A precision mass investigation of the neutron-rich titanium isotopes ${}^{51-55}\mathrm{Ti}$ was performed at TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN). The range of the measurements covers the $N=32$ shell closure, and the overall uncertainties of the ${}^{52-55}\mathrm{Ti}$ mass values were significantly reduced. Our results conclusively establish the existence of the weak shell effect at $N=32$, narrowing down the abrupt onset of this shell closure. Our data were compared with state-of-the-art ab initio shell model calculations which, despite very successfully describing where the $N=32$ shell gap is strong, overpredict its strength and extent in titanium and heavier isotones. These measurements also represent the first scientific results of TITAN using the newly commissioned multiple-reflection time-of-flight mass spectrometer, substantiated by independent measurements from TITAN’s Penning trap mass spectrometer.

We report high-precision mass measurements of ${}^{50–55}\mathrm{Sc}$ isotopes performed at the LEBIT facility at NSCL and at the TITAN facility at TRIUMF. Our results provide a substantial reduction of their uncertainties and indicate significant deviations, up to 0.7 MeV, from the previously recommended mass values for ${}^{53–55}\mathrm{Sc}$. The results of this work provide an important update to the description of emerging closed-shell phenomena at neutron numbers $N=32$ and $N=34$ above proton-magic $Z=20$. In particular, they finally enable a complete and precise characterization of the trends in ground state binding energies along the $N=32$ isotone, confirming that the empirical neutron shell gap energies peak at the doubly magic ${}^{52}\mathrm{Ca}$. Moreover, our data, combined with other recent measurements, do not support the existence of a closed neutron shell in ${}^{55}\mathrm{Sc}$ at $N=34$. The results were compared to predictions from both ab initio and phenomenological nuclear theories, which all had success describing $N=32$ neutron shell gap energies but were highly disparate in the description of the $N=34$ isotone.

We present angular distributions of the He6+Ni58 scattering measured at three bombarding energies above the Coulomb barrier: Elab=12.2 MeV,16.5 MeV,and 21.7 MeV. The angular distributions have been analysed in terms of three- and four-body Continuum-Discretized Coupled-Channels calculations considering the effect of the 6He breakup. A behaviour in the cross section at large angles has been observed which was reproduced only by the four-body Continuum-Discretized Coupled-Channels calculation

We performed the first direct mass measurements of neutron-rich vanadium ${}^{52–55}\mathrm{V}$ isotopes passing the $N=32$ neutron shell closure with TRIUMF's Ion Trap for Atomic and Nuclear science. The new direct measurements confirm all previous indirect results. Through a reduced uncertainty of the mass of ${}^{55}\mathrm{V}$ we confirm the quenching of the $N=32$ neutron shell closure in vanadium. We discuss the evolution of the $N=32$ neutron shell closure between K and Cr and show similar signatures in the half-life surface when studied along the isotopic chains.