Saved in:
| Main Authors: | , , , , , , , , , , , |
|---|---|
| Format: | Preprint |
| Published: |
2025
|
| Subjects: | |
| Online Access: | https://arxiv.org/abs/2508.09643 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1866915443970670592 |
|---|---|
| author | Reece, M. Coombes, B. J. Mitchell, A. J. Stuchbery, A. E. Lane, G. J. Gargano, A. Bashu, V. U. Bignell, L. J. Gautam, C. McKie, L. J. Spinks, N. J. Woodside, J. A. |
| author_facet | Reece, M. Coombes, B. J. Mitchell, A. J. Stuchbery, A. E. Lane, G. J. Gargano, A. Bashu, V. U. Bignell, L. J. Gautam, C. McKie, L. J. Spinks, N. J. Woodside, J. A. |
| contents | The low-lying energy spectra of even-even tellurium isotopes near midshell have long been interpreted as `textbook' examples of vibrational collective motion. However, in many cases electric-quadrupole observables, which are a particularly sensitive probe of collectivity, remain undetermined. Coulomb-excitation measurements were performed to measure transition strengths connecting the ground and low-excitation states in $^{124}$Te. This isotope lies at a transitional point between collective structure near the neutron midshell and seniority structures near the $N=82$ shell. A transition strength, $B(E2; 6_1^+ \to 4_1^+)$, of 27(9)~W.u. was measured for the $6^+_1\rightarrow4^+_1$ transition for the first time in this nucleus; this value is significantly below that expected for a spherical vibrator, as well as other collective models. We examine the transition strengths in $^{124}$Te and its neighbors by comparison with large-basis shell-model calculations and by comparison with General Collective Model (GCM) fits. A GCM description of $^{120}$Te agrees with experimental $E2$ transition strengths, but no comparable description of $^{124}$Te is possible with the GCM. In contrast, there is remarkably good agreement between the $B(E2; 6_1^+ \to 4_1^+)$ values and shell-model calculations for $^{124-134}$Te. It appears that, despite approaching midshell, $^{124}$Te retains a seniority structure for the $6^+_1$ level, i.e. a significant $π0g_{7/2}^2$ contribution. This persistence of the shell structure at the $6^+_1$ state is in contrast to the $B(E2)$ values of the lower-excitation $2^+_1$ and $4^+_1$ states in $^{124}$Te, and neighboring $^{120}$Te and $^{122}$Te, for which the collectivity becomes enhanced as more neutrons are removed from $N=82$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_09643 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Coulomb excitation of $^{124}$Te: Emerging collectivity and persisting seniority structure in the $6_1^+$ level Reece, M. Coombes, B. J. Mitchell, A. J. Stuchbery, A. E. Lane, G. J. Gargano, A. Bashu, V. U. Bignell, L. J. Gautam, C. McKie, L. J. Spinks, N. J. Woodside, J. A. Nuclear Experiment Nuclear Theory The low-lying energy spectra of even-even tellurium isotopes near midshell have long been interpreted as `textbook' examples of vibrational collective motion. However, in many cases electric-quadrupole observables, which are a particularly sensitive probe of collectivity, remain undetermined. Coulomb-excitation measurements were performed to measure transition strengths connecting the ground and low-excitation states in $^{124}$Te. This isotope lies at a transitional point between collective structure near the neutron midshell and seniority structures near the $N=82$ shell. A transition strength, $B(E2; 6_1^+ \to 4_1^+)$, of 27(9)~W.u. was measured for the $6^+_1\rightarrow4^+_1$ transition for the first time in this nucleus; this value is significantly below that expected for a spherical vibrator, as well as other collective models. We examine the transition strengths in $^{124}$Te and its neighbors by comparison with large-basis shell-model calculations and by comparison with General Collective Model (GCM) fits. A GCM description of $^{120}$Te agrees with experimental $E2$ transition strengths, but no comparable description of $^{124}$Te is possible with the GCM. In contrast, there is remarkably good agreement between the $B(E2; 6_1^+ \to 4_1^+)$ values and shell-model calculations for $^{124-134}$Te. It appears that, despite approaching midshell, $^{124}$Te retains a seniority structure for the $6^+_1$ level, i.e. a significant $π0g_{7/2}^2$ contribution. This persistence of the shell structure at the $6^+_1$ state is in contrast to the $B(E2)$ values of the lower-excitation $2^+_1$ and $4^+_1$ states in $^{124}$Te, and neighboring $^{120}$Te and $^{122}$Te, for which the collectivity becomes enhanced as more neutrons are removed from $N=82$. |
| title | Coulomb excitation of $^{124}$Te: Emerging collectivity and persisting seniority structure in the $6_1^+$ level |
| topic | Nuclear Experiment Nuclear Theory |
| url | https://arxiv.org/abs/2508.09643 |