Can spatial distributions of deeply bound nucleons in unstable nuclei be determined by a (p,pN) reaction?

 Unique phenomena such as neutron halos, which are not found in stable nuclei, have been discovered in nuclei far from stability, especially neutron excess. Weakly bound states, which are the cause of these phenomena, have been studied in various ways, but deeply bound states remain unexplored. Therefore, in order to obtain systematic information on proton single-particle orbitals of carbon isotopes, especially deeply bound 1s_1/2 orbitals, experiments of ^9-16C(p,2p) knockout reactions were performed at HIMAC, National Institute of Radiological Sciences. In the previous study, the 1s_1/2 orbitals were selected by identifying residual nuclei. The radius of the 1s_1/2 orbit was then obtained by Fourier transform of the momentum distribution.

 In this study, we discuss methods for extracting the size of the 1s_1/2 orbital from the measured momentum distribution. For example, in case of stable nuclei, the multipole decomposition is used to discriminate orbits. We verify whether the technique can be applied to the momentum distribution, and discuss the difference between the obtained radius and the values in the previous study. In this presentation, the results will be discussed.