dorsal/arxiv
View SchemaAre There Low-Lying Intruder States in ^8Be?
| Authors | M. S. Fayache, L. Zamick, Y. Y. Sharon |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9706073 |
| URL | https://arxiv.org/abs/nucl-th/9706073 |
Abstract
We allow up to $4 \hbar\omega$ excitations in $^8Be$ relative to the basic configuration $(0s)^4(0p)^4$ in order to see if there are low-lying intruder states in $^8Be$. We use three interactions $-\chi Q \cdot Q, -\chi Q \cdot Q$ + spin-orbit, and a realistic (x,y) interaction, where for $x=1,y=1$ one gets values for the spin-orbit and tensor interactions which correspond closely to those of a non-relativistic $G$ matrix such as Bonn A. For the three interactions considered, if we allow up to $2 \hbar \omega$ excitations we get the energy of the lowest $J=0^+$ intruder state to be at 32.1 MeV, 30.1 MeV and 33.8 MeV, respectively. If we allow up to $4 \hbar\omega$ excitations the corresponding values are 26.5 MeV, 26.5 MeV and 28.7 MeV. We thus support the statement made by E. Warburton in his 1986 $R$ matrix analysis of the $\beta^{\mp}$-delayed alpha spectra from the decay of $^8Li$ and $^8B$ that ``satisfactory fits are obtained without introducing intruder states below 26-MeV excitations'' (Phys. Rev. C 33, 303(1986)). In $^{10}Be$ however, with the first two ``$Q \cdot Q$'' interactions, we get (with up to $2 \hbar \omega$ excitations) low-lying intruder states at 9.7 MeV and 11.9 MeV respectively. Thus the presence of low-lying intruder states in $^{10}Be$ (the $0^+_2$ state at 6.179 MeV may or may not be an intruder) does not imply that there are low-lying intruder states in $^8Be$.
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"abstract": "We allow up to $4 \\hbar\\omega$ excitations in $^8Be$ relative to the basic\nconfiguration $(0s)^4(0p)^4$ in order to see if there are low-lying intruder\nstates in $^8Be$. We use three interactions $-\\chi Q \\cdot Q, -\\chi Q \\cdot Q$\n+ spin-orbit, and a realistic (x,y) interaction, where for $x=1,y=1$ one gets\nvalues for the spin-orbit and tensor interactions which correspond closely to\nthose of a non-relativistic $G$ matrix such as Bonn A. For the three\ninteractions considered, if we allow up to $2 \\hbar \\omega$ excitations we get\nthe energy of the lowest $J=0^+$ intruder state to be at 32.1 MeV, 30.1 MeV and\n33.8 MeV, respectively. If we allow up to $4 \\hbar\\omega$ excitations the\ncorresponding values are 26.5 MeV, 26.5 MeV and 28.7 MeV. We thus support the\nstatement made by E. Warburton in his 1986 $R$ matrix analysis of the\n$\\beta^{\\mp}$-delayed alpha spectra from the decay of $^8Li$ and $^8B$ that\n``satisfactory fits are obtained without introducing intruder states below\n26-MeV excitations\u0027\u0027 (Phys. Rev. C 33, 303(1986)). In $^{10}Be$ however, with\nthe first two ``$Q \\cdot Q$\u0027\u0027 interactions, we get (with up to $2 \\hbar \\omega$\nexcitations) low-lying intruder states at 9.7 MeV and 11.9 MeV respectively.\nThus the presence of low-lying intruder states in $^{10}Be$ (the $0^+_2$ state\nat 6.179 MeV may or may not be an intruder) does not imply that there are\nlow-lying intruder states in $^8Be$.",
"arxiv_id": "nucl-th/9706073",
"authors": [
"M. S. Fayache",
"L. Zamick",
"Y. Y. Sharon"
],
"categories": [
"nucl-th"
],
"title": "Are There Low-Lying Intruder States in ^8Be?",
"url": "https://arxiv.org/abs/nucl-th/9706073"
},
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