Low-lying single-particle structure of 17C and the N = 14 sub-shell closure

The first investigation of the single-particle structure of the bound states of 17C, via the d(16C, p) transfer reaction, has been undertaken. The measured angular distributions confirm the spin-parity assignments of 1/2+ and 5/2+ for the excited states located at 217 and 335 keV, respectively. The spectroscopic factors deduced for these states exhibit a marked single-particle character, in agreement with shell model and particle-core model calculations, and combined with their near degeneracy in energy provide clear evidence for the absence of the N = 14 sub-shell closure. The very small spectroscopic factor found for the 3/2+ ground state is consistent with theoretical predictions and indicates that the ν1d3/2 strength is carried by unbound states. With a dominant = 0 valence neutron configuration and a very low separation energy, the 1/2+ excited state is a one-neutron halo candidate.Consejo de Instalaciones Científicas y Tecnológicas de UKRI. Reino Unido P003885Agencia Estatal de Investigación de España. Programa Ramón y Cajal RYC-2010-06484 y RYC-2012-11585Ministerio de Economia, Industria y Competitividad (MINECO) de España No. FPA2013-46236-PMinisterio de Ciencia, Innovación y Universidades español y los fondos FEDER FIS2017-88410-P y RTI2018-098117-B-C21El programa de investigación e innovación Horizon 2020 de la Unión Europea Subvención No. 65400

Spectroscopy of ¹⁷C via one-neutron knockout reaction

21st International Conference on Few-Body Problems in Physics, Chicago, IL, USA, May 18-22, 2015.A spectroscopic study of ¹⁷C was performed via the one-neutron knockout reaction of ¹⁸C on a carbon target at RIKEN-RIBF. Three unbound states at excitation energies of 2.66(2), 3.16(5), and 3.97(3) MeV (preliminary) were observed. The energies are compared with shell-model calculations and existing measurements to deduce their spin-parities. From the comparison, the states at 2.66(2) and 3.97(3) MeV are suggested to be 1/2⁻ and 3/2⁻, respectively. From its decay property, the state at 3.16(5) MeV is indicated to be 9/2⁺

Study of ¹⁹C by One-Neutron Knockout

21st International Conference on Few-Body Problems in Physics, Chicago, IL, USA, May 18-22, 2015.The spectroscopic structure of ¹⁹C, a prominent one-neutron halo nucleus, has been studied with a ²⁰C secondary beam at 290 MeV/nucleon and a carbon target. Neutron-unbound states populated by the one-neutron knockout reaction were investigated by means of the invariant mass method. The preliminary relative energy spectrum and parallel momentum distribution of the knockout residue, ¹⁹C∗, were reconstructed from the measured four momenta of the¹⁸C fragment, neutron, and beam. Three resonances were observed in the spectrum, which correspond to the states at Ex = 0.62(9), 1.42(10), and 2.89(10) MeV. The parallel momentum distributions for the 0.62-MeV and 2.89-MeV states suggest spin-parity assignments of 5/2⁺ and 1/2⁻, respectively. The 1.42-MeV state is in line with the reported 5/22⁺ state

Spectroscopy of the Unbound Nucleus Na-18

The unbound nucleus Na-18, the intermediate nucleus in the two-proton radioactivity of Mg-19 is studied through the resonant elastic scattering Ne-17(p,Ne-17)p. The spectroscopic information obtained in this experiment is discussed and put in perspective with previous measurements and the structure of the mirror nucleus N-18.2nd Workshop on State of the Art in Nuclear Cluster Physics, May 25-28, 2010, Univ Libre Brussels, Brussels, Belgiu

Spectroscopy of 17C via one-neutron knockout reaction

A spectroscopic study of 17C was performed via the one-neutron knockout reaction of 18C on a carbon target at RIKEN-RIBF. Three unbound states at excitation energies of 2.66(2), 3.16(5), and 3.97(3) MeV (preliminary) were observed. The energies are compared with shell-model calculations and existing measurements to deduce their spin-parities. From the comparison, the states at 2.66(2) and 3.97(3) MeV are suggested to be 1/2− and 3/2−, respectively. From its decay property, the state at 3.16(5) MeV is indicated to be 9/2+

Spectroscopy of C-17 Above the Neutron Separation Energy

Spectroscopy of an unbound nucleus C-17 was performed using the SAMURAI spectrometer at RIBF of RIKEN. Six resonances were observed for the C-16+n system with relative energies of 0.52, 0.77, 1.36, 1.91, 2.22 and 3.20 MeV. The excitation energies (E-x) of the observed resonances were deduced, by taking into account the states of the C-16 fragments identified by coincident gamma rays, as E-x =(3.02), 1.51, (3.86), 2.65, (4.72) and 3.94MeV. The orbital angular momenta of the two observed states in C-17 at E-x =2.65 and 3.94 MeV were determined as 1 by comparing parallel momentum distributions with theoretical predictions.11Nsciescopu

Study of 19C by One-Neutron Knockout

The spectroscopic structure of 19C, a prominent one-neutron halo nucleus, has been studied with a 20C secondary beam at 290 MeV/nucleon and a carbon target. Neutron-unbound states populated by the one-neutron knockout reaction were investigated by means of the invariant mass method. The preliminary relative energy spectrum and parallel momentum distribution of the knockout residue, 19C*, were reconstructed from the measured four momenta of the 18C fragment, neutron, and beam. Three resonances were observed in the spectrum, which correspond to the states at Ex = 0.62(9), 1.42(10), and 2.89(10) MeV. The parallel momentum distributions for the 0.62-MeV and 2.89-MeV states suggest spin-parity assignments of 5/2+ and 1/2−, respectively. The 1.42-MeV state is in line with the reported 5/22+ state