Are There Signatures of Harmonic Oscillator Shells Far from Stability? First Spectroscopy of ^{110}Zr.

Physical review letters

PubMedID: 28157341

Paul N, Corsi A, Obertelli A, Doornenbal P, Authelet G, Baba H, Bally B, Bender M, Calvet D, Château F, Chen S, Delaroche JP, Delbart A, Gheller JM, Giganon A, Gillibert A, Girod M, Heenen PH, Lapoux V, Libert J, Motobayashi T, Niikura M, Otsuka T, Rodríguez TR, Roussé JY, Sakurai H, Santamaria C, Shimizu N, Steppenbeck D, Taniuchi R, Togashi T, Tsunoda Y, Uesaka T, Ando T, Arici T, Blazhev A, Browne F, Bruce AM, Carroll R, Chung LX, Cortés ML, Dewald M, Ding B, Flavigny F, Franchoo S, Górska M, Gottardo A, Jungclaus A, Lee J, Lettmann M, Linh BD, Liu J, Liu Z, Lizarazo C, Momiyama S, Moschner K, Nagamine S, Nakatsuka N, Nita C, Nobs CR, Olivier L, Patel Z, Podolyák Z, Rudigier M, Saito T, Shand C, Söderström PA, Stefan I, Orlandi R, Vaquero V, Werner V, Wimmer K, Xu Z. Are There Signatures of Harmonic Oscillator Shells Far from Stability? First Spectroscopy of ^{110}Zr. Phys Rev Lett. 2017;118(3):032501.
The first measurement of the low-lying states of the neutron-rich ^{110}Zr and ^{112}Mo was performed via in-beam ?-ray spectroscopy after one proton removal on hydrogen at ~200??MeV/nucleon. The 2_{1}^{+} excitation energies were found at 185(11) keV in ^{110}Zr, and 235(7) keV in ^{112}Mo, while the R_{42}=E(4_{1}^{+})/E(2_{1}^{+}) ratios are 3. 1(2), close to the rigid rotor value, and 2. 7(1), respectively. These results are compared to modern energy density functional based configuration mixing models using Gogny and Skyrme effective interactions. We conclude that first levels of ^{110}Zr exhibit a rotational behavior, in agreement with previous observations of lighter zirconium isotopes as well as with the most advanced Monte Carlo shell model predictions. The data, therefore, do not support a harmonic oscillator shell stabilization scenario at Z=40 and N=70. The present data also invalidate predictions for a tetrahedral ground state symmetry in ^{110}Zr.