Dawning of the $N=32$ Shell Closure Seen through Precision Mass Measurements of Neutron-Rich Titanium Isotopes

E. Leistenschneider , M.P. Reiter , S. Ayet San Andrés , B. Kootte , J.D. Holt , P. Navrátil , C. Babcock , C. Barbieri , B.R. Barquest , J. Bergmann , J. Bollig , T. Brunner , E. Dunling , A. Finlay , H. Geissel , L. Graham , F. Greiner , H. Hergert , C. Hornung , C. Jesch , R. Klawitter , Y. Lan , D. Lascar , K.G. Leach , W. Lippert , J.E. Mckay , S.F. Paul , A. Schwenk , D. Short , J. Simonis , V. Somà (1) , R. Steinbrügge , S.R. Stroberg , R. Thompson , M.E. Wieser , C. Will , M. Yavor , C. Andreoiu , T. Dickel , I. Dillmann , G. Gwinner , W.R. Plaß , C. Scheidenberger , A.A. Kwiatkowski , J. Dilling

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers

A precision mass investigation of the neutron-rich titanium isotopes Ti51-55 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 Ti52-55 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.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

E. Leistenschneider, M.P. Reiter, S. Ayet San Andrés, B. Kootte, J.D. Holt, et al.. Dawning of the $N=32$ Shell Closure Seen through Precision Mass Measurements of Neutron-Rich Titanium Isotopes. Physical Review Letters, 2018, 120 (6), pp.062503. ⟨10.1103/PhysRevLett.120.062503⟩. ⟨hal-01714789⟩