Parity Violating Photoproduction of $π^\pm$ on the $Δ$ Resonance

Abstract

We analyze the real photon asymmetry $A^\pm_γ$ for the parity violating (PV) $π^\pm$ production on the $Δ$ resonance via the reactions ${\vec γ} + p \to Δ^+ \to π^+ + n$ and ${\vec γ} + d \to Δ^0 + p \to π^- + p + p$. This asymmetry is nonvanishing due to a PV $γN Δ$ coupling constant, $d^\pm_Δ$. We argue that an experimental determination of this coupling would be of interest for hadron dynamics, possibly shedding light on the S-wave/P-wave puzzle in the hyperon nonleptonic decays and the violation of Hara's theorem in weak radiative hyperon decays.