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Clarifying the 𝑁,𝑍 = 14 Shells near the Drip Lines from the Spectroscopy of 22Si and 21Al

Journal Article · · Physical Review Letters
DOI:https://doi.org/10.1103/v57q-45qj· OSTI ID:3008486
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  1. Washington University, St. Louis, MO (United States)
  2. Washington University, St. Louis, MO (United States); Facility for Rare Isotope Beams, East Lansing, MI (United States)
  3. Michigan State University, East Lansing, MI (United States)
  4. Michigan State University, East Lansing, MI (United States); University of Warsaw (Poland)
+ Show Author Affiliations
Evidence for a (sub)-shell closure at 𝑍 = 14 has been observed from the spectroscopy of 22Si and 21Al . Using a fast 23Si beam on a 9Be target, several proton-decaying resonances have been populated in 21Al and 22Si , including the first measurement of the 2$$^{+}_{1}$$ state in 22Si with an excitation energy of 2.352(55) MeV. Relative to the known 𝑁 = 14 subshell closure in 22O , the 22Si 2$$^{+}_{1}$$ excitation energy indicates the existence of a weakened 𝑍 = 14 subshell closure. To reproduce the new spectroscopic information and known 22Al levels, the energy of the 1⁒𝑠1/2 orbit must be substantially decreased, which imparts Thomas-Ehrman shifts to all excited states observed in the present Letter and explains the structure of nuclei in the 𝑠⁒𝑑 shell for this region of the proton drip line.
Research Organization:
Washington University in St. Louis, MO (United States)
Sponsoring Organization:
National Science Foundation (NSF); National Science Foundation Graduate Research Fellowship (GRF); USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); USDOE Office of Science (SC), Nuclear Physics (NP)
Grant/Contract Number:
FG02-87ER40316; NA0004150; SC0021938; SC0022299; SC0023633
OSTI ID:
3008486
Journal Information:
Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 25 Vol. 135; ISSN 1079-7114; ISSN 0031-9007
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English

References (31)

Multiple angular scattering of heavy ions (16,17O, 40Ar, 86Kr and 100Mo) at intermediate energies (20–90 MeV/u) journal September 1988
The S800 spectrograph journal May 2003
Focal plane detector for the S800 high-resolution spectrometer
  • Yurkon, J.; Bazin, D.; Benenson, W.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 422, Issue 1-3 https://doi.org/10.1016/S0168-9002(98)00960-7
journal February 1999
Spectroscopy of the 21+ state in 22O and shell structure near the neutron drip line journal July 2000
The high resolution array (HiRA) for rare isotope beam experiments
  • Wallace, M. S.; Famiano, M. A.; van Goethem, M. -J.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 583, Issue 2-3 https://doi.org/10.1016/j.nima.2007.08.248
journal December 2007
CAESARβ€”A high-efficiency CsI(Na) scintillator array for in-beam spectroscopy with fast rare-isotope beams
  • Weisshaar, D.; Gade, A.; Glasmacher, T.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 624, Issue 3 https://doi.org/10.1016/j.nima.2010.09.148
journal December 2010
SRIM – The stopping and range of ions in matter (2010)
  • Ziegler, James F.; Ziegler, M. D.; Biersack, J. P.
  • Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 268, Issue 11-12 https://doi.org/10.1016/j.nimb.2010.02.091
journal June 2010
Observation of three-proton-decaying resonant states in 21Al journal September 2025
Facility for Rare Isotope Beams Update for Nuclear Physics News journal April 2017
Shell model in the complex energy plane journal October 2008
The AME 2020 atomic mass evaluation (II). Tables, graphs and references* journal March 2021
Development of a novel MPGD-based drift chamber for the NSCL/FRIB S800 spectrometer journal March 2020
On the Displacement of Corresponding Energy Levels of C 13 and N 13 journal February 1951
An Analysis of the Energy Levels of the Mirror Nuclei, C 13 and N 13 journal December 1952
Description of proton-rich nuclei in the A β‰ˆ 20 region within the Gamow shell model journal December 2019
New isospin-breaking β€œUSD” Hamiltonians for the sd shell journal June 2020
Observation and spectroscopy of the proton-unbound nucleus Al21 journal September 2024
Neutron magicity in the proton drip-line nucleus Mg20 : First invariant-mass reconstruction of Mg19,20 journal December 2024
N = 14 and 16 shell gaps in neutron-rich oxygen isotopes journal March 2004
Continuum shell model journal December 2006
Spectroscopy of Mg 20 : The isobaric mass multiplet equation for the 2 + states of the A = 20 , T = 2 quintet and distant mirror nuclei journal August 2007
Electromagnetic transitions in neutron-rich F 22 journal September 2007
Observation of excited states in Mg 20 sheds light on nuclear forces and shell evolution journal February 2019
Invariant-mass spectroscopy of Ne 18 ,   O 16 , and C 10 excited states formed in neutron-transfer reactions journal April 2019
Hindered Proton Collectivity in S 12 16 28 : Possible Magic Number at Z = 16 journal May 2012
N = 16 Spherical Shell Closure in O 24 journal July 2012
Large Isospin Asymmetry in Si 22 / O 22 Mirror Gamow-Teller Transitions Reveals the Halo Structure of Al 22 journal November 2020
Precision Mass Measurement of the Proton Dripline Halo Candidate Al22 journal April 2024
Gamow Shell Model Description of Neutron-Rich Nuclei journal July 2002
Evolution of shell structure in exotic nuclei journal March 2020
Z=14 Magicity Revealed by the Mass of the Proton Dripline Nucleus Si22 journal July 2025

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