Polarized photon scattering of $^{52}$Cr: Determining the parity of dipole states

Observation of dipole states in nuclei are important because they provide information on various collective and single-particle nuclear excitation modes, e.g., pygmy dipole resonance (PDR) and spin-flip M1 resonance. The PDR has been extensively studied in the higher and medium mass region, whereas not much information is available around the low mass (A $\sim$ 50) region where, apparently,the PDR starts to form. The present photoresponse of $^{52}$Cr has been investigated to test the evolution of the PDR in a nucleus with a small number of excess neutrons as well as to look for spin-flip M1 resonance excitation mode. Spin-1 states in $^{52}$Cr between 5.0 to 9.5 MeV excitation energy were excited by exploiting fully polarized photons using the $(\gamma,\gamma^{'})$ nuclear resonance fluorescence technique, a completely model-independent electromagnetic method. The de-excitation $\gamma$-rays were detected using a HPGe array. The experiment was carried out using the HIGS facility at TUNL. Results of unambiguous parity determinations of dipole states in $^{52}$Cr will be presented.