Parity-violating two-pion exchange nucleon-nucleon interaction

Understand

We calculate in chiral perturbation theory the parity-violating two-pion exchange nucleon-nucleon potentials at leading one-loop order.

• At a distance of $r= m_\pi^{-1} \simeq 1.4 $fm they amount to about $\pm 16%$ of the parity-violating $1\pi$-exchange potential.
• We evaluate also the parity-violating effects arising from $2\pi$-exchange with excitation of virtual $\Delta(1232)$-isobars.
• These come out to be relatively small in comparison to those from diagrams with only nucleon intermediate states.