Charge Symmetry Violation in $pn\to d \pi^0$ as a Test of Chiral   Effective Field Theory
  Chiral effective field theory predicts a specific charge symmetry violating amplitude for pion production. This term is shown to provide the dominant contribution to the forward-backward asymmetry in the angular distribution for the reaction $pn\to d\pi^0$, for reasonable values of the mass difference between down and up quarks, $\delta m_N$. Using a value $\delta m_N\approx$ 3 MeV leads to a prediction of a 10 standard deviation effect for a TRIUMF experiment. 
U. van Kolck, J.A. Niskanen, and G.A. Miller