The evidence of $N=16$ shell closure and $β$-delayed neutron emission from $^{25}$F

We measured the $β$-delayed neutron emission from $^{25}$F for the first time at the Facility for Rare Isotope Beams (FRIB). Using combined neutron and $γ$-ray detector systems of the FRIB Decay Station Initiator (FDSi), we observed $β$-decay transitions populating neutron unbound states between 4.2 and 8 MeV in $^{25}$Ne. The experimental results led to the revision of the $β$-decay half-life and $β$-delayed neutron-emission probability of $^{25}$F. The $β$-decay strength distribution of $^{25}$F extracted from the data agrees with the shell-model predictions using the USDB and SDPF-M effective interactions. This result indicates that the spherical neutron $N = 16$ shell gap persists in $^{25}$F and $^{25}$Ne.