First Observation of the Four-Proton Unbound Nucleus 18Mg

Jin, Y.; Niu, C. Y.; Brown, K. W.; Li, Z. H.; Hua, H.; Anthony, A. K.; Barney, J.; Charity, R. J.; Crosby, J.; Dell’Aquila, D.; Elson, J. M.; Estee, J.; Ghazali, M.; Jhang, G.; Li, J. G.; Lynch, W. G.; Michel, N.; Sobotka, L. G.; Sweany, S.; Teh, F. C. E.; Thomas, A.; Tsang, C. Y.; Tsang, M. B.; Wang, S. M.; Wu, H. Y.; Yuan, C.  X.; Zhu, K.

doi:10.1103/physrevlett.127.262502

Title: First Observation of the Four-Proton Unbound Nucleus ¹⁸Mg

Journal Article · Wed Dec 22 00:00:00 EST 2021 · Physical Review Letters

DOI:https://doi.org/10.1103/physrevlett.127.262502· OSTI ID:1837749

^[1]; Niu, C. Y. ^[2]; Brown, K. W. ^[2]; Li, Z. H. ^[1]; Hua, H. ^[1]; Anthony, A. K. ^[2]; Barney, J. ^[2]; Charity, R. J. ^[3]; Crosby, J. ^[2]; Dell’Aquila, D. ^[2]; Elson, J. M. ^[3]; Estee, J. ^[2]; Ghazali, M. ^[2]; Jhang, G. ^[2]; Li, J. G. ^[4]; Lynch, W. G. ^[2]; Michel, N. ^[5]; Sobotka, L. G. ^[3]; Sweany, S. ^[2]; Teh, F. C. E. ^[2] more »

Peking Univ., Beijing (China)
Michigan State Univ., East Lansing, MI (United States)
Washington Univ., St. Louis, MO (United States)
Peking Univ., Beijing (China); Chinese Academy of Sciences, Lanzhou (China); Univ. of Chinese Academy of Sciences, Beijing (China)
Chinese Academy of Sciences, Lanzhou (China); Univ. of Chinese Academy of Sciences, Beijing (China)
Fudan Univ., Shanghai (China); Michigan State Univ., East Lansing, MI (United States)
Sun Yat-Sen Univ., Zhuhai (China)

¹⁸Mg was observed, for the first time, by the invariant-mass reconstruction of ¹⁴O + 4p events. The ground-state decay energy and width are E_T = 4.865(34) MeV and Γ = 115(100) keV, respectively. The observed momentum correlations between the five particles are consistent with two sequential steps of prompt 2p decay passing through the ground state of ¹⁶Ne. The invariant-mass spectrum also provides evidence for an excited state at an excitation energy of 1.84(14) MeV, which is likely the first excited 2⁺ state. As this energy exceeds that for the 2⁺ state in ²⁰Mg, this observation provides an argument for the demise of the N = 8 shell closure in nuclei far from stability. Furthermore, in open systems this classical argument for shell strength is compromised by Thomas-Ehrman shifts.

View Accepted Manuscript (DOE)

Cite

Export

Save

Research Organization:: Washington Univ., St. Louis, MO (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Nuclear Physics (NP)

Grant/Contract Number:: FG02-87ER40316

OSTI ID:: 1837749

Journal Information:: Physical Review Letters, Vol. 127, Issue 26; ISSN 0031-9007

Publisher:: American Physical Society (APS)Copyright Statement

Country of Publication:: United States

Language:: English

References (35)

