Charge Symmetry Violation in $pn\to d π^0$ as a Test of Chiral Effective Field Theory

Abstract

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 $pn\to dπ^0$, for reasonable values of the mass difference between down and up quarks, $δm_N$. Using a value $δm_N\approx$ 3 MeV leads to a prediction of a 10 standard deviation effect for a TRIUMF experiment.