  The electroweak interaction at the level of quarks and gluons are well
understood from precision measurements in high energy collider experiments.
Relating these fundamental parameters to Hadronic Parity Violation in nuclei
however remains an outstanding theoretical challenge. One of the most
interesting observables in this respect is the parity violating hadronic
neutral current: it is hard to measure in collider experiments and is thus the
least constrained observable of the Standard Model. Precision measurements of
parity violating transitions in nuclei can help to improve these constraints.
In these systems however, the weak interaction is masked by effects of the
seven orders of magnitude stronger non-perturbative strong interaction.
Therefore, in order to relate experimental measurements of the parity violating
pion-nucleon couplings to the fundamental Lagrangian of the SM, these
non-perturbative effects have to be well understood. In this paper, we are
going to present a Lattice QCD approach for computing the $\Delta I{=}2$ parity
violating matrix element in proton proton scattering. This process does not
involve disconnected diagrams in the isospin symmetric limit and is thus a
perfect testbed for studying the feasibility of the more involved calculation
of the parity violating pion-nucleon coupling.
