP}(\bm{x},t)$. One then calculates the correlation function $$\label{eq:corr}
C(t,t') 
= 
\sum_{\bm{x}, \bm{x'}} 
e^{-i \bm{P}\cdot \bm{x'}} 
\langle 0 | \cPt(\bm{x},t) \cOt^+ (\bm{x'},t') \ol \cNt (\bm{0},0) | 0 \rangle
,$$ where $\cOt^+$ is the valence isospin raising operator $$\cOt^+ (\bm{x},t) = \overline{\tilde{u}} (\bm{x},t) \,  \tilde{\Gamma} \, \tilde{d} (\bm{x},t)
,$$ and the Dirac and Lorentz structure $\tilde{\Gamma}$ is arbitrary. The tilde represents that any derivatives $D_\mu$ in $\Gamma$ appear as $\Dt_\mu$ in $\tilde{\Gamma}$. A typical contraction contributing to this correlation function is depicted in Fig. \[f:latcor\]. The kinematic effect due to twisting is uncovered by expressing the correlation function calculated on the lattice in terms of operators $\cN$ and $\cP$ built from the twisted quark fields $Q$. We have $$\begin{aligned}
C(t,t') &=& 
\langle \cPt (\bm{0}, t) \cOt_\mu(t') \ol \cNt (\bm{P},0) \rangle 
\notag \\
&=& 
