Physics Letters B (Feb 2018)
Reorientation-effect measurement of the first 2+ state in 12C: Confirmation of oblate deformation
- M. Kumar Raju,
- J.N. Orce,
- P. Navrátil,
- G.C. Ball,
- T.E. Drake,
- S. Triambak,
- G. Hackman,
- C.J. Pearson,
- K.J. Abrahams,
- E.H. Akakpo,
- H. Al Falou,
- R. Churchman,
- D.S. Cross,
- M.K. Djongolov,
- N. Erasmus,
- P. Finlay,
- A.B. Garnsworthy,
- P.E. Garrett,
- D.G. Jenkins,
- R. Kshetri,
- K.G. Leach,
- S. Masango,
- D.L. Mavela,
- C.V. Mehl,
- M.J. Mokgolobotho,
- C. Ngwetsheni,
- G.G. O'Neill,
- E.T. Rand,
- S.K.L. Sjue,
- C.S. Sumithrarachchi,
- C.E. Svensson,
- E.R. Tardiff,
- S.J. Williams,
- J. Wong
Affiliations
- M. Kumar Raju
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa; iThemba LABS, National Research Foundation, PO Box 722, 7129 Somerset West, South Africa
- J.N. Orce
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa; Corresponding author.
- P. Navrátil
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- G.C. Ball
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- T.E. Drake
- Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada
- S. Triambak
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa; iThemba LABS, National Research Foundation, PO Box 722, 7129 Somerset West, South Africa
- G. Hackman
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- C.J. Pearson
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- K.J. Abrahams
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa
- E.H. Akakpo
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa
- H. Al Falou
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- R. Churchman
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- D.S. Cross
- Department of Chemistry, Simon Fraser University, British Columbia V5A 1S6, Canada
- M.K. Djongolov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- N. Erasmus
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa
- P. Finlay
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- A.B. Garnsworthy
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- P.E. Garrett
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- D.G. Jenkins
- Department of Physics, University of York, York YO10 5DD, United Kingdom
- R. Kshetri
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada; Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
- K.G. Leach
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- S. Masango
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa
- D.L. Mavela
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa
- C.V. Mehl
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa
- M.J. Mokgolobotho
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa
- C. Ngwetsheni
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa
- G.G. O'Neill
- Department of Physics & Astronomy, University of the Western Cape, Bellville-7535, South Africa
- E.T. Rand
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- S.K.L. Sjue
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- C.S. Sumithrarachchi
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- C.E. Svensson
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
- E.R. Tardiff
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- S.J. Williams
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- J. Wong
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Journal volume & issue
-
Vol. 777
pp. 250 – 254
Abstract
A Coulomb-excitation reorientation-effect measurement using the TIGRESS γ−ray spectrometer at the TRIUMF/ISAC II facility has permitted the determination of the 〈21+‖E2ˆ‖21+〉 diagonal matrix element in 12C from particle−γ coincidence data and state-of-the-art no-core shell model calculations of the nuclear polarizability. The nuclear polarizability for the ground and first-excited (21+) states in 12C have been calculated using chiral NN N4LO500 and NN+3NF350 interactions, which show convergence and agreement with photo-absorption cross-section data. Predictions show a change in the nuclear polarizability with a substantial increase between the ground state and first excited 21+ state at 4.439 MeV. The polarizability of the 21+ state is introduced into the current and previous Coulomb-excitation reorientation-effect analyses of 12C. Spectroscopic quadrupole moments of QS(21+)=+0.053(44) eb and QS(21+)=+0.08(3) eb are determined, respectively, yielding a weighted average of QS(21+)=+0.071(25) eb, in agreement with recent ab initio calculations. The present measurement confirms that the 21+ state of 12C is oblate and emphasizes the important role played by the nuclear polarizability in Coulomb-excitation studies of light nuclei. Keywords: Reorientation effect, Spectroscopic quadrupole moment, Ab initio calculations, Nuclear polarizability
