Studies on electromagnetic dipole responses of atomic nuclei at RCNP

Electric dipole (E1) and spin-magnetic dipole (spin-M1) responses of nuclei have been studied by proton inelastic scattering experiments at forward angles, including zero degrees, at the Research Center for Nuclear Physics (RCNP) by employing a proton beam 295 or 392 MeV and the high-resolution magnetic spectrometer Grand Raiden. The E1 response of nuclei is the most fundamental nuclear response to the external field and is relevant to photo-nuclear reactions. After introducing the relevant nuclear matrix elements and the experimental methods, several recent experimental works are highlighted that include (E1) polarizability and the extraction of the symmetry energy parameters, pygmy dipole resonance, gamma-coincidence measurements, isoscalar and isovector spin-M1 excitations and the np spin correlation in the ground state, and gamma-emission probability for neutral current neutrino detection. A project, PANDORA, is introduced that aims at a systematic study of photo-nuclear reactions and decay branching ratios for light nuclei.