arXiv subjects

J. N. Orce

Publications and source records attributed to J. N. Orce.

21 records · Page 2Linked to original sources

arXiv2007

Shape Coexistence and Mixing in 152Sm

Experimental studies of 152Sm using multiple-step Coulomb excitation and inelastic neutron scattering provide key data that clarify the low-energy collective structure of this nucleus. No candidates for two-phonon beta-vibrational states are found. Experimental level energies of the ground-state and first excited (0+ state) rotational bands, electric monopole transition rates, reduced quadrupole transition rates, and the isomer shift of the first excited 2+ state are all described within ~10% precision using two-band mixing calculations. The basic collective structure of 152Sm is described using strong mixing of near-degenerate coexisting quasi-rotational bands with different deformations.

nucl-ex↗

arXiv2006

Identification of mixed-symmetry states in an odd-mass nearly-spherical nucleus

The low-spin structure of 93Nb has been studied using the (n,n' gamma) reaction at neutron energies ranging from 1.5 to 3.0 MeV and the 94Zr(p,2n gamma)93Nb reaction at bombarding energies from 11.5 to 19 MeV. States at 1779.7 and 1840.6 keV, respectively, are proposed as mixed-symmetry states associated with the coupling of a proton hole in the p_1/2 orbit to the 2+_1,ms state in 94Mo. These assignments are derived from the observed M1 and E2 transition strengths to the symmetric one-phonon states, energy systematics, spins and parities, and comparison with shell model calculations.

nucl-ex↗

arXiv2006

Charge-independent trend of isoscalar matrix elements along the $N \sim Z$ line

Shell model calculations have been carried out using the m-scheme numerical code {\small ANTOINE} in order to elucidate the particular trend of the isoscalar matrix elements, $M_0$, for $A=4n+2$ isobaric triplets ranging from A=18 to A=42. The 2${_1^+}_{(T=1)}$ $\to$ 0${_1^+}_{(T=1)}$ transition energies, reduced transition probabilities and isoscalar matrix elements are predicted to a high degree of accuracy. The general agreement of $M_0$ between those from mirror pairs and those from $T_Z=0$ nuclides support our shell model calculations. The predicted results tie together recent experimental data, and the trend of $M_0$ strength along the $sd$ and beginning of the $fp$ shells is interpreted in terms of the dynamic shell structure. Certain discrepancies arise at A=18 and A=38 isobaric triplets, which might be explained in terms of core polarization effects and the low occupancy of the orbits at the extremes of the $sd$ shell.

nucl-th↗