Excited neutron halo of ¹⁶N via the ¹⁶N^g,m(d,³He) reaction

We report on result from a study of the ¹⁶N^g,m(d,³He)¹⁵C reaction to explore the one neutron halo nucleus ¹⁵C. The radioactive ¹⁶N beam, with a 25% isomer component, was produced using the ATLAS RAISOR in-flight separator at ANL. The ¹⁶N^g,m(d,³He)¹⁵C proton removal reactions in inverse kinematics at 11.8 MeV/u was carried out using the HELIOS spectrometer. The simultaneous reactions provided the most direct and reliable comparison of the spectroscopic factors due to the cancellation of most of the systematic uncertainties from experiment and DWBA theory. The ratio of the spectroscopic factors between the ¹⁶N^g→¹⁵C(0.74) and ¹⁶N^m→¹⁵C(0.00) reactions was found to be 0.82±0.22. The result indicates that the s-orbital between ¹⁶N^m and ¹⁵C ground state is similar and the isomer state of ¹⁶N is an excited neutron halo state.