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
Shell model in the complex energy plane Michel, N.; Nazarewicz, W.; Płoszajczak, M. Journal of Physics G: Nuclear and Particle Physics, Vol. 36, Issue 1 https://doi.org/10.1088/0954-3899/36/1/013101	journal	October 2008
Radioactive decays at limits of nuclear stability Pfützner, M.; Karny, M.; Grigorenko, L. V. Reviews of Modern Physics, Vol. 84, Issue 2 https://doi.org/10.1103/RevModPhys.84.567	journal	April 2012
Observation of Long-Range Three-Body Coulomb Effects in the Decay of ${}^{16}{Ne}$ Brown, K. W.; Charity, R. J.; Sobotka, L. G. Physical Review Letters, Vol. 113, Issue 23 https://doi.org/10.1103/PhysRevLett.113.232501	journal	December 2014
Improved Kelson-Garvey mass relations for proton-rich nuclei Tian, Junlong; Wang, Ning; Li, Cheng Physical Review C, Vol. 87, Issue 1 https://doi.org/10.1103/PhysRevC.87.014313	journal	January 2013
Commissioning the A1900 projectile fragment separator Morrissey, D. J.; Sherrill, B. M.; Steiner, M. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 204 https://doi.org/10.1016/S0168-583X(02)01895-5	journal	May 2003
$N = 14$ Shell Closure in ${}^{22}O$ Viewed through a Neutron Sensitive Probe Becheva, E.; Blumenfeld, Y.; Khan, E. Physical Review Letters, Vol. 96, Issue 1 https://doi.org/10.1103/PhysRevLett.96.012501	journal	January 2006
First Observation of ${}^{54}{Zn}$ and its Decay by Two-Proton Emission Blank, B.; Bey, A.; Canchel, G. Physical Review Letters, Vol. 94, Issue 23 https://doi.org/10.1103/PhysRevLett.94.232501	journal	June 2005
Observation of the Exotic Isotope ${}^{13}F$ Located Four Neutrons beyond the Proton Drip Line Charity, R. J.; Webb, T. B.; Elson, J. M. Physical Review Letters, Vol. 126, Issue 13 https://doi.org/10.1103/PhysRevLett.126.132501	journal	March 2021
Proton-decaying states in light nuclei and the first observation of ${}^{17}{Na}$ Brown, K. W.; Charity, R. J.; Elson, J. M. Physical Review C, Vol. 95, Issue 4 https://doi.org/10.1103/PhysRevC.95.044326	journal	April 2017
Masses of ${}^{17, 18, 19, 20}{Mg}$ Fortune, H. T. Physical Review C, Vol. 94, Issue 4 https://doi.org/10.1103/PhysRevC.94.044305	journal	October 2016
Observation of excited states in ${}^{20}{Mg}$ sheds light on nuclear forces and shell evolution Randhawa, J. S.; Kanungo, R.; Holl, M. Physical Review C, Vol. 99, Issue 2 https://doi.org/10.1103/PhysRevC.99.021301	journal	February 2019
Spectroscopy of the 21+ state in 22O and shell structure near the neutron drip line Thirolf, P. G.; Pritychenko, B. V.; Brown, B. A. Physics Letters B, Vol. 485, Issue 1-3 https://doi.org/10.1016/S0370-2693(00)00720-6	journal	July 2000
The S800 spectrograph Bazin, D.; Caggiano, J. A.; Sherrill, B. M. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 204 https://doi.org/10.1016/S0168-583X(02)02142-0	journal	May 2003
Observation of Two-Proton Radioactivity of ${}^{19}{Mg}$ by Tracking the Decay Products Mukha, I.; Sümmerer, K.; Acosta, L. Physical Review Letters, Vol. 99, Issue 18 https://doi.org/10.1103/PhysRevLett.99.182501	journal	October 2007
Shell structure of exotic nuclei Dobaczewski, J.; Michel, N.; Nazarewicz, W. Progress in Particle and Nuclear Physics, Vol. 59, Issue 1 https://doi.org/10.1016/j.ppnp.2007.01.022	journal	July 2007
Production of rare isotope beams with the NSCL fragment separator Stolz, A.; Baumann, T.; Ginter, T. N. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Vol. 241, Issue 1-4 https://doi.org/10.1016/j.nimb.2005.07.168	journal	December 2005
Investigations of three-, four-, and five-particle decay channels of levels in light nuclei created using a ${}^{9}C$ beam Charity, R. J.; Elson, J. M.; Manfredi, J. Physical Review C, Vol. 84, Issue 1 https://doi.org/10.1103/PhysRevC.84.014320	journal	July 2011
Democratic Decay of ${}^{6}{Be}$ Exposed by Correlations Egorova, I. A.; Charity, R. J.; Grigorenko, L. V. Physical Review Letters, Vol. 109, Issue 20 https://doi.org/10.1103/PhysRevLett.109.202502	journal	November 2012
On neutron-deficient isotopes of light nuclei and the phenomena of proton and two-proton radioactivity Goldansky, V. I. Nuclear Physics, Vol. 19 https://doi.org/10.1016/0029-5582(60)90258-3	journal	September 1960
