Puzzling $B(E2;0^+\rightarrow 2^+)$ strength in the proton dripline nucleus $^{36}$Ca

Fuente: arXiv
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Main Authors: Xu, Z. C., Wang, S. M., Beck, T., Gade, A., Nazarewicz, W.
Format: Preprint
Published: 2025
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author Xu, Z. C.
Wang, S. M.
Beck, T.
Gade, A.
Nazarewicz, W.
author_facet Xu, Z. C.
Wang, S. M.
Beck, T.
Gade, A.
Nazarewicz, W.
contents Recent measurements of the $E2$ transition rate from the ground state to the first 2$^+$ excited state of the proton dripline nucleus $^{36}$Ca show an unusual pattern when compared to its isotopic neighbor $^{38}$Ca: despite having a higher $E_x(2_1^+)$ excitation energy, the $B(E2; 0^+_1\rightarrow 2^+_1)$ rate in $^{36}$Ca is larger. The question that naturally arises is to what extent this observation can be attributed to the unbound character of the $2^+_1$ state. To understand the influence of the continuum space on the low-energy properties of $^{36}$Ca, we carried out Gamow shell model calculations that can account for the continuum coupling effects associated with the occupation of unbound $fp$ shells. We found that in the threshold $2^+$ state, $^{36}$Ca is spatially diffused, which impacts the observed $B(E2)$ trend.
format Preprint
id arxiv_https___arxiv_org_abs_2502_14106
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Puzzling $B(E2;0^+\rightarrow 2^+)$ strength in the proton dripline nucleus $^{36}$Ca
Xu, Z. C.
Wang, S. M.
Beck, T.
Gade, A.
Nazarewicz, W.
Nuclear Theory
Nuclear Experiment
Recent measurements of the $E2$ transition rate from the ground state to the first 2$^+$ excited state of the proton dripline nucleus $^{36}$Ca show an unusual pattern when compared to its isotopic neighbor $^{38}$Ca: despite having a higher $E_x(2_1^+)$ excitation energy, the $B(E2; 0^+_1\rightarrow 2^+_1)$ rate in $^{36}$Ca is larger. The question that naturally arises is to what extent this observation can be attributed to the unbound character of the $2^+_1$ state. To understand the influence of the continuum space on the low-energy properties of $^{36}$Ca, we carried out Gamow shell model calculations that can account for the continuum coupling effects associated with the occupation of unbound $fp$ shells. We found that in the threshold $2^+$ state, $^{36}$Ca is spatially diffused, which impacts the observed $B(E2)$ trend.
title Puzzling $B(E2;0^+\rightarrow 2^+)$ strength in the proton dripline nucleus $^{36}$Ca
topic Nuclear Theory
Nuclear Experiment
url https://arxiv.org/abs/2502.14106