Parity violating asymmetry in $\vec{\gamma} + d \rightarrow n + p$ at low energy

Abstract

We calculate the parity-violating asymmetry in the $\vec{\gamma} + d \rightarrow n + p$ process where the deuteron is disintegrated by circular photons. The photon energy is considered up to 10 MeV above threshold, where the lowest electromagnetic transition modes M1 and E1 dominate. We employ the Argonne v18 potential for the strong interaction and the DDH potential for the parity-violating weak interaction of the two-nucleon systems. The asymmetry is about 2.5 × 10^–8 at threshold, and decreases rapidly to have magnitude of order 10^–9 or less for photon energies larger than 3 MeV. The exchange of vector mesons dominates the asymmetry, while the pion contribution is negligible.

PACS: 24.80.+y Nuclear tests of fundamental interactions and symmetries