Structure of [superscript 55]Ti from relativistic one-neutron knockout

Abstract

Results are presented from a one-neutron knockout reaction at relativistic energies on [superscript 56]Ti using the GSI FRS as a two-stage magnetic spectrometer and the MINIBALL array for gamma-ray detection. Inclusive and exclusive longitudinal momentum distributions and cross-sections were measured enabling the determination of the orbital angular momentum of the populated states. First-time observation of the 955(6) keV νp[superscript −1][subscript 3/2]-hole state in [superscript 55]Ti is reported. The measured data for the first time proves that the ground state of [superscript 55]Ti is a 1/2[superscript −] state, in agreement with shell-model calculations using the GXPF1A interaction that predict a sizable N = 34 gap in [superscript 54]Ca.