Circular polarization of γ-quanta in the n + p → d + γ reaction and the weak P-violating NN ϱ vertex

Abstract

Theoretical estimates for the circular polarization of γ-quanta in the n + p → d + γ reaction usually yield a value about two orders of magnitude below the value given by the experimental data. These estimates use the conventional value for the constant Γ( m ϱ 2) of the weak P-violating interaction of nucleons with ϱ-mesons, based on the consideration of the simplest graph. The present work shows that the graphs for Γ( m ϱ 2) which ordinarily are not taken into account are in reality quadratically divergent and hence, large (the weak Hamiltonian density being assumed here to have the current-current form). If the cut-off parameter in the quadratically divergent integral determining the quantity Γ( m ϱ 2) is chosen to be Λ ∼ 10 GeV, then the discrepancy between the theory and experiment disappears.