First Observation of Unbound ${}^{11}O$ , the Mirror of the Halo Nucleus ${}^{11}{Li}$ Webb, T. B.; Wang, S. M.; Brown, K. W. Physical Review Letters, Vol. 122, Issue 12 https://doi.org/10.1103/PhysRevLett.122.122501	journal	March 2019
${}^{19}{Mg}$ two-proton decay lifetime Voss, P.; Baumann, T.; Bazin, D. Physical Review C, Vol. 90, Issue 1 https://doi.org/10.1103/PhysRevC.90.014301	journal	July 2014
First Observation of the Unbound Nucleus ${}^{15}{Ne}$ Wamers, F.; Marganiec, J.; Aksouh, F. Physical Review Letters, Vol. 112, Issue 13 https://doi.org/10.1103/PhysRevLett.112.132502	journal	April 2014
Two-Proton Correlations in the Decay of ${}^{45}{Fe}$ Miernik, K.; Dominik, W.; Janas, Z. Physical Review Letters, Vol. 99, Issue 19 https://doi.org/10.1103/PhysRevLett.99.192501	journal	November 2007
Two-Proton Emission from the Ground State of ${}^{12}O$ Kryger, R. A.; Azhari, A.; Hellström, M. Physical Review Letters, Vol. 74, Issue 6 https://doi.org/10.1103/PhysRevLett.74.860	journal	February 1995
The shell model as a unified view of nuclear structure Caurier, E.; Martínez-Pinedo, G.; Nowacki, F. Reviews of Modern Physics, Vol. 77, Issue 2 https://doi.org/10.1103/RevModPhys.77.427	journal	June 2005
Proton decays in ${}^{16}{Ne}$ and ${}^{18}{Mg}$ and isospin-symmetry breaking in carbon isotopes and isotones Michel, N.; Li, J. G.; Xu, F. R. Physical Review C, Vol. 103, Issue 4 https://doi.org/10.1103/PhysRevC.103.044319	journal	April 2021
Mass of $^{18}$ Mg(g.s.) Fortune, H. T.; Sherr, R. Physical Review C, Vol. 87, Issue 4 https://doi.org/10.1103/PhysRevC.87.044315	journal	April 2013
Particle decays of levels in ${}^{11, 12}N$ and ${}^{12}O$ investigated with the invariant-mass method Webb, T. B.; Charity, R. J.; Elson, J. M. Physical Review C, Vol. 100, Issue 2 https://doi.org/10.1103/PhysRevC.100.024306	journal	August 2019
An Analysis of the Energy Levels of the Mirror Nuclei, $C^{13}$ and $N^{13}$ Thomas, R. G. Physical Review, Vol. 88, Issue 5 https://doi.org/10.1103/PhysRev.88.1109	journal	December 1952
On the Displacement of Corresponding Energy Levels of $C^{13}$ and $N^{13}$ Ehrman, Joachim B. Physical Review, Vol. 81, Issue 3 https://doi.org/10.1103/PhysRev.81.412	journal	February 1951
$2 p$ - $2 p$ decay of $^{8} C$ and isospin-allowed $2 p$ decay of the isobaric-analog state in $^{8} B$ Charity, R. J.; Elson, J. M.; Manfredi, J. Physical Review C, Vol. 82, Issue 4 https://doi.org/10.1103/PhysRevC.82.041304	journal	October 2010
A multi-channel integrated circuit for use in low- and intermediate-energy nuclear physics—HINP16C Engel, George L.; Sadasivam, Muthukumar; Nethi, Mythreyi Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 573, Issue 3 https://doi.org/10.1016/j.nima.2006.12.052	journal	April 2007
The AME 2020 atomic mass evaluation (II). Tables, graphs and references* Wang, Meng; Huang, W. J.; Kondev, F. G. Chinese Physics C, Vol. 45, Issue 3 https://doi.org/10.1088/1674-1137/abddaf	journal	March 2021
Two-Proton Radioactivity of ${}^{67}{Kr}$ Goigoux, T.; Ascher, P.; Blank, B. Physical Review Letters, Vol. 117, Issue 16 https://doi.org/10.1103/PhysRevLett.117.162501	journal	October 2016

Similar Records

Neutron-unbound states in ³¹Ne

Journal Article · Wed Sep 15 00:00:00 EDT 2021 · Physical Review C · OSTI ID:1837749

Chrisman, D.; Kuchera, A. N.; Baumann, T.; +21 more

Spectroscopy of neutron-unbound high spin states in /sup 25/Mg

Thesis/Dissertation · Thu Jan 01 00:00:00 EST 1987 · OSTI ID:1837749

Headly, D M

Structure of /sup 14/C via elastic and inelastic neutron scattering from /sup 13/C: Measurement, R-matrix analysis, and shell model calculations

Technical Report · Sun Mar 01 00:00:00 EST 1987 · OSTI ID:1837749

Resler, D A

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Lifetimes & widths
Nuclear structure & decays
Proton emission
Rare & new isotopes
6 ≤ A ≤ 19
Radioactive beams

Title: First Observation of the Four-Proton Unbound Nucleus 18Mg

Citation Formats

References (35)

Similar Records

Related Subjects

Title: First Observation of the Four-Proton Unbound Nucleus ¹⁸Mg