Open AccessRotational band structure inMg 32
Author(s) -
H. L. Crawford,
P. Fallon,
A. O. Macchiavelli,
A. Poves,
V. M. Bader,
D. Bazin,
M. Bowry,
C. M. Campbell,
M. P. Carpenter,
R. M. Clark,
M. Cromaz,
A. Gade,
E. Ideguchi,
H. Iwasaki,
C. Langer,
I. Y. Lee,
C. Loelius,
E. Lunderberg,
C. Morse,
A. Richard,
J. Rissanen,
D. Smalley,
S. R. Stroberg,
D. Weißhaar,
K. Whitmore,
A. Wiens,
S. J. Williams,
K. Wimmer,
T. Yamamato
Publication year - 2016
Publication title -
physical review. c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.679
H-Index - 235
eISSN - 2469-9993
pISSN - 2469-9985
DOI - 10.1103/physrevc.93.031303
Subject(s) - physics , atomic physics , yrast , angular momentum , pairing , excited state , condensed matter physics , quantum mechanics , superconductivity
There is significant evidence supporting the existence of deformed ground states within the neutron-rich N≈20 neon, sodium, and magnesium isotopes that make up what is commonly called the "island of inversion." However, the rotational band structures, which are a characteristic fingerprint of a rigid nonspherical shape, have yet to be observed. In this work, we report on a measurement and analysis of the yrast (lowest lying) rotational band in Mg32 up to spin I=6+ produced in a two-step projectile fragmentation reaction and observed using the state-of-the-art γ-ray tracking detector array, GRETINA (γ-ray energy tracking in-beam nuclear array). Large-scale shell-model calculations using the SDPF-U-MIX effective interaction show excellent agreement with the new data. Moreover, a theoretical analysis of the spectrum of rotational states as a function of the pairing gap, together with cranked-shell-model calculations, provides intriguing evidence for a reduction in pairing correlations with increased angular momentum, also in line with the shell-model resultsThis material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contracts No. DE-AC02-05CH11231 (LBNL) and No. DE-AC02-06CH11357 (ANL), by the Department of Energy National Nuclear Security Administration under Award No. DE-NA0000979 and the National Science Foundation (NSF) under PHY-1102511. GRETINA was funded by the U.S. DOE Office of Science. Operation of the array at NSCL is supported by NSF under Cooperative Agreement PHY11-02511 (NSCL) and DOE under Grant No. DE-AC02- 05CH11231 (LBNL). A.P. is partly supported by MINECO (Spain) Grant FPA2014-57196 and Programme “Centros de Excelencia Severo Ochoa” SEV-2012-024