Coulomb breakup of 23O

The ground-state structure of the near-drip-line nucleus 23O has been investigated in a one-neutron Coulomb breakup reaction. Differential cross sections dσ/dE* for electromagnetic excitation of 23O projectiles (422 MeV/nucleon) incident on a lead target have been obtained from the measurement of the momenta of all breakup products including γ rays. The analysis of the deduced dipole-transition probability into the continuum infers a 2s1/2⊗O22(0+) ground state configuration with a spectroscopic factor of 0.77(10) and thus a ground-state spin Iπ(O23)=1/2+, resolving earlier conflicting experimental findings. Final-state interaction is of significant influence, an effective reduced scattering length for low-energy p3/2 neutron scattering could be derived from the data.