The electric dipole form factor of the nucleon stemming from the QCD θ term is calculated in chiral perturbation theory in leading order. To this order, the form factor originates from the pion cloud. Its momentum-dependence is proportional to a non-derivative time-reversal-violating pion-nucleon coupling, and the scale for momentum variation - appearing, in particular, in the radius of the form factor - is the pion mass.
ASJC Scopus subject areas
- Nuclear and High Energy Physics