Proton Inelastic Scattering on ${}_{}{}^{56}{}_{}{}^{}\mathrm{Ni}$ in Inverse Kinematics

Inelastic proton scattering to the first excited $2^{+}$ state of the doubly magic ${}_{}{}^{56}{}_{}{}^{}\mathrm{Ni}$ nucleus was investigated in inverse kinematics, using a secondary beam of radioactive ${}_{}{}^{56}{}_{}{}^{}\mathrm{Ni}$ nuclei. At an incident energy of 101 MeV/nucleon, a value $B(E2,0^{+}\to 2^{+})=600\mathrm{}\pm 120 e^2$ ${\mathrm{fm}}^4$ was measured. This result completes the set of experimental data for the first excited $2^{+}$ states in the $1f-2p$ shell with a closed shell of neutrons or protons. These data are compared to recent shell-model calculations.