the two pairs are separated by a distance that varies up to the nuclear size. In this manner, aside from an overall factor of $A$ which reflects growth with the nuclear volume, we anticipate an $A^{1/3}$ nuclear enhancement [@LQS2].

Direct measurement of the multiparton correlation functions is of great importance for testing the generalized QCD factorization theorem [@QS_fac], which allows us to apply QCD perturbation theory for studying the collisions involving nuclei. It was observed in Ref. [@Guo2] that measuring the jet transverse momentum broadening in DIS, $\Delta\langle p_T^2\rangle$, provides a [*direct*]{} measurement of the quark-gluon correlation functions, $T^A_{qF}(x_B,Q^2)$, inside a nucleus. At the lowest order, the jet transverse momentum broadening in DIS can be expressed as [@Guo2] $$\begin{aligned}
\Delta\langle p_T^2\rangle &\equiv & 
\langle p_T^2\rangle^{eA} - \langle p_T^2\rangle^{eN} 
\nonumber \\
&\approx & \frac{4\pi^2\alpha_s(Q^2)}{3}\,
    \frac{\sum_q e_q^2\,T_{qF}^{A}(x_B,Q^2)}
         {\sum_q e_q^2\,q^{A}(x_B,Q^2)}\, ,
\label{jetdis}\end{aligned}$$ where $p_T$ is the transverse component of the jet momentum in the photon-nucleus center of mass frame in DIS. In Eq. (\[jetdis\]), $x_B$ is the Bjorken variable and $Q^2=-q^2$ with $q^2$ is the invariant mass of the virtual photon in DIS.

However, other than a future HERA with a nuclear beam, existing fixed target facilities can not provide good measurements on 