Nuclear Theory·nucl-th

Monday·May 11, 2020

8 papers—5 primary·3 cross-listed

06
Coulomb excitation of the $∣ T_{z} ∣ = \frac{1}{2}$ , $A = 23$ mirror pair
J. Henderson · G. Hackman · P. Ruotsalainen · J. D. Holt · S. R. Stroberg · C. Andreoiu · G. C. Ball · N. Bernier · M. Bowry · R. Caballero-Folch · S. Cruz · A. Diaz Varela and 14 other authors
Background: Electric-quadrupole ( $E 2$ ) strengths relate to the underlying quadrupole deformation of a nucleus and present a challenge for many nuclear theories. Mirror nuclei in the vicinity of the line of $N = Z$ represent a convenient laboratory for testing deficiencies in such models, making use of the isospin-symmetry of the systems. Purpose: Uncertainties associated with literature $E 2$ strengths in \textsuperscript{23}Mg are some of the largest in $T_{z} = \frac{1}{2}$ nuclei in the $s d$ -shell. The purpose of the present work is to improve the precision with which these values are known, to enable better comparison with theoretical models. Methods: Coulomb-excitation measurements of $^{23}$ Mg and $^{23}$ Na were performed at the TRIUMF-ISAC facility using the TIGRESS spectrometer. They were used to determine the $E 2$ matrix elements of mixed $E 2$ / $M 1$ transitions. Results: Reduced $E 2$ transition strengths, $B (E 2)$ , were extracted for \textsuperscript{23}Mg and \textsuperscript{23}Na. Their precision was improved by factors of approximately six for both isotopes, while agreeing within uncertainties with previous measurements. Conclusions: A comparison was made with both shell-model and {\it ab initio} valence-space in-medium similarity renormalization group calculations. Valence-space in-medium similarity-renormalization-group calculations were found to underpredict the absolute $E 2$ strength - in agreement with previous studies.
↳ nucl-exnucl-thPRC(2022)·19 citations
07
Precision measurement of the $E 2$ transition strength to the 2 $_{1}^{+}$ state of $^{12}$ C
A. D'Alessio · T. Mongelli · M. Arnold · S. Bassauer · J. Birkhan · M. Hilcker · T. Hüther · J. Isaak · L. Jürgensen · T. Klaus · P. von Neumann-Cosel · N. Pietralla and 7 other authors
The form factor of the electromagnetic excitation of $^{12}$ C to its 2 $_{1}^{+}$ state was measured at extremely low momentum transfers in an electron scattering experiment at the S-DALINAC. A combined analysis with the world form factor data results in a reduced transition strength $B (E 2; 2_{1}^{+} \to 0_{1}^{+}) = 7.63 (19)$ e $^{2}$ fm $^{4}$ with an accuracy improved to 2.5\%. In-Medium-No Core Shell Model results with interactions derived from chiral effective field theory are capable to reproduce the result. A quadrupole moment $Q (2_{1}^{+}) = 5.97 (30)$ efm $^{2}$ can be extracted from the strict correlation with the $B ((E 2)$ strength emerging in the calculations.
↳ nucl-exnucl-thPRC(2020)·16 citations
08
Evolution of the dipole polarizability in the stable tin isotope chain
S. Bassauer (1) · P. von Neumann-Cosel (1) · P.-G. Reinhard (2) · A. Tamii (3) · S. Adachi (3) · C. A. Bertulani (4) · P. Y. Chan (3) · G. Colò (5) · A. D'Alessio (1) · H. Fujioka (6) · H. Fujita (3) · Y. Fujita (3) and 27 other authors
The dipole polarizability of stable even-mass tin isotopes 112,114,116,118,120,124 was extracted from inelastic proton scattering experiments at 295 MeV under very forward angles performed at RCNP. Predictions from energy density functionals cannot account for the present data and the polarizability of 208Pb simultaneously. The evolution of the polarizabilities in neighboring isotopes indicates a kink at 120Sn while all model results show a nearly linear increase with mass number after inclusion of pairing corrections.
↳ nucl-exnucl-thPLB(2020)·28 citations

Affiliations

first authorsco-authorsvia INSPIRE

Coulomb excitation of the ∣Tz​∣=21​, A=23 mirror pair

Precision measurement of the E2 transition strength to the 21+​ state of 12C

Evolution of the dipole polarizability in the stable tin isotope chain

Affiliations

Coulomb excitation of the $∣ T_{z} ∣ = \frac{1}{2}$ , $A = 23$ mirror pair

Precision measurement of the $E 2$ transition strength to the 2 $_{1}^{+}$ state of $^{12}$